Faculty Profiles - NAKAMURA Yoshimasa

Papers - NAKAMURA Yoshimasa

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Cycloartenyl Ferulate from Rice as a Biologically Active Antioxidant Invited Reviewed

NAKAMURA Yoshimasa

Oleoscience 25 ( 5 ) 199 - 204 2025

Authorship：Lead author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Oil Chemists' Society

Rice serves as an excellent source of antioxidants such as vitamin Es, ferulic acid, and γ-oryzanols as well as starch. Since these antioxidants are abundant in the rice bran layer and germ parts, it has been considered that brown rice is more physiologically active than white rice. However, it remains unclear how much the chemical or biological antioxidant activity of brown rice differs from that of white rice in terms of quality and quantity. Our research group has shown that, at the level of extracts, white rice exhibits chemical or biological antioxidant activity comparable to that of brown rice. In addition, the contribution of cycloartenyl ferulate (CAF), a major molecular species of γ-oryzanols, to the biological antioxidant activity of rice was found to be much greater than that of vitamin Es. Based on these results, this review highlights the potential of CAF for health functions based on their antioxidant properties.

DOI： 10.5650/oleoscience.25.199

Quercetin Attenuates Acetaldehyde-Induced Cytotoxicity via the Heme Oxygenase-1-Dependent Antioxidant Mechanism in Hepatocytes Invited Reviewed International journal

Kexin Li, Minori Kidawara, Qiguang Chen, Shintaro Munemasa, Yoshiyuki Murata, Toshiyuki Nakamura, Yoshimasa Nakamura

International Journal of Molecular Sciences 25 ( 16 ) 2024.8

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

It is still unclear whether or how quercetin influences the toxic events induced by acetaldehyde in hepatocytes, though quercetin has been reported to mitigate alcohol-induced mouse liver injury. In this study, we evaluated the modulating effect of quercetin on the cytotoxicity induced by acetaldehyde in mouse hepatoma Hepa1c1c7 cells, the frequently used cellular hepatocyte model. The pretreatment with quercetin significantly inhibited the cytotoxicity induced by acetaldehyde. The treatment with quercetin itself had an ability to enhance the total ALDH activity, as well as the ALDH1A1 and ALDH3A1 gene expressions. The acetaldehyde treatment significantly enhanced the intracellular reactive oxygen species (ROS) level, whereas the quercetin pretreatment dose-dependently inhibited it. Accordingly, the treatment with quercetin itself significantly up-regulated the representative intracellular antioxidant-related gene expressions, including heme oxygenase-1 (HO-1), glutamate-cysteine ligase, catalytic subunit (GCLC), and cystine/glutamate exchanger (xCT), that coincided with the enhancement of the total intracellular glutathione (GSH) level. Tin protoporphyrin IX (SNPP), a typical HO-1 inhibitor, restored the quercetin-induced reduction in the intracellular ROS level, whereas buthionine sulphoximine, a representative GSH biosynthesis inhibitor, did not. SNPP also cancelled the quercetin-induced cytoprotection against acetaldehyde. These results suggest that the low-molecular-weight antioxidants produced by the HO-1 enzymatic reaction are mainly attributable to quercetin-induced cytoprotection.

DOI： 10.3390/ijms25169038

Evaluation of quercetin as a potential cytoprotector against acetaldehyde using the cultured hepatocyte model with aldehyde dehydrogenase isozyme deficiency. Reviewed International journal

Yuhang Xu, Takeshi Sawamoto, Ruitong Sun, Aki Ishikura, Shintaro Munemasa, Yoshiyuki Murata, Ayano Satoh, Akiko Matsumoto, Toshiyuki Nakamura, Yoshimasa Nakamura

Bioscience, biotechnology, and biochemistry 2024.7

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

Protective effect of quercetin against acetaldehyde was evaluated using the cultured hepatocyte models with aldehyde dehydrogenase (ALDH) isozyme deficiency (aldh2-kd and aldh1a1-kd). The quercetin-induced cytoprotection against acetaldehyde in the ALDH1A1-deficient mutant (aldh1a1-kd) was weaker than that in wild type. Furthermore, quercetin did not enhance the ALDH activity in aldh1a1-kd cells, suggesting that ALDH1A1 is involved in the quercetin-induced cytoprotection.

DOI： 10.1093/bbb/zbae100

Cycloartenyl Ferulate Is the Predominant Compound in Brown Rice Conferring Cytoprotective Potential against Oxidative Stress-Induced Cytotoxicity Invited Reviewed

Hongyan Wu, Toshiyuki Nakamura, Yingnan Guo, Riho Matsumoto, Shintaro Munemasa, Yoshiyuki Murata, Yoshimasa Nakamura

International Journal of Molecular Sciences 24 ( 1 ) 822 - 822 2023.1

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG

Since brown rice extract is a rich source of biologically active compounds, the present study is aimed to quantify the major compounds in brown rice and to compare their cytoprotective potential against oxidative stress. The content of the main hydrophobic compounds in brown rice followed the order of cycloartenyl ferulate (CAF) (89.00 ± 8.07 nmol/g) >> α-tocopherol (αT) (19.73 ± 2.28 nmol/g) > γ-tocotrienol (γT3) (18.24 ± 1.41 nmol/g) > α-tocotrienol (αT3) (16.02 ± 1.29 nmol/g) > γ-tocopherol (γT) (3.81 ± 0.40 nmol/g). However, the percent contribution of CAF to the radical scavenging activity of one gram of whole brown rice was similar to those of αT, αT3, and γT3 because of its weaker antioxidant activity. The CAF pretreatment displayed a significant cytoprotective effect on the hydrogen peroxide-induced cytotoxicity from 10 µM, which is lower than the minimal concentrations of αT and γT required for a significant protection. CAF also enhanced the nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation coincided with the enhancement of the heme oxygenase-1 (HO-1) mRNA level. An HO-1 inhibitor, tin protoporphyrin IX (SnPP), significantly impaired the cytoprotection of CAF. The cytoprotective potential of CAF is attributable to its cycloartenyl moiety besides the ferulyl moiety. These results suggested that CAF is the predominant cytoprotector in brown rice against hydrogen peroxide-induced cytotoxicity.

DOI： 10.3390/ijms24010822

The microbiota catabolites of quercetin glycosides concertedly enhance the resistance against acetaldehyde-induced oxidative stress. Reviewed International journal

Kexin Li, Hongyan Wu, Minori Kidawara, Yun Lin, Ayano Satoh, Gongliang Zhang, Shintaro Munemasa, Yoshiyuki Murata, Toshiyuki Nakamura, Yoshimasa Nakamura

Free radical research 56 ( 9-10 ) 1 - 14 2022.12

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

3,4-Dihydroxyphenylacetic acid (DOPAC) and 3-hydroxyphenylacetic acid (OPAC) are the predominant catabolites of quercetin glycosides, such as quercetin 4'-O-β-glucoside from the onion, produced by intestinal microbiota. Although each catabolite has been reported to protect the cells from acetaldehyde-induced cytotoxicity, the effect of their combination remains to be clarified. The purpose of this study was to determine whether the combination of DOPAC and OPAC enhances the resistance against the acetaldehyde-induced oxidative stress in the cultured hepatocytes. The pretreatment of the combination of DOPAC (5 μM) and OPAC (5 μM) showed the significant protection against the acetaldehyde- and hydrogen peroxide-induced cytotoxicity, even though each compound at the same concentration did not. This combination also significantly inhibited the intracellular dichlorofluorescin diacetate-detectable reactive oxygen species (ROS) level, whereas the solo treatment did slightly, suggesting that reducing mechanisms of ROS or compounds that enhance ROS production are involved in the cytoprotective effect. The combinatory treatment significantly enhanced the gene expression of not only the aldehyde dehydrogenases (ALDHs), but also glutamate-cysteine ligase, catalytic subunit, the first rate-limiting enzyme of glutathione (GSH) synthesis. Accordingly, both the intracellular GSH level and the total ALDH activity were enhanced by DOPAC plus OPAC. Involvement of GSH in the cytoprotection as well as ALDH up-regulation by the combination were confirmed by the experiments using a GSH biosynthesis inhibitor, buthionine sulfoximine. Taken together, the present results suggested that the quercetin microbiota catabolites concertedly protect the cells from acetaldehyde through a pre-enhanced resistance against oxidative stress by the GSH-dependent up-regulation of ALDHs.

DOI： 10.1080/10715762.2022.2159820

Benzyl isothiocyanate and its metabolites inhibit cell proliferation through protein modification in mouse preosteoclast RAW264.7 cells. Reviewed International journal

Toshiyuki Nakamura, Chiharu Tsutsui, Yu Okuda, Naomi Abe-Kanoh, Saori Okazawa, Shintaro Munemasa, Yoshiyuki Murata, Yoji Kato, Yoshimasa Nakamura

Journal of biochemical and molecular toxicology e23184 2022.8

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

Benzyl isothiocyanate (BITC), derived from cruciferous vegetables, is an organosulfur compound exerting antiproliferative effects in several human cancer cells. In this study, we assessed BITC as a potential osteoclastogenesis inhibitor and investigated its underlying mechanism. BITC at 5 μM significantly decreased the viability of the osteoclast-like differentiating RAW264.7 cells, coinciding with the downregulation of the primary biomarkers for osteoclast differentiation, such as the tartrate-resistant acid phosphatase activity and nuclear factor of activated T-cells gene expression. Not only BITC but also its metabolites, inhibited cell proliferation in the normal RAW264.7 cells, suggesting that BITC shows an anti-osteoclastogenesis effect in vivo after its ingestion and metabolism, possibly through an antiproliferative action. Both BITC and its metabolites also enhanced the DNA fragmentation and the caspase-3 activity, whereas their higher concentrations tended to suppress these effects. BITC was intracellularly accumulated when the cells were treated with its metabolites via their degradation into the free form. A quantitative experiment using the proteolysis/high performance liquid chromatography technique showed that the amount of BITC-lysine thiourea in the cells was also increased in a time-dependent manner, suggesting that lysine modification of the cellular proteins actually took place in the cells treated by BITC. Among the cellular proteins, the cleaved caspase-3 was identified as a potential target for lysine modification by BITC. Taken together, BITC dissociated from its metabolites as well as its free form might modulate osteoclastogenesis, possibly through inhibition of cell proliferation by protein modification.

DOI： 10.1002/jbt.23184

A Major Intestinal Catabolite of Quercetin Glycosides, 3-Hydroxyphenylacetic Acid, Protects the Hepatocytes from the Acetaldehyde-Induced Cytotoxicity through the Enhancement of the Total Aldehyde Dehydrogenase Activity Invited Reviewed International journal

Yujia Liu, Takumi Myojin, Kexin Li, Ayuki Kurita, Masayuki Seto, Ayano Motoyama, Xiaoyang Liu, Ayano SATOH, Shintaro Munemasa, Yoshiyuki Murata, Toshiyuki Nakamura, Yoshimasa Nakamura

International Journal of Molecular Sciences 23 ( 3 ) 2022.2

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

Aldehyde dehydrogenases (ALDHs) are the major enzyme superfamily for the aldehyde metabolism. Since the ALDH polymorphism leads to the accumulation of acetaldehyde, we considered that the enhancement of the liver ALDH activity by certain food ingredients could help prevent alcohol-induced chronic diseases. Here, we evaluated the modulating effects of 3-hydroxyphenylacetic acid (OPAC), the major metabolite of quercetin glycosides, on the ALDH activity and acetaldehyde-induced cytotoxicity in the cultured cell models. OPAC significantly enhanced the total ALDH activity not only in mouse hepatoma Hepa1c1c7 cells, but also in human hepatoma HepG2 cells. OPAC significantly increased not only the nuclear level of aryl hydrocarbon receptor (AhR), but also the AhR-dependent reporter gene expression, though not the nuclear factor erythroid-2-related factor 2 (Nrf2)-dependent one. The pretreatment of OPAC at the concentration required for the ALDH upregulation completely inhibited the acetaldehyde-induced cytotoxicity. Silencing AhR impaired the resistant effect of OPAC against acetaldehyde. These results strongly suggested that OPAC protects the cells from the acetaldehyde-induced cytotoxicity, mainly through the AhR-dependent and Nrf2-independent enhancement of the total ALDH activity. Our findings suggest that OPAC has a protective potential in hepatocyte models and could offer a new preventive possibility of quercetin glycosides for targeting alcohol-induced chronic diseases.

DOI： 10.3390/ijms23031762

Characterization of benzyl isothiocyanate extracted from mashed green papaya by distillation. Reviewed International journal

Nakamura T, Murata Y, Nakamura Y

Food chemistry 299 125118 - 125118 2019.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

The aim of this study was to extract benzyl isothiocyanate (BITC) from green papaya by distillation apparatus without using organic solvents, and to improve the stability of BITC in aqueous solution. The distillation of mashed green papaya successfully yielded BITC as a water solution with more than 80% purity with good reproducibility. The amount of BITC in the distilled water gradually decreased during its storage at 4 °C, whereas it was not significantly changed at -20 °C for a few months. Moreover, the addition of l-cysteine ameliorated the BITC decomposition by the 4 °C-storage, but not affected by N-acetyl-cysteine and glutathione. These results suggested that the combination of BITC extraction by distillation and cysteine supplementation as well as frozen storage might be a useful method for the preparation and storage of the safer grade of BITC-containing extract.

DOI： 10.1016/j.foodchem.2019.125118

Yeast screening system reveals the inhibitory mechanism of cancer cell proliferation by benzyl isothiocyanate through down-regulation of Mis12. Reviewed International journal

Naomi Abe-Kanoh, Narumi Kunisue, Takumi Myojin, Ayako Chino, Shintaro Munemasa, Yoshiyuki Murata, Ayano Satoh, Hisao Moriya, Yoshimasa Nakamura

Scientific reports 9 ( 1 ) 8866 - 8866 2019.6

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

Benzyl isothiocyanate (BITC) is a naturally-occurring isothiocyanate derived from cruciferous vegetables. BITC has been reported to inhibit the proliferation of various cancer cells, which is believed to be important for the inhibition of tumorigenesis. However, the detailed mechanisms of action remain unclear. In this study, we employed a budding yeast Saccharomyces cerevisiae as a model organism for screening. Twelve genes including MTW1 were identified as the overexpression suppressors for the antiproliferative effect of BITC using the genome-wide multi-copy plasmid collection for S. cerevisiae. Overexpression of the kinetochore protein Mtw1 counteracts the antiproliferative effect of BITC in yeast. The inhibitory effect of BITC on the proliferation of human colon cancer HCT-116 cells was consistently suppressed by the overexpression of Mis12, a human orthologue of Mtw1, and enhanced by the knockdown of Mis12. We also found that BITC increased the phosphorylated and ubiquitinated Mis12 level with consequent reduction of Mis12, suggesting that BITC degrades Mis12 through an ubiquitin-proteasome system. Furthermore, cell cycle analysis showed that the change in the Mis12 level affected the cell cycle distribution and the sensitivity to the BITC-induced apoptosis. These results provide evidence that BITC suppresses cell proliferation through the post-transcriptional regulation of the kinetochore protein Mis12.

DOI： 10.1038/s41598-019-45248-2

Physiological relevance of covalent protein modification by dietary isothiocyanates Reviewed

Toshiyuki Nakamura, Naomi AbeKanoh, Yoshimasa Nakamura

Journal of Clinical Biochemistry and Nutrition 62 ( 1 ) 11 - 19 2018.1

Authorship：Last author,　Corresponding author Language：English Publisher：The Society for Free Radical Research Japan

Isothiocyanates (ITCs), naturally occurring in abundance in crucif erous vegetables, are the most wellstudied organosulfur com pounds having an electrophilic reactivity. ITCs have been accepted as major ingredients of these vegetables that afford their health promoting potentials. ITCs are able to modulate protein functions related to drugmetabolizing enzymes, transporters, kinases and phosphatases, etc. One of the most important questions about the molecular basis for the health promoting effects of ITCs is how they modulate cellular target proteins. Although the molec ular targets of ITCs remains to be validated, dietary modulation of the target proteins via covalent modification by ITCs should be one of the promising strategies for the protection of cells against oxidative and inflammatory damage. This review discusses the plausible target proteins of dietary ITCs with an emphasis on pos sible involvement of protein modification in their health promot ing effects. The fundamental knowledge of ITCs is also included with consideration of the chemistry, intracellular behavior, and metabolism.

DOI： 10.3164/jcbn.17-91

Flavonoid metabolism: the interaction of metabolites and gut microbiota Reviewed

Kaeko Murota, Yoshimasa Nakamura, Mariko Uehara

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 82 ( 4 ) 600 - 610 2018

Authorship：Lead author Language：English Publisher：TAYLOR & FRANCIS LTD

Several dietary flavonoids exhibit anti-oxidative, anti-inflammatory, and anti-osteoporotic activities relevant to prevention of chronic diseases, including lifestyle-related diseases. Dietary flavonoids (glycoside forms) are enzymatically hydrolyzed and absorbed in the intestine, and are conjugated to their glucuronide/sulfate forms by phase II enzymes in epithelial cells and the liver. The intestinal microbiota plays an important role in the metabolism of flavonoids found in foods. Some specific products of bacterial transformation, such as ring-fission products and reduced metabolites, exhibit enhanced properties. Studies on the metabolism of flavonoids by the intestinal microbiota are crucial for understanding the role of these compounds and their impact on our health. This review focused on the metabolic pathways, bioavailability, and physiological role of flavonoids, especially metabolites of quercetin and isoflavone produced by the intestinal microbiota.

DOI： 10.1080/09168451.2018.1444467

Benzyl isothiocyanate ameliorates acetaldehyde-induced cytotoxicity by enhancing aldehyde dehydrogenase activity in murine hepatoma Hepa1c1c7 cells Reviewed

Yujia Liu, Momoko Yamanaka, Naomi Abe-Kanoh, Xiaoyang Liu, Beiwei Zhu, Shintaro Munemasa, Toshiyuki Nakamura, Yoshiyuki Murata, Yoshimasa Nakamura

FOOD AND CHEMICAL TOXICOLOGY 108 305 - 313 2017.10

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

In the present study, we assessed benzyl isothiocyanate (BITC), an organosulfur compound from cruciferous vegetables, as a potential inducer of aldehyde dehydrogenase (ALDH) activity using murine hepatoma Hepa1c1c7 cells. BITC was shown to enhance not only the total ALDH activity, but also the ALDH activity of the cytosolic/microsomal and mitochondrial fraction. BITC also significantly increased the gene and protein expression of ALDH1A1, ALDH2 and ALDH3A1 in a concentration-dependent manner. Simultaneously, the gene expression of phase 2 drug-metabolizing enzymes, such as NAD(P)H: quinone oxidoreductase 1 and heme oxygenase-1, was increased by the BITC treatment. Western blot experiments revealed that BITC not only up-regulated the Nrf2 protein expression, but also stimulated the nuclear translocation of Nrf2. Furthermore, silencing Nrf2 reduced the basal and BITC-enhanced levels of the total activity and gene expression of ALDHs. The pretreatment of BITC completely mitigated the acetaldehyde-induced cytotoxicity, which was impaired by silencing Nrf2. The present study demonstrated that BITC has been identified as a potential inducer of the total ALDH activity to prevent the acetaldehyde-induced cytotoxicity. (C) 2017 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.fct.2017.08.016

3,4-Dihydroxyphenylacetic acid is a predominant biologically-active catabolite of quercetin glycosides Reviewed

Yue Tang, Sayaka Nakashima, Shunya Saiki, Yui Myoi, Naomi Abe, Shoko Kuwazuru, Beiwei Zhu, Hitoshi Ashida, Yoshiyuki Murata, Yoshimasa Nakamura

FOOD RESEARCH INTERNATIONAL 89 716 - 723 2016.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Since dietary flavonoid glycosides, including quercetin 4'-glucoside from onion, are poorly absorbed from the gastrointestinal tract, they are converted into smaller phenolic acids, which can be absorbed into the circulation. The purpose of this study was to compare the effects of the major phenolic acid catabolites of quercetin 4'-glucoside, including 3,4-dihydroxyphenylacetic acid (DOPAC), 3-hydroxyphenylacetic acid, 3,4-dihydroxybenzoic acid (protocatechuic acid) and hippuric acid, on the antioxidant activity and phase II cytoprotective enzyme induction in vitro. Both DOPAC and protocatechuic acid, having a catechol moiety, exhibited both DPPH radical scavenging and superoxide dismutase-like activities, whereas 3-hydroxyphenyl acetic acid and hippuric acid did not. DOPAC also more potently enhanced the gene expression of several phase II drug-metabolizing enzymes than the other phenolic acid catabolites. DOPAC significantly inhibited the hydrogen peroxide-induced cytotoxicity in hepatocytes with the enhancement of the total glutathione S-transferase activity. In conclusion, DOPAC may play a key role in the antioxidative potential of the colonic lumen after the ingestion of the quercetin glycoside-rich onion. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.foodres.2016.09.034

Nuclear factor-kappaB sensitizes to benzyl isothiocyanate-induced antiproliferation in p53-deficient colorectal cancer cells Reviewed

N. Abe, D-X Hou, S. Munemasa, Y. Murata, Y. Nakamura

CELL DEATH & DISEASE 5 2014.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

Benzyl isothiocyanate (BITC), a dietary isothiocyanate derived from cruciferous vegetables, inhibits the proliferation of colorectal cancer cells, most of which overexpress beta-catenin as a result of mutations in the genes for adenomatous polyposis coli or mutations in beta-catenin itself. Because nuclear factor-kappa B (NF-kappa B) is a plausible target of BITC signaling in inflammatory cell models, we hypothesized that it is also involved in BITC-inhibited proliferation of colorectal cancer cells. siRNA-mediated knockdown of the NF-kappa B p65 subunit significantly decreased the BITC sensitivity of human colorectal cancer HT-29 cells with mutated p53 tumor suppressor protein. Treating HT-29 cells with BITC induced the phosphorylation of I kappa B kinase, I kappa B-alpha and p65, the degradation of I kappa B-a, the translocation of p65 to the nucleus and the upregulation of NF-kappa B transcriptional activity. BITC also decreased alpha-catenin binding to a positive cis element of the cyclin D1 promoter and thus inhibited beta-catenin-dependent cyclin D1 transcription, possibly through a direct interaction between p65 and alpha-catenin. siRNA-mediated knockdown of p65 confirmed that p65 negatively affects cyclin D1 expression. On the other hand, when human colorectal cancer HCT-116 cells with wild-type p53 were treated with BITC, translocation of p65 to the nucleus was inhibited rather than enhanced. p53 knockout increased the BITC sensitivity of HCT-116 cells in a p65-dependent manner, suggesting that p53 negatively regulates p65-dependent effects. Together, these results identify BITC as a novel type of antiproliferative agent that regulates the NF-kappa B pathway in p53-deficient colorectal cancer cells.

DOI： 10.1038/cddis.2014.495

Electrophiles in Foods: The Current Status of Isothiocyanates and Their Chemical Biology Invited Reviewed

Yoshimasa Nakamura, Noriyuki Miyoshi

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 74 ( 2 ) 242 - 255 2010.2

Authorship：Lead author,　Corresponding author Language：English Publisher：TAYLOR & FRANCIS LTD

Unlike many classical signals and hormones, exposure of the cells to electrophilic molecules potentially induces a series of characteristic and wide-ranging biological responses by covalently attaching with macromolecules such as proteins as well as small cellular reductants. In addition to chemicals originated from xenobiotics or lipid peroxidation, electrophiles in foods have recently attracted much attention. These compounds have recently been found to induce expression of cytoprotective proteins that are involved in the elimination or inactivation of oxidative stress and carcinogenic electrophiles implicated in several pathogeneses. The redox-sensitive regulating systems such as Keap1/Nrf2/ARE play a key role in this induction and thus are considered to be the most important target of electrophiles in foods. This review highlights the food-derived electrophiles as promising protectors against various diseases, with an emphasis on possible molecular mechanisms. Current knowledge of isothiocyanates (ITCs), representative electrophile compounds from cruciferous vegetables, is discussed also, with consideration of the chemistry, metabolism, absorption, and factors influencing the biological activities of ITCs. In addition, this review attempts to provide a balanced perspective on the relative beneficial and harmful effects of the food electrophiles.

DOI： 10.1271/bbb.90731

JNK-dependent NFATc1 pathway positively regulates IL-13 gene expression induced by (-)-epigallocatechin-3-gallate in human basophilic KU812 cells Reviewed

Haitao Wu, Hang Qi, Dai Iwasaki, Beiwei Zhu, Yasuaki Shimoishi, Yoshiyuki Murata, Yoshimasa Nakamura

FREE RADICAL BIOLOGY AND MEDICINE 47 ( 7 ) 1028 - 1038 2009.10

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

(-)-Epigallocatechin-3-gallate (EGCG) has been reported to possess a wide range of biological and pharmacological properties. In this study, we investigated the effects of EGCG on IL-13 gene expression in human basophilic KU812 cells. The IL-13 mRNA expression level was dose-dependently increased by treatment with EGCG (5-20 mu M) for 1 h and additional incubation in a medium for 23 h. EGCG significantly increased the intracellular peroxide level as detected by the peroxide-sensitive probe 2',7'-dichlorodihydro-fluorescein diacetate. A pharmacological experiment using catalase and a structure-activity relationship study revealed that the exogenously produced H(2)O(2) significantly, but partially, contributed to the IL-13 expression as well as the intracellular oxidative status. Furthermore, EGCG at the concentration required for IL-13 up-regulation activated c-Jun NH(2)-terminal kinase (JNK), but not extracellular signal-regulated protein kinase or p38 mitogen-activated protein kinase in KU812 cells. Transfection of a JNK-specific siRNA as well as treatment with a JNK-specific inhibitor, SP600125, significantly reduced the EGCG-induced IL-13 mRNA expression, by 47.1 and 44.6%, respectively. In addition, we observed the nuclear translocation, mRNA up-regulation, and activation of DNA binding with the IL-13 promoter of nuclear factor of activated T cells (NFATc1) in the EGCG-treated cells. These data provide biological evidence that EGCG induces IL-13 mRNA expression via the JNK-dependent NFATc1 pathway in KU812 cells. (C) 2009 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.freeradbiomed.2009.07.011

Docosahexaenoic acid induces ERK1/2 activation and neuritogenesis via intracellular reactive oxygen species production in human neuroblastoma SH-SY5Y cells Reviewed

Haitao Wu, Sanae Ichikawa, Chiharu Tani, Beiwei Zhu, Mikiro Tada, Yasuaki Shimoishi, Yoshiyuki Murata, Yoshimasa Nakamura

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR AND CELL BIOLOGY OF LIPIDS 1791 ( 1 ) 8 - 16 2009.1

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Docosahexaenoic acid (22: 6n-3: DHA) is a long chain polyunsaturated fatty acid that exists highly enriched in fish oil, and it is one of the low molecular weight food chemicals which can pass a blood brain barrier. A preliminary survey of several fatty acids for expression of growth-associated protein-43 (GAP-43), a marker of axonal growth, identified DHA as one of the most potent inducers. The human neuroblastoma SH-SY5Y cells exposed to DHA showed significant and dose-dependent increases in the percentage of cells with longer neurites. To elucidate signaling mechanisms involved in DHA-enhanced basal neuritogenesis, we examined the role of extracellular signal-regulated kinase (ERK)1/2 and intracellular reactive oxygen species (ROS) production using SH-SY5Y cells. From immunoblotting experiments, we observed that DHA induced the ROS production, protein tyrosine phosphatase inhibition, mitogen-activated protein kinase (MAPK)/ERK kinase (MEK) phosphorylation, and sequentially ERK1/2 phosphorylation, the last of which was significantly reduced by MEK inhibitor U0126. Both antioxidants and MEK inhibitor affected DHA-induced GAP-43 expression, whereas the specific PI3K inhibitor LY294002 did not. We found that total protein tyrosine phosphatase activity was also downregulated by DHA treatment. which was counteracted by antioxidant pretreatment. These results suggest that the ROS-dependent ERK pathway, rather than PI3K, plays an important role during DHA-enhanced neurite outgrowth. (C) 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.bbalip.2008.10.004

ATP depletion alters the mode of cell death induced by benzyl isothiocyanate Reviewed

Noriyuki Miyoshi, Etsuko Watanabe, Toshihiko Osawa, Masashi Okuhira, Yoshiyuki Murata, Hiroshi Ohshima, Yoshimasa Nakamura

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE 1782 ( 10 ) 566 - 573 2008.10

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Pro-inflammatory death is presumably an undesirable event in cancer prevention process, thus biochemical comprehension and molecular definition of this process could have important clinical implications. In the present study, we examined the cytophysiological conversion of cell death mode by benzyl isothiocyanate (BITC) in human cervical cancer HeLa cells. The detailed studies using flow cytometric and morphological analyses demonstrated that the cells treated with appropriate concentration (25 mu M) of BITC showed apoptotic feature, such as chromatin condensation, DNA fragmentation, and preserved plasma membrane integrity, whereas these features were disappeared by treatment with higher concentration (100 mu M). The treatment with 2-deoxyglucose, an inhibitor of ATP synthesis, drastically increased in the ratio of necrotic dead cells, while it influences little that of apoptotic cells. Moreover, an analysis using the mitochondrial DNA-deficient HeLa cells demonstrated that the rho degrees cells were more susceptible to the BITC-induced necrosis-like cell death compared to the wild-type (rho(+)) cells, whereas the ROS production was significantly inhibited in the rho degrees cells. It is likely that the BITC-induced ROS is derived from mitochondrial respiratory chain and ruled out the contribution to the mechanism of cell death mode switching. In addition, the BITC treatment resulted in a more rapid depletion of ATP in the rho degrees cells than in the rho(+) cells. Furthermore. a caspase inhibitor, Z-VAD-fmk counteracted not only apoptosis, but also necrosis-like cell death induced by BITC, suggesting that increment in this cell death pattern might be due to the interruption of events downstream of a caspase-dependent pathway. The obtained data suggested that the decline in the intracellular ATP level plays an important role in tuning the mode of cell death by BITC. (C) 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.bbadis.2008.07.002

Reactive oxygen species and angiogenesis: NADPH oxidase as target for cancer therapy Invited Reviewed

Masuko Ushio-Fukai, Yoshimasa Nakamura

CANCER LETTERS 266 ( 1 ) 37 - 52 2008.7

Authorship：Last author Language：English Publisher：ELSEVIER IRELAND LTD

Angiogenesis is essential for tumor growth, metastasis, arteriosclerosis as well as embryonic development and wound healing. Its process is dependent on cell proliferation, migration and capillary tube formation in endothelia cells (ECs). High levels of reactive oxygen species (ROS) such as superoxide and H(2)O(2) are observed in various cancer cells. Accumulating evidence suggests that ROS function as signaling molecules to mediate various growth-related responses including angiogenesis. ROS-dependent angiogenesis can be regulated by endogenous antioxidant enzymes such as SOD and thioredoxin. Vascular endothelial growth factor (VEGF), one of the major angiogenesis factor, is induced in growing tumors and stimulates EC proliferation and migration primarily through the VEGF receptor type2 (VEGFR2, Flk1/KDR). Major source of ROS in ECs is a NADPH oxidase which consists of Nox1, Nox2, Nox4, Nox5, p22(phox), p47 (phox) and the small G-protein Rac1. NADPH oxidase is activated by various growth factors including VEGF and angiopoietin-1 as well as hypoxia and ischemia, and ROS derived from this oxidase are involved in VEGFR2 autophosphorylation, and diverse redox signaling pathways leading to induction of transcription factors and genes involved in angiogenesis. Dietary antioxidants appear to be effective for treatment of tumor angiogenesis. The aim of this review is to provide an overview of the recent progress on role of ROS derived from NADPH oxidase and redox signaling events involved in angiogenesis. Understanding these mechanisms may provide insight into the NADPH oxidase and redox signaling components as potential therapeutic targets for tumor angiogenesis (c) 2008 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.canlet.2008.02.044

Role of protein tyrosine phosphatase 1B in vascular endothelial growth factor signaling and cell-cell adhesions in endothelial cells Reviewed

Yoshimasa Nakamura, Nikolay Patrushev, Hyoe Inomata, Dolly Mehta, Norifumi Urao, Ha Won Kim, Masooma Razvi, Vidisha Kini, Kalyankar Mahadev, Barry J. Goldstein, Ronald McKinney, Tohru Fukai, Masuko Ushio-Fukai

CIRCULATION RESEARCH 102 ( 10 ) 1182 - 1191 2008.5

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：LIPPINCOTT WILLIAMS & WILKINS

Vascular endothelial growth factor (VEGF) binding induces phosphorylation of VEGF receptor (VEGFR) 2 in tyrosine, which is followed by disruption of VE-cadherin-mediated cell-cell contacts of endothelial cells (ECs), thereby stimulating EC proliferation and migration to promote angiogenesis. Tyrosine phosphorylation events are controlled by the balance of activation of protein tyrosine kinases and protein tyrosine phosphatases (PTPs). Little is known about the role of endogenous PTPs in VEGF signaling in ECs. In this study, we found that PTP1B expression and activity are markedly increased in mice hindlimb ischemia model of angiogenesis. In ECs, overexpression of PTP1B, but not catalytically inactive mutant PTP1B-C/S, inhibits VEGF-induced phosphorylation of VEGFR2 and extracellular signal-regulated kinase 1/2, as well as EC proliferation, whereas knockdown of PTP1B by small interfering RNA enhances these responses, suggesting that PTP1B negatively regulates VEGFR2 signaling in ECs. VEGF-induced p38 mitogen-activated protein kinase phosphorylation and EC migration are not affected by PTP1B overexpression or knockdown. In vivo dephosphorylation and cotransfection assays reveal that PTP1B binds to VEGFR2 cytoplasmic domain in vivo and directly dephosphorylates activated VEGFR2 immunoprecipitates from human umbilical vein endothelial cells. Overexpression of PTP1B stabilizes VE-cadherin-mediated cell-cell adhesions by reducing VE-cadherin tyrosine phosphorylation, whereas PTP1B small interfering RNA causes opposite effects with increasing endothelial permeability, as measured by transendothelial electric resistance. In summary, PTP1B negatively regulates VEGFR2 receptor activation via binding to the VEGFR2, as well as stabilizes cell-cell adhesions through reducing tyrosine phosphorylation of VE-cadherin. Induction of PTP1B by hindlimb ischemia may represent an important counterregulatory mechanism that blunts overactivation of VEGFR2 during angiogenesis in vivo.

DOI： 10.1161/CIRCRESAHA.107.167080

Papaya seed represents a rich source of biologically active isothiocyanate Reviewed

Yoshimasa Nakamura, Motoko Yoshimoto, Yoshiyuki Murata, Yasuaki Shimoishi, Yumi Asai, Eun Young Park, Kenji Sato, Yasushi Nakamura

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 55 ( 11 ) 4407 - 4413 2007.5

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

In the present study, papaya (Carica papaya) seed and edible pulp were carefully separated and then the contents of benzyl isothiocyanate and the corresponding glucosinolate (benzyl glucosinolate, glucotropaeolin) quantified in each part. The papaya seed with myrosinase inactivation contained > 1 mmol of benzyl glucosinolate in 100 g of fresh seed. This content is equivalent to that of Karami daikon (the hottest Japanese white radish) or that of cress. The papaya seed extract also showed a very high activity of myrosinase and, without myrosinase inactivation, produced 460 mu mol of benzyl isothiocyanate in 100 g of seed. In contrast, papaya pulp contained an undetectable amount of benzyl glucosinolate and showed no significant myrosinase activity. The n-hexane extract of the papaya seed homogenate was highly effective in inhibiting superoxide generation and apoptosis induction in HL-60 cells, the activities of which are comparable to those of authentic benzyl isothiocyanate.

DOI： 10.1021/jf070159w

Selective cytotoxicity of benzyl isothiocyanate in the proliferating fibroblastoid cells Reviewed

Noriyuki Miyoshi, Koji Uchida, Toshihiko Osawa, Yoshimasa Nakamura

INTERNATIONAL JOURNAL OF CANCER 120 ( 3 ) 484 - 492 2007.2

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-LISS

In the present study, experiments using presynchronization culture cells demonstrated that benzyl ITC (BITC), previously isolated from a tropical papaya fruit extract, induced the cytotoxic effect preferentially in the proliferating human colon CCD-18Co cells to the quiescent ones. Quiescent CCD-18Co cells were virtually unaffected by BITC and marginal cytotoxicity was observed at 15 mu M. We observed that BITC dramatically induced the p53 phosphorylation and stabilization only in the quiescent (G(0)/G(1) phase-arrested) cells, but not significantly in the proliferating human colon CCD-18Co cells when compared with quiescent ones. We also observed ataxia telangiectasia-mutated (ATM) phosphorylation in the quiescent cells. The BITC-induced p53 phosphorylation was counteracted by caffeine treatment, implying the involvement of an ATM/ataxia telangiectasia and Rad3-related kinase signaling pathway. Moreover, downregulation of p53 by a siRNA resulted in the enhancement of susceptibility to undergo apoptosis by BITC. We also showed here that depletion of p53 abrogated G(0)/G(1), arrest accompanied by the declined expression of p21(waf1/cip1) and p27(kip1) in CCD-18Co cells. In conclusion, we identified p53 as a potential negative regulator of the apoptosis induction by BITC in the normal colon CCD-18Co cells through the inhibition of cell-cycle progression at the G(0)/G(1) phase. (c) 2006 Wiley-Liss, Inc.

DOI： 10.1002/ijc.22350

Benzyl isothiocyanate inhibits excessive superoxide generation in inflammatory leukocytes: implication for prevention against inflammation-related carcinogenesis Reviewed

N Miyoshi, S Takabayashi, T Osawa, Y Nakamura

CARCINOGENESIS 25 ( 4 ) 567 - 575 2004.4

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Inhibitors of excessive superoxide (O-2(-)) generation have been indicated to be more effective antioxidants than radical scavengers because O-2(-) anion is one of the precursors of several types of reactive oxygen species (ROS). We demonstrated here that benzyl isothiocyanate (BITC) is a potent inhibitor of leukocytic NADPH oxidase generating a great amount of O-2(-) in oxidative burst. The exposure of BITC to the differentiated HL-60 cells resulted in the inhibition of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced O-2(-) generation, while the methylthiocarbamate analog of BITC, hardly reactive with thiols including glutathione and protein sulfhydryl, did not show any effect. Pre-treatment of the cells with diethyl maleate significantly potentiated the BITC-induced inhibition, while pre-treatment with N-acetyl-cysteine counteracted it. These results led us to assume that a plausible intracellular target molecule(s) having a reactive sulfhydryl moiety might be regulated by the covalent attachment with BITC. In spite of no ability to affect the translocation of protein kinase C beta to the membrane, BITC probably modifies the electron transport system of cytochrome b(558), consistent with the observation that BITC inhibited the substrate utilization. Pre-treatments of mouse skin with BITC significantly attenuated the TPA-enhanced hydrogen peroxide level, suggesting that BITC indeed acts as an inhibitor of O-2(-) generation in mouse skin. A histological study also demonstrated that BITC inhibited TPA-induced leukocyte infiltration in the dermis. Because we have found several O-2(-) generation inhibitors to be effective chemopreventors against mouse skin carcinogenesis, the modifying effect of the topical application of BITC on TPA-induced mouse skin tumor promotion was investigated. We demonstrated for the first time that the pre-treatment with BITC 40 min prior to each TPA treatment significantly inhibited the number of papillomas per mouse. In conclusion, the results from this study provided biological evidence that BITC has a potential to prevent inflammation-related carcinogenesis including skin cancer.

DOI： 10.1093/carcin/bgh051

A link between benzyl isothiocyanate-induced cell cycle arrest and apoptosis: Involvement of mitogen-activated protein kinases in the Bcl-2 phosphorylation Reviewed

N Miyoshi, K Uchida, T Osawa, Y Nakamura

CANCER RESEARCH 64 ( 6 ) 2134 - 2142 2004.3

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ASSOC CANCER RESEARCH

In the present study, we clarified the molecular mechanism underlying the relationship between benzyl isothiocyanate (BITC)-induced cell cycle arrest and apoptosis and the involvement of mitogen-activated protein kinases (MAPKs). The exposure of Jurkat human T-cell leukemia cells to BITC resulted in the inhibition of the G(2)-M progression that coincided with the apoptosis induction. The experiment using the phase-specific synchronized cells demonstrated that the G(2)-M phase-arrested cells are more sensitive to undergoing apoptotic stimulation by BITC than the cells in other phases. We also confirmed that BITC activated c-Jun N-terminal kinase (JNK) and p38 MAPK, but not extracellular signal-regulated kinase, at the concentration required for apoptosis induction. An experiment using a JNK-specific inhibitor SP600125 or a p38 MAPK inhibitor SB202190 indicated that BITC-induced apoptosis might be regulated by the activation of these two kinases. Conversely, BITC is likely to confine the Jurkat cells in the G(2)-M phase mainly through the p38 MAPK pathway because only the p38 MAPK inhibitor significantly attenuated the accumulation of inactive phosphorylated Cdc2 protein and the G(2)-M- arrested cell numbers. We reported here for the first time that the antiapoptotic Bcl-2 protein was phosphorylated by the BITC treatment without significant alteration of the Bcl-2 total protein amount. This was abrogated by a JNK specific inhibitor SP600125 at the concentration required for specific inhibition of the c-Jun phosphorylation. Moreover, the spontaneous phosphorylation of antiapoptotic Bcl-2 in the G(2)-M synchronized cells was enhanced synergistically by the BITC treatment. Involvement of the MAPK activation in the Bcl-2 phosphorylation and apoptosis induction also was observed in HL-60 and HeLa cells. Thus, we identified the phosphorylated Bcl-2 as a key molecule linking the p38 MAPK-dependent cell cycle arrest with the JNK activation by BITC.

DOI： 10.1158/0008-5472.CAN-03-2296

Arachidonic acid cascade inhibitors modulate phorbol ester-induced oxidative stress in female ICR mouse skin: Differential roles of 5-lipoxygenase and cyclooxygenase-2 in leukocyte infiltration and activation Reviewed

Y Nakamura, M Kozuka, K Naniwa, S Takabayashi, K Torikai, R Hayashi, T Sato, H Ohigashi, T Osawa

FREE RADICAL BIOLOGY AND MEDICINE 35 ( 9 ) 997 - 1007 2003.11

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

We recently developed a short-term assay for skin H2O2 generation induced by double 12-O-tetradecanoylphorbol-13-acetate (TPA) applications for mechanistic study on skin epidermal carcinogenesis. In the present study, we investigated the individual roles of arachidonic acid metabolism in H2O2 generation in mouse skin inflammation. The experiments using inhibitors of arachidonic acid (AA) metabolism showed that corticosteroid and a lipoxygenase (LO) inhibitor expectedly suppressed double TPA application-induced H2O2 generation through the interference of chemotactic action but not by direct decomposition or scavenging. We also demonstrated that the treatment of AA (1 mumol) and 5-LO metabolites including leukotriene B-4 (LTB4) partly mimicked, though soybean LO-derived lipid hydroperoxide and prostaglandins did not, the priming effect evaluated by edema formation and leukocyte infiltration. We also confirmed that inflammatory leukocytes accumulated by LTB4 generated a significant amount of H2O2 by TPA stimulation. These results suggested that 5-LO metabolites of AA are the potential key molecules in the TPA-induced priming event. Interestingly, the cyclooxygenase (COX-) 2-selective inhibitor nimesulide (NS) and celecoxib (CXB) showed different responses than those of other inhibitors. These agents showed no specific potential to inhibit the priming event but significantly suppressed H2O2 generation, lipid peroxidation, and hyperplasia in mouse skin. From the results based on an in vitro leukocyte differentiation model, we speculated that the antioxidant effect of the COX-2 inhibitors might be partly associated with both counteraction of proinflammatory cytokine-enhanced ROS generation and inhibition of CD11b, an important molecule for cell adhesion, expression. Indeed, the topical application of NS attenuated the number of infiltrated leukocytes induced by TPA in mouse skin. Thus, these gathered data indicated the differential roles of 5-LO and COX-2 in leukocyte adhesion, infiltration, and H2O2 generation. (C) 2003 Elsevier Inc.

DOI： 10.1016/S0891-5849(03)00440-4

Pivotal role of electrophilicity in glutathione S-transferase induction by tert-butylhydroquinone Reviewed

Y Nakamura, T Kumagai, C Yoshida, Y Naito, M Miyamoto, H Ohigashi, T Osawa, K Uchida

BIOCHEMISTRY 42 ( 14 ) 4300 - 4309 2003.4

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Although the induction of glutathione S-transferase (GST) activity by tert-butylhydroquinone (tBHQ) has been well-documented in several cell culture systems and rodent experiments, the exact mechanism responsible for its inducibility is still not thoroughly understood. To more precisely define the molecular mechanism of GST induction by tBHQ, we examined the one-electron oxidation and glutathione (GSH) reaction potentials of tBHQ as compared to its analogue, 2,5-di-tert-butylhydroquinone (DtBHQ). tBHQ and DtBHQ showed similar one-electron oxidation potentials, including free radical quenching (antioxidant), oxidative conversion of both compounds to a benzoquinone form, and Cu2+-dependent superoxide generation. On the other hand, the reduced GSH level was observed by the addition of tBHQ, but not DtBHQ, suggesting that tBHQ acts as an electrophile while DtBHQ does not. The data were consistent with the observation that tBHQ more potently induced the GSTP1 gene expression in RL34 cells than DtBHQ did. Moreover, we indeed detected the GSH-tBHQ conjugates in the cells exposed to tBHQ using an electrochemical detector-high-performance liquid chromatography technique. Thus, we conclude that an electrophilic quinone oxidation product that reacts with intracellular nucleophiles including protein thiol or GSH plays a major role in the GSTP1 gene expression.

DOI： 10.1021/bi0340090

Involvement of the mitochondrial death pathway in chemopreventive benzyl isothiocyanate-induced apoptosis Reviewed

Y Nakamura, M Kawakami, A Yoshihiro, N Miyoshi, H Ohigashi, K Kawai, T Osawa, K Uchida

JOURNAL OF BIOLOGICAL CHEMISTRY 277 ( 10 ) 8492 - 8499 2002.3

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

In the present study, we studied the molecular mechanism underlying cell death induced by a cancer chemoprotective compound benzyl isothiocyanate (BITC). The cytotoxic effect of BITC was examined in rat liver epithelial RL34 cells. Apoptosis was induced when the cells were treated with 20 muM BITC, characterized by the appearance of phosphatidylserine on the outer surface of the plasma membrane and caspase-3 activation, whereas no caspase activation and propidium iodide incorporation into cell were detected with 50 muM BITC that induced necrosis. The mitochondrial death pathway was suggested to be involved in BITC-induced apoptosis because the treatment of cells with BITC-induced caspase-9-dependent apoptosis and mitochondrial transmembrane potential (DeltaPsim) alteration. We demonstrated here for the first time that BITC directly modifies mitochondrial functions, including inhibition of respiration, mitochondrial swelling, and release of cytochrome c. Moreover, glutathione depletion by diethyl maleate significantly accelerated BITC-triggered apoptosis, suggesting the involvement of a redox-dependent mechanism. This was also implicated by the observations that intracellular accumulation of reactive oxygen species, including superoxide (O-2(.-)) and hydroperoxides (HPOs), was indeed detected in the cells treated with BITC and that the intracellular HPO level was significantly attenuated by pretreatment with N-ace-tylcysteine. The treatment with a pharmacological scavenger of 07 Tiron, also diminished the HPO formation by similar to80%,c, suggesting that most of the HPOs were H2O2 derived from the dismutation of O-2(.-). These results suggest that BITC induces apoptosis through a mitochondial redox-sensitive mechanism.

DOI： 10.1074/jbc.M109760200

Ebselen, a glutathione peroxidase mimetic seleno-organic compound, as a multifunctional antioxidant - Implication for inflammation-associated carcinogenesis Reviewed

Y Nakamura, Q Feng, T Kumagai, K Torikai, H Ohigashi, T Osawa, N Noguchi, E Niki, K Uchida

JOURNAL OF BIOLOGICAL CHEMISTRY 277 ( 4 ) 2687 - 2694 2002.1

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Ebselen, a seleno-organic compound showing glutathione peroxidase-like activity, is one of the promising synthetic antioxidants. In the present study, we investigated the antioxidant activities of ebselen using a 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated mouse skin model. Double pretreatments of mouse skin with ebselen significantly inhibited TPA-induced formation of thiobarbituric acid-reacting substance, known as an overall oxidative damage biomarker, in mouse epidermis, suggesting that ebselen indeed acts as an antioxidant in mouse skin. The andoxidative effect of ebselen is attributed to its selective blockade of leukocyte infiltration and activation leading to attenuation of the H2O2 level. In in vitro studies, ebselen inhibited TPA-induced superoxide generation in differentiated HL-60 cells and lipopolysaccharide-induced cyclooxygenase-2 protein expression in RAW 264.7 cells. In addition, we demonstrated for the first time that ebselen potentiated phase II enzyme activities, including NAD(P)H:(quinone-acceptor) oxidoreductasel and glutathione S-transferase in cultured hepatocytes and in mouse skin. These results strongly suggest that ebselen, a multifunctional antioxidant, is a potential chemopreventive agent in inflammation-associated carcinogenesis.

DOI： 10.1074/jbc.M109641200

A catechol antioxidant protocatechuic acid potentiates inflammatory leukocyte-derived oxidative stress in mouse skin via a tyrosinase bioactivation pathway Reviewed

Y Nakamura, K Torikai, H Ohigashi

FREE RADICAL BIOLOGY AND MEDICINE 30 ( 9 ) 967 - 978 2001.5

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

The modifying effects of topical application of a catechol antioxidant protocatechuic acid (PA) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammatory responses in mouse skin were investigated. Treatment with a high dose (20,000 nmol) of PA, based on time of application, modifies inflammatory responses in the skin of the B6C3F(1) mouse, a resistant strain to inflammatory response induction by TPA, but shows much higher tyrosinase expression than that of an albino mouse. The responsibility of a large amount of PA-induced leukocyte infiltration to an inflamed region in a B6C3F(1) mouse is mon sensitive than that of an ICR albino mouse. When ICR mice were treated with TPA (1.6 nmol) twice weekly for 5 weeks to induce chronic inflammatory responses, pretreatment with 1600 nmol PA 30 min prior to each TPA treatment significantly enhanced the inflammatory responses including edema formation, leukocyte infiltration, and the level of thiobarbituric acid-reacting substances. The dose-dependency was closely parallel to the results of a tumor promotion study of PA previously reported. Further, the treatment of PA alone resulted in tyrosinase-dependent contact hypersensitivity in ICR mouse skin. In addition, the in vitro study of cytotoxicity demonstrated that bioactivation by tyrosinase but not myeloperoxidase of PA significantly enhanced cytotoxicity and intracellular glutathione consumption. We conclude that the tyrosinase-derived reactive quinone intermediate(s) of PA, which binds nucleophilic residues of proteins including sulfhydryl group and conjugates of which are recognized as haptens, was partially involved in alteration of the cellular immune functions including oxygen radical-generating leukocytes migration to inflamed regions. (C) 2001 Elsevier Science Inc.

DOI： 10.1016/S0891-5849(01)00481-6

A simple phenolic antioxidant protocatechuic acid enhances tumor promotion and oxidative stress in female ICR mouse skin: dose- and timing-dependent enhancement and involvement of bioactivation by tyrosinase Reviewed

Y Nakamura, K Torikai, Y Ohto, A Murakami, T Tanaka, H Ohigashi

CARCINOGENESIS 21 ( 10 ) 1899 - 1907 2000.10

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

The modifying effects of topical application of the phenolic antioxidant protocatechuic acid (PA) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse skin tumor promotion were investigated. Dimethylbenz[a]anthracene-initiated female ICR mice were treated with TPA (1.6 nmol) twice weekly for 20 weeks to promote papilloma formation. Pre-treatment with 16 nmol PA 30 min prior to each TPA treatment significantly inhibited the number of papillomas per mouse by 52% (P < 0.05). On the other hand, PA pre-treatment at a high dose (1600 nmol) significantly enhanced tumor numbers by 38% (P < 0.05). Interestingly, in the group treated with a quite high dose (20000 nmol) of PA 5 min prior to each TPA application, the average number of tumors per mouse was reduced by 38%, whereas the same PA dose 3 h before TPA treatment significantly enhanced tumor numbers by 84% (P < 0.01). These results suggested that topically applied PA was converted to compound(s) lacking antioxidative properties and/or rather possessing the potential to enhance tumor development. A similar tendency was also observed in the short-term experiment of TPA-induced inflammation and oxidative stress; i.e. two groups pretreated with PA at 20 000 nmol, 30 min and 3 h before TPA treatment, did not show suppression or even significantly enhanced TPA-induced leukocyte infiltration, H2O2 generation, thiobarbituric acid-reacting substances level and proliferating cell nuclear antigen index, while PA treatment together with TPA significantly suppressed these parameters. Treatment with a high dose (20 000 nmol) of PA alone for 3 h enhanced oxidative stress by reducing glutathione levels in mouse skin, which was counteracted by the tyrosinase inhibitor arbutin, Oxidative stress responses such as leukocyte infiltration and H2O2 generation were also counteracted by arbutin, These results suggested that tyrosinase-dependent oxidative metabolism of PA was at least partially involved in the enhanced effects of PA on TPA-induced inflammatory responses and thus tumor promotion.

DOI： 10.1093/carcin/21.10.1899

A glutathione S-transferase inducer from papaya, rapid screening, identification and structure-activity relationship of isothiocyanates Reviewed

Y Nakamura, Y Morimitsu, T Uzu, H Ohigashi, A Murakami, Y Naito, Y Nakagawa, T Osawa, K Uchida

CANCER LETTERS 157 ( 2 ) 193 - 200 2000.9

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI IRELAND LTD

We have developed a simple system for rapid detection and measurement of glutathione S-transferase placental form (GSTP1) that detoxify polycyclic aromatic hydrocarbons using the cultured rat normal liver epithelial cell line, (RL34) cells. Survey of fruit extracts for GST inducing ability identified both papaya and avocado as significant sources. Benzyl isothiocyanate (BITC) was isolated from papaya methanol extract as a principal inducer of GST activity. Further, the GST inducing ability of a total of 20 isothiocyanates (ITCs) and their derivatives was investigated. Some ITCs showed significant induction, and BITC was one of the most potent inducers among all compounds tested in the present study. The modification of isothiocyanate group (-NCS) or introduction of substituent group to the a-carbon modifies GST induction. Moreover, a significant correlation (P < 0.01, r = 0.913) between the GST activity enrichment and GSTP1 protein induction by ITCs was observed. We also indicated that phenethyl ITC and nitrophenyl ITC, potently inducing GST activity, but not inactive benzyl isocyanate, are potential inducers of intracellular reactive oxygen intermediates (ROIs). Our system of GSTP1 induction is appropriate for the chemical research such as screening and identification of novel type of inducers as well as the structure-activity relationship studies, providing mechanistic insight into essential structural elements for GSTP1 induction. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.

DOI： 10.1016/S0304-3835(00)00487-0

Redox regulation of glutathione S-transferase induction by benzyl isothiocyanate: Correlation of enzyme induction with the formation of reactive oxygen intermediates Reviewed

Y Nakamura, H Ohigashi, S Masuda, A Murakami, Y Morimitsu, Y Kawamoto, T Osawa, M Imagawa, K Uchida

CANCER RESEARCH 60 ( 2 ) 219 - 225 2000.1

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ASSOC CANCER RESEARCH

Here we report the molecular mechanism underlying the induction of glutathione S-transferase (GST) in rat liver epithelial RL34 cells treated with a cancer chemopreventive isothiocyanate compound, benzylisothiocyanate (BITC), BITC was found to significantly induce GST activity in RL34 cells. Northern and Western blot analyses demonstrated that BITC specifically enhanced the production of the class pi GST isozyme (GSTP1), Our studies demonstrated for the first time that the addition of BITC to the cells resulted in an immediate increase in the reactive oxygen intermediates (ROIs) detected by a fluorescence probe, 2',7'-dichlorofluorescin diacetate. The level of the ROIs in the cells treated with BITC (10 mu M) was similar to 50-fold higher than those in the control cells. Furthermore, glutathione depletion by diethyl maleate significantly enhanced BITC-induced ROI production and accelerated the BITC-induced elevation of the GST activity, whereas pretreatment of the cells with glutathione inhibited both the ROI production and GST induction. The structure-activity relationship of the isothiocyanates also indicated that the ROI-producing activities closely correlated with their GST-inducing potencies. Moreover, the GSTP1 enhancer I-containing region was found to be essential for induction of the GSTP1 gene by intracellular ROI inducers such as BITC and diethyl maleate. These data suggest the involvement of the redox regulation on the induction of GSTP1 by BITC.

Suppression of tumor promoter-induced oxidative stress and inflammatory responses in mouse skin by a superoxide generation inhibitor 1 '-acetoxychavicol acetate Reviewed

Y Nakamura, A Murakami, Y Ohto, K Torikai, T Tanaka, H Ohigashi

CANCER RESEARCH 58 ( 21 ) 4832 - 4839 1998.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ASSOC CANCER RESEARCH

Double applications of phorbol eaters trigger excessive reactive oxygen species (ROS) production in mouse skin. previously reported data suggest that the two applications induce distinguishable biochemical events, namely, priming and activation. The former is characterized as a recruitment of inflammatory cells, such as neutrophils, by chemotactic factors to inflammatory regions and edema formation. The latter is responsible for ROS generation. Thus, inhibitory effects of 1'-acetoxychavicol acetate (ACA), previously reported to be a superoxide generation inhibitor is vitro, on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced oxidative stress and inflammatory responses in mouse skin model were examined using a double application of ACA. We demonstrated that two pretreatments and pretreatment with ACA (810 mmol) in the activation phase suppressed double TPA application-induced H2O2 formation in mouse skin, ACA exhibited no inhibitory effects on edema formation and the enhancement of myeloperoxidase activity during the first TPA treatment, whereas the anti-inflammatory agent genistein administered at the same dose inhibited both biomarkers, No inhibitory potential of ACA for TPA-induced H2O2 formation in the priming phase was confirmed. On the other hand, in the in vitro study, ACA inhibited ROS generation in differentiated HL-60 cells more strongly than did 1'-hydroxychavicol, which showed no inhibition by pretreatment in the activation phase In addition, allopurinol did not inhibit double TPA application-induced H2O2 formation in mouse skin, These findings suggest that the NADPH oxidase system of neutrophils rather than the epithelial xanthine oxidase system is dominant for the O-2(-)-generating potential in double TPA-treated mouse skin. ACA significantly inhibited mouse epidermis thiobarbituric acid-reacting substance formation, known as an overall oxidative damage biomarker, Moreover, histological studies demonstrated that ACA inhibited double TPA treatment-induced morphological changes reflecting inflammatory response, such as edema formation, leukocyte infiltration, hyperplasia, and cell proliferation. Furthermore, pretreatment with ACA but not 1'-hydroxychavicol in the activation phase inhibits double TPA application-induced increases in both number of leukocytes and proliferating cell nuclear antigen index. These results suggested that ROS from leukocytes including O-2(-) plays an important role for continuous and excessive production of chemotactic factors, leading to chronic inflammation and hyperplasia, which are inhibitable by ACA. Thus, we concluded that O-2(-) generation inhibitors are agents that effectively inhibit oxidative stress and inflammatory responses in mouse skin.

Inhibitory effects of curcumin and tetrahydrocurcuminoids on the tumor promoter-induced reactive oxygen species generation in leukocytes in vitro and in vivo Reviewed

Yoshimasa Nakamura, Yoshimi Ohto, Akira Murakami, Toshihiko Osawa, Hajime Ohigashi

Japanese Journal of Cancer Research 89 ( 4 ) 361 - 370 1998

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Cancer Association

The inhibitory effects of curcumin and two tetrahydrocurcuminoids on tumor promoter-induced oxidative stress in vitro and in vivo were investigated. Curcumin, tetrahydrocurcumin (THC) and dihydroxytetrahydrocurcumin (DHTHC) exhibited significant inhibitory effects on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced O2 - generation in differentiated HL-60 cells. The inhibitory activity of THC was weaker than that of curcumin. This tendency was the inverse of the results of previous studies on in vitro antioxidative activity against lipid peroxidation. The curcuminoids inhibited TPA-induced intracellular peroxide formation in differentiated HL-60 cells. THC exhibited much weaker inhibition of intracellular peroxide formation than curcumin, suggesting that this inhibition might be attributable to the inhibition of O2 - generation. The inhibitory effects of curcuminoids on TPA-induced H2O2 formation in female ICR mouse skin were further examined using the double-TPA-application model. Each TPA application induces two distinct biochemical events, 1) recruitment of inflammatory cells to the inflammatory regions and 2) activation of oxidant-producing cell. Double pretreatment of mice with curcuminoids before each TPA treatment significantly suppressed double TPA application-induced H2O2 formation in the mouse skin. Coadministrations of curcumin with either first or second TPA treatment significantly inhibited H2O2 formation. In addition, THC tends to show weaker inhibitory activities than curcumin in bioassays related to tumor promotion, i.e., inhibition of tumor promoter-induced inflammation in mouse skin and Epstein-Barr virus activation. These tendencies were parallel to those in the tumor-suppressive potential of curcumin and THC in mouse skin, as previously reported. Thus, we concluded that curcuminoids significantly suppress TPA-induced oxidative stress via both interference with infiltration of leukocytes into the inflammatory regions and inhibition of their activation.

DOI： 10.1111/j.1349-7006.1998.tb00572.x

Inhibitory effect of pheophorbide a, a chlorophyll-related compound, on skin tumor promotion in ICR mouse Reviewed

Y Nakamura, A Murakami, K Koshimizu, H Ohigashi

CANCER LETTERS 108 ( 2 ) 247 - 255 1996.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI IRELAND LTD

Anti-tumor-promoting activity of pheophorbide a (PPBa), a chlorophyll-related compound, was examined in a two-stage carcinogenesis experiment in ICR mouse skin by 7,12-dimethylbenz[a]anthracene (DMBA, 0.19 mu mol) and 12-O-tetradecanoylphorbol-13-acetate (TPA, 1.6 nmol). Topical application of PPBa (160 nmol) markedly reduced the average number of tumors per mouse and the ratio of tumor-bearing mice (inhibitory ratio: IR = 56%, P < 0.01 and 31%, P < 0.005, respectively). PPBa exhibited potent anti-inflammatory activity in ICR mouse ears and moderate inhibitory activity toward TPA-induced superoxide (O-2(-)) generation in differentiated HL-60 cells. While CuPPBa, a synthetic copper complex of PPBa, exhibited higher anti-inflammatory activity than that of indomethacin, it showed little antioxidative effect against formation of lipid hydroperoxides (LOOHs) and malondialdehyde (MDA), suggesting that the antioxidative effect of PPBa might not be important for anti-inflammatory activity. These results imply that the active mechanism of PPBa for anti-tumor promotion might be partly involved in inhibition of TPA-induced inflammatory responses by suppressing leukocyte activation.

DOI： 10.1016/S0304-3835(96)04422-9

Involvement of reactive carbonyl species in inhibition of germination and seedling growth by salt stress in rice Invited

Faruk Hossain Khan, Yoshitaka Nakashima, Toshiyuki Nakamura, Yoshimasa Nakamura, Yoshihiko Hirai, Md Anamul Hoque, Mohammad Saidur Rhaman, Shintaro Munemasa, Jun'ichi Mano, Yoshiyuki Murata

Bioscience, Biotechnology, and Biochemistry 2025.5

Proteome analysis reveals the molecular mechanisms of fucoxanthin-induced apoptosis in glial cells PC12 after nanoencapsulation Reviewed

Chunyan Wang, Xinxin Ma, Yoshimasa Nakamura, Hang Qi

Journal of Functional Foods 126 2025.3

Publishing type：Research paper (scientific journal)

Fucoxanthin (FX) is a natural pigment belonging to the xanthophyll carotenoid, which has been proven to have inhibitory effects on glioblastoma. In our previous study, nano-FX was fabricated through whey protein and flaxseed gum co-encapsulated for improved stability and glial cell (PC12) inhibitory activity of FX. To investigate the molecular mechanisms of FX-induced apoptosis in PC12 after nanoencapsulation, proteomics analysis based on TMT technology was performed. Protein profiles in PC12 were determined after 0 (Control), 8 (L_Treat), and 24 (H_Treat) μg/mL nano-FX intervention. Results indicated 78 differential abundant proteins (DAPs) linked to the cytotoxicity of nano-FX could be potential biomarkers. GO and KEGG analysis revealed altered proteasome and NF-kappa B/MAPK/TNF. Proteins involved in cell proliferation were downregulated, while proteins response to autophagy and apoptosis were upregulated. The multiple mechanisms involved in the anti-tumor activity of nano-FX will provide a reference for the development of FX high value-added functional foods.

DOI： 10.1016/j.jff.2025.106710

Fraglide-1 from traditional Chinese aromatic vinegar: A natural AhR antagonist for atopic dermatitis. Reviewed International journal

Kosuke Kato, Miki Akamatsu, Saya Kakimaru, Mayuko Koreishi, Masahiro Takagi, Masahiro Miyashita, Yoshiyuki Murata, Yoshimasa Nakamura, Ayano Satoh, Yoshio Tsujino

Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association 115301 - 115301 2025.2

Language：English Publishing type：Research paper (scientific journal)

Traditional Chinese Zhenjiang aromatic vinegar (Kozu) contains Fraglide-1 (FG1), a bioactive lactone with demonstrated peroxisome proliferator-activated receptor gamma (PPARγ) agonist and antioxidant activities. This study explored FG1's novel ability to antagonize the aryl hydrocarbon receptor (AhR) signaling pathway, which regulates artemin expression and contributes to itching and inflammation in atopic dermatitis. Through molecular docking simulations and cell-based assays in human keratinocytes, we demonstrated FG1's potent antagonistic activity against AhR signaling. FG1 effectively suppressed FICZ-induced inflammatory responses, including artemin expression, with potency (half maximal inhibitory concentration, IC50 = 5.1 μM) comparable to the synthetic antagonist StemRegenin 1 (SR1) while demonstrating a superior safety profile (median lethal concentration, LC50 > 100 μM vs. 27.5 μM for SR1). These findings expand our understanding of bioactive compounds from traditional fermented foods and their regulatory effects on AhR signaling, providing a foundation for future studies on FG1's role in modulating skin inflammation.

DOI： 10.1016/j.fct.2025.115301

Dual role of cytosolic GSH in the ABA signaling pathway and plasma membrane ion channel regulation in guard cells of Vicia faba. Reviewed International journal

Huifei Yin, Toshiyuki Nakamura, Yoshimasa Nakamura, Shintaro Munemasa, Yoshiyuki Murata

Journal of plant physiology 306 154447 - 154447 2025.2

Language：English Publishing type：Research paper (scientific journal)

Abscisic acid (ABA) induces stomatal closure in higher plants under drought stress. Glutathione (GSH) negatively regulates ABA-induced stomatal closure and reactive carbonyl species (RCS) play a role as signal mediators downstream of reactive oxygen species production in ABA signaling pathway in Arabidopsis thaliana. Activation of slow (S-type) anion channels and inhibition of inward-rectifying potassium ion (Kin+) channels in the plasma membrane are essential for ABA-induced stomatal closure. However, there is limited evidence regarding role of GSH in the activation of S-type anion channels and the inhibition of Kin+ channels. We used Vicia faba to clarify the regulation of these ion channels by GSH and RCS. Pretreatment of guard-cell protoplasts with the GSH-supplementing agent, glutathione monoethyl ester (GSHmee), suppressed the activation of S-type anion channels and the inactivation of Kin+ channels induced by ABA. The pretreatment with the RCS scavenger carnosine suppressed the activation of S-type anion channels and the inactivation of Kin+ channels by ABA. On patch clamping guard-cell protoplasts, the addition of GSH to the pipette (cytosolic) buffer decreased the S-type anion currents and increased the Kin+ currents. These results suggest that cytosolic GSH is involved in ABA-induced stomatal closure via negative regulation of ABA signaling and via direct regulation of ion channel activities in V. faba.

DOI： 10.1016/j.jplph.2025.154447

TGG1 and TGG2 mutations impair allyl isothiocyanate-mediated stomatal closure in Arabidopsis thaliana. Reviewed International journal

Kadri Oumaima, Mohammad Shakhawat Hossain, Wenxiu Ye, Eiji Okuma, Mohammad Issak, Mohammad Mahbub Islam, Misugi Uraji, Yoshimasa Nakamura, Izumi C Mori, Shintaro Munemasa, Yoshiyuki Murata

Protoplasma 2025.2

Language：English Publishing type：Research paper (scientific journal)

Myrosinase, referred to as thioglucoside glucohydrolase (TGG), plays a crucial role in plant physiology through catalyzing the hydrolysis of glucosinolates into bioactive isothiocyanates. In Arabidopsis thaliana, the myrosinases TGG1 and TGG2 are essential for abscisic acid- and methyl jasmonate-induced stomata closure. Allyl isothiocyanate (AITC), one of myrosinase products, triggers stomatal closure in A. thaliana. We investigated stomatal responses to AITC to clarify the role of TGG1 and TGG2 in Arabidopsis guard-cell signaling. Allyl isothiocyanate at 50 μM and 100 μM induced stomatal closure in the tgg1 and tgg2 single mutants but not in the tgg1 tgg2 double mutant. Furthermore, AITC at 50 μM induced the production of reactive oxygen species and nitric oxide, cytosolic alkalization, and oscillations in cytosolic free calcium concentration in guard cells of both wild-type and mutant plants. These findings suggest that TGG1 and TGG2 are involved in AITC signaling pathway through interaction with signal component(s) downstream of these signaling events, which is not accompanied by hydrolysis of glucosinolates because of the difference in subcellular localization between enzymes (myrosinases) and substrates (glucosinolates).

DOI： 10.1007/s00709-025-02039-z

Resveratrol, a food-derived polyphenol, promotes Melanosomal degradation in skin fibroblasts through coordinated activation of autophagy, lysosomal, and antioxidant pathways Reviewed

Saki Okamoto, Saya Kakimaru, Mayuko Koreishi, Mika Sakamoto, Yoshimasa Nakamura, Hideya Ando, Yoshio Tsujino, Ayano Satoh

Journal of Functional Foods 125 2025.2

Language：English Publishing type：Research paper (scientific journal)

Resveratrol, a polyphenol found in grapes and peanuts, is known for diverse biological activities, yet its effects on dermal hyperpigmentation (so-called dark spots) remain unexplored. We investigated resveratrol's ability to enhance melanosomal degradation in human dermal fibroblasts. At concentrations of 25–50 μM, resveratrol increased autophagy as measured by microtubule-associated protein 1A/1B-light chain 3 (LC3)-II/LC3-I ratio and enhanced lysosomal activity as assessed by a lysosomal activity reporter system. RNA sequencing revealed upregulation of lysosomal and autophagy-related genes, including cathepsins. Furthermore, reporter assays showed resveratrol's activation of antioxidant response via nuclear factor erythroid 2-related factor 2 (NRF2)-mediated, leading to upregulation of transcription factor EB/transcription factor E3 (TFEB/TFE3), master regulators of lysosomal function. In fibroblasts pre-loaded with melanosomes, resveratrol reduced melanosome content compared to control by day 3. The findings reveal the activation of interconnected autophagy, lysosomal, and antioxidant pathways by resveratrol, suggesting potential applications in functional foods targeting dermal hyperpigmentation.

DOI： 10.1016/j.jff.2025.106672

Reactive carbonyl species function downstream of reactive oxygen species in chitosan-induced stomatal closure. Reviewed International journal

Israt Jahan, Md Moshiul Islam, Toshiyuki Nakamura, Yoshimasa Nakamura, Shintaro Munemasa, Jun'ichi Mano, Yoshiyuki Murata

Physiologia plantarum 177 ( 1 ) e70094 2025

Language：English Publishing type：Research paper (scientific journal)

An elicitor, chitosan (CHT), induces stomatal closure in plants, which is accompanied by salicylhydroxamic acid (SHAM)-sensitive peroxidases-mediated reactive oxygen species (ROS) production in guard cells. Reactive carbonyl species (RCS) function downstream of ROS in abscisic acid (ABA) and methyl jasmonate (MeJA) signalling in guard cells. However, the involvement of RCS in CHT-induced stomatal closure is still unknown. In this study, we used transgenic tobacco (Nicotiana tabacum) plants overexpressing Arabidopsis thaliana 2-alkenal reductase (AER-OE tobacco) and Arabidopsis wild-type (WT) plants to investigate whether RCS is involved in CHT-induced stomatal closure. Chitosan-induced stomatal closure was inhibited in the tobacco AER-OE plants. In the WT tobacco and Arabidopsis plants, CHT-induced stomatal closure was inhibited by RCS scavengers, carnosine and pyridoxamine. Chitosan significantly increased RCS production in the WT tobacco and Arabidopsis, but in the tobacco AER-OE plants, chitosan did not increase significantly RCS accumulation. Moreover, neither the application of RCS scavengers to both WT plants nor scavenging RCS by AER-OE affected the CHT-induced ROS accumulation. However, treatment with a peroxidase inhibitor, SHAM, significantly inhibited CHT-induced RCS accumulation in WT tobacco and Arabidopsis plants. Taken together, these results suggest that RCS acts downstream of ROS production in CHT signalling in guard cells of A. thaliana and N. tabacum.

DOI： 10.1111/ppl.70094

Polyphenol oxidase mediated (-)-epigallocatechin gallate stabilized protein in body wall of Apostichopus japonicus: Characteristics and structure. Reviewed International journal

Yicheng Guo, Yu Ming, Xiufang Dong, Yoshimasa Nakamura, Xiuping Dong, Hang Qi

Food chemistry 470 142710 - 142710 2024.12

Language：English Publishing type：Research paper (scientific journal)

Heat treatment is the most common processing method in Apostichopus japonicus (A. japonicus) processing. However, improper heat treatment can lead to the degradation of protein. In an effort to mitigate this occurrence, we looked into how the protein in the body wall of A. japonicus (AJBWP) was affected by polyphenol oxidase (PPO)-mediated (-)-epigallocatechin gallate (EGCG). The results showed that polyphenol oxidase-mediated EGCG induced protein aggregation. Meanwhile, the antioxidant and thermal stability of the protein were enhanced, and the digestive properties of the protein were inhibited. Protein structure studies have shown that polyphenol oxidase mediated EGCG changes the secondary and tertiary structure of proteins and can maintain the microstructure of proteins after heat treatment. In conclusion, polyphenol oxidase-mediated EGCG was a way to improve the thermal stability of body wall proteins and alleviate the thermal degradation of proteins in A. japonicus.

DOI： 10.1016/j.foodchem.2024.142710

Advanced characterization of fish skin gelatin-proanthocyanidins covalent and non-covalent composite emulsions for benzyl isothiocyanate delivery. Reviewed International journal

Yuhang Shen, Songyi Lin, Liang Song, Peng Sun, Yoshimasa Nakamura, Yue Tang

International journal of biological macromolecules 139071 - 139071 2024.12

Language：English Publishing type：Research paper (scientific journal)

This research endeavored to engineer robust delivery matrices for bioactives, specifically benzyl isothiocyanate (BITC), by harnessing the synergistic covalent and non-covalent interactions between fish skin gelatin (FSG) and proanthocyanidins (PC) to synthesize novel composite emulsions. The objective was to delineate the influence of these molecular interactions on the emulsion's structural integrity and stability, which are pivotal for the efficacious encapsulation and controlled release of BITC. Employing a suite of analytical techniques, including Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy, and contact angle measurements, the study delineated the predominant molecular forces at play within the FSG-PC complex, identifying electrostatic and hydrophobic interactions as the cornerstones of this interaction. An assessment of the emulsions' physicochemical properties, encompassing chromaticity, antioxidant efficacy, microstructural attributes, particle dimensions, zeta potential, and BITC retention, was undertaken to discern the optimal encapsulation strategy. The data unequivocally indicated that emulsions enriched with 0.06 wt% PC, in non-covalent synergy with FSG, afforded the most pronounced stability and retention of BITC. This work paves the way for future studies and the translational application of FSG-PC composite emulsions in the realm of bioactive substance delivery, offering a promising avenue for innovation in pharmaceutical and nutraceutical formulations.

DOI： 10.1016/j.ijbiomac.2024.139071

GUARD CELL HYDROGEN PEROXIDE-RESISTANT1 functions upstream of reactive carbonyl species production in Arabidopsis guard-cell abscisic acid signaling. Reviewed International journal

Oumayma Shaiek, Huifei Yin, Nodoka Uesako, Md Moshiul Islam, Mohammad Saidur Rhaman, Toshiyuki Nakamura, Yoshimasa Nakamura, Shintaro Munemasa, Jun'ichi Mano, Yoshiyuki Murata

Bioscience, biotechnology, and biochemistry 2024.9

Language：English Publishing type：Research paper (scientific journal)

GUARD CELL HYDROGEN PEROXIDE-RESISTANT1 (GHR1), a leucine-rich repeat receptor-like kinase, is involved in abscisic acid (ABA)-induced stomatal closure. We investigated the role of GHR1 in reactive oxygen species (ROS) signaling for ABA-induced stomatal closure. Abscisic acid induced ROS production in wild type (WT) and the ghr1 of Arabidopsis thaliana. Hydrogen peroxide induced stomatal closure, accompanying the generation of acrolein in guard cells. The reactive carbonyl species (RCS) scavengers inhibited the ABA- and H2O2-induced stomatal closure in WT. In the ghr1, H2O2 failed to induce acrolein production and stomatal closure while RCS induced stomatal closure. Thus, GHR1 functions downstream of ROS and is required for the generation of RCS in guard-cell ABA signaling. In the ghr1, Ca2+ induced stomatal closure but RCS did not activate ICa channels. The GHR1 may be also involved in a Ca2+-independent pathway for ABA-induced stomatal closure.

DOI： 10.1093/bbb/zbae135

Mechanism of inhibition of melanoma by fucoxanthin simulated in vitro digestion products in cell models constructed using human malignant melanoma cells (A375) and keratinocytes (HaCaT). Reviewed International journal

Yujing Lu, Yida Wang, Tian Yao, Xiufang Dong, Yu Liu, Yoshimasa Nakamura, Hang Qi

Food chemistry 462 141003 - 141003 2024.8

Language：English Publishing type：Research paper (scientific journal)

Recently, the increasing incidence of malignant melanoma has become a major public health concern owing to its poor prognosis and impact on quality of life. Consuming foods with potent antitumor compounds can help prevent melanoma and maintain skin health. Fucoxanthin (FX), a naturally occurring carotenoid found in brown algae, possesses antitumor properties. However, its bioavailability, safety risks, and in vivo effects and mechanisms against melanoma remain unclear. This research focused on evaluating the safety and prospective antimelanoma impact of simulated gastrointestinal digestion products (FX-ID) on HaCaT and A375 cells.The results indicate that FX-ID exerts negative effects on mitochondria in A375 cells, increases Bax expression, releases Cytochrome C, and activates cleaved caspase-3, ultimately promoting apoptosis. Additionally, FX-ID influences the mitogen-activated protein kinase (MAPK) pathway by enhancing cyclooxygenase-2 (COX-2) and nuclear factor kappa B (NF-κB) levels, consequently facilitating apoptosis and inflammation without significantly impacting HaCaT cells. These findings provide insight into inhibitory mechanism of FX-ID against melanoma, guiding the development of functional foods for prevention.

DOI： 10.1016/j.foodchem.2024.141003

Whey protein and flaxseed gum co-encapsulated fucoxanthin promoted tumor cells apoptosis based on MAPK-PI3K/Akt regulation on Huh-7 cell xenografted nude mice. Reviewed International journal

Chunyan Wang, Xu Huang, Kailing Sun, Xiang Li, Dingding Feng, Yoshimasa Nakamura, Hang Qi

International journal of biological macromolecules 134838 - 134838 2024.8

Language：English Publishing type：Research paper (scientific journal)

Fucoxanthin (FX), a non-provitamin-A carotenoid, is a well-known major xanthophyll contained in edible brown algae. The nanoencapsulation of FX was motivated due to its multiple activities. Here, nano-encapsulated-FX (nano-FX) was prepared according to our early method by using whey protein and flaxseed gum as the biomacromolecule carrier material, then in vivo antitumor effect and mechanism of nano-FX on xenograft mice were investigated. Thirty 4-week-old male BALB/c nude mice were fed adaptively for 7 days to establish xenograft tumor model with Huh-7 cells. The tumor-bearing mice consumed nano-FX (50, 25, and 12.5 mg kg-1) and doxorubicin hydrochloride (DOX, 1 mg kg-1) or did not consume (Control) for 21 days, n = 6. The tumor inhibition rates of nano-FX were as high as 54.67 ± 1.04 %. Nano-FX intervention promoted apoptosis and induced hyperchromatic pyknosis and focal necrosis in tumor tissue by down-regulating the expression of p-JNK, p-ERK, PI3Kp85α, p-AKT, p-p38MAPK, Bcl-2, CyclinD1 and Ki-67, while up-regulating the expression of cleaved caspase-3 and Bax. Nano-FX inhibited tumor growth and protected liver function of tumor bearing mice in a dose-dependent manner, up-regulate the level of apoptosis-related proteins, inhibit the MAPK-PI3K/Akt pathways, and promote tumor cell apoptosis.

DOI： 10.1016/j.ijbiomac.2024.134838

The Metabolite of γ-Tocopherol, 2,7,8-Trimethyl-2-(2′-Carboxyethyl)-6-Hydroxychroman, Exerts Intracellular Antioxidant Activity via Up-Regulation of Heme Oxygenase-1 in Hepatocytes Invited Reviewed

Shosuke Aoyama, Tomoka Nishio, Daiki Moriya, Shintaro Munemasa, Yoshiyuki Murata, Yoshimasa Nakamura, Toshiyuki Nakamura

Nutraceuticals 2024.8

Outward-rectifying potassium channels GORK and SKOR function in regulation of root growth under salt stress in Arabidopsis thaliana. Reviewed International journal

Hafsa Jahan Hiya, Yoshitaka Nakashima, Airi Takeuchi, Toshiyuki Nakamura, Yoshimasa Nakamura, Yoshiyuki Murata, Shintaro Munemasa

Journal of plant physiology 302 154322 - 154322 2024.8

Language：English Publishing type：Research paper (scientific journal)

Plants often face high salinity as a significant environmental challenge with roots being the first responders to this stress. Maintaining K+/Na+ ratio within plant cells is crucial for survival, as the intracellular K+ level decreases and the intracellular Na+ level increases under saline conditions. However, knowledge about the molecular regulatory mechanisms of K+ loss in response to salt stress through outward-rectifying K+ channels in plants is largely unknown. In this study, we found that the Arabidopsis double mutant gorkskor, in which the GORK and SKOR genes are disrupted, showed an improved primary root growth under salt stress compared to wild-type (WT) and the gork and skor single-mutant plants. No significant differences in the sensitivity to mannitol stress between the WT and gorkskor mutant were observed. Accumulation of ROS induced by salt stress was reduced in the gorkskor roots. The gorkskor mutant seedlings had significantly higher K+ content, lower Na+ content, and a greater resultant K+/Na+ ratio than the WT under salt stress. Moreover, salt-stress-induced elevation of cytosolic free Ca2+ concentration was reduced in the gorkskor roots. Taken together, these results suggest that Arabidopsis Shaker-type outward-rectifying K+ channels GORK and SKOR may redundantly function in regulation of primary root growth under salt stress and are involved in not only the late-stage response (e.g. K+ leakage) but also the early response including ROS production and [Ca2+]cyt elevation.

DOI： 10.1016/j.jplph.2024.154322

Negative regulation of chitosan-induced stomatal closure by glutathione in Arabidopsis thaliana. Reviewed International journal

Israt Jahan, Shintaro Munemasa, Toshiyuki Nakamura, Yoshimasa Nakamura, Yoshiyuki Murata

Bioscience, biotechnology, and biochemistry 2024.5

Language：English Publishing type：Research paper (scientific journal)

Chitosan (CHT) is a deacylated derivative of chitin and improves growth and yield performance, activates defensive genes, and also induces stomatal closure in plants. Glutathione (GSH) has significant functions in the growth, development, defense systems, signaling, and gene expression. Glutathione negatively regulates abscisic acid (ABA)-, methyl jasmonate (MeJA)-, and salicylic acid (SA)-induced stomatal closure. However, the negative regulation by GSH of CHT-induced stomatal closure is still unknown. Regulation of CHT-induced stomatal closure by GSH in guard cells was investigated using two GSH-deficient mutants, cad2-1 and ch1-1, and a GSH-decreasing chemical, 1-chloro-2,4-dinitrobenzene (CDNB). The cad2-1 and ch1-1 mutations and CDNB treatment enhanced CHT-induced stomatal closure. Treatment with glutathione monoethyl ester (GSHmee) restored the GSH level in the guard cells of cad2-1 and ch1-1 and complemented the stomatal phenotype of the mutants. These results indicate that GSH negatively regulates CHT-induced stomatal closure in A. thaliana.

DOI： 10.1093/bbb/zbae065

Unlocking stability and efficiency in benzyl isothiocyanate-loaded emulsions: Unveiling synergistic interactions of fish skin gelatin and pectin Reviewed

Liu Wenwen, Lin Songyi, Song Liang, Wang Siyu, Nakamura Yoshimasa, Tang Yue

Food Bioscience 58 103788 - 103788 2024.4

Polyphenol oxidase mediates (-)-epigallocatechin gallate to inhibit endogenous cathepsin activity in Apostichopus japonicus. Reviewed International journal

Yicheng Guo, Yu Ming, Kailing Sun, Xiufang Dong, Yoshimasa Nakamura, Xiuping Dong, Hang Qi

Food chemistry 449 139166 - 139166 2024.3

Language：English Publishing type：Research paper (scientific journal)

Apostichopus japonicus (A. japonicus) has rich nutritional value and is an important economic crop. Due to its rich endogenous enzyme system, fresh A. japonicus is prone to autolysis during market circulation and storage, resulting in economic losses. In order to alleviate this phenomenon, we investigated the effect of polyphenol oxidase (PPO) mediated (-)-epigallocatechin gallate (EGCG) on the activity and structure of endogenous cathepsin series protein (CEP) from A. japonicus. Research on cathepsin activity showed that PPO mediated EGCG could significantly reduce enzyme activity, resulting in a decrease in enzymatic reaction rate. SDS-PAGE and scanning electron microscopy results showed that PPO mediates EGCG could induce CEP aggregation to form protein aggregates. Various spectral results indicated that EGCG caused changes in the structure of CEP. Meanwhile, the conjugates formed by PPO mediated EGCG had lower thermal stability. In conclusion, PPO mediated EGCG was an effective method to inhibit the endogenous enzyme activity.

DOI： 10.1016/j.foodchem.2024.139166

Enhancing effect of the coexisting alpha-tocopherol on quercetin absorption and metabolism. Reviewed International journal

Rikito Mitsuzane, Reiko Okubo, Miyu Nishikawa, Shinichi Ikushiro, Shintaro Munemasa, Yoshiyuki Murata, Yoshimasa Nakamura, Toshiyuki Nakamura

Free radical research 58 ( 2 ) 1 - 16 2024.2

Language：English Publishing type：Research paper (scientific journal)

The aim of this study is to investigate the modulating effect of coexisting food components on the absorption and metabolism of quercetin and blood plasma antioxidant potentials. The combination of quercetin with α-tocopherol (αT), cellulose, or a commercially-available vegetable beverage containing αT and dietary fiber was orally administered to mice. Compared to the single administration of quercetin aglycone, the co-administration of αT with quercetin significantly increased the plasma quercetin concentration at 0.5 h, whereas the combination of quercetin and cellulose decreased it. Interestingly, the administration of quercetin mixed with the vegetable beverage showed no significant change of the quercetin concentration in the mice plasma. The treatment of the cells with the blood plasma after the co-administration of αT with quercetin significantly upregulated the gene expression of the antioxidant enzyme (heme oxygenase-1), whereas the quercetin and cellulose combination did not. In the plasma of the quercetin-administered mice, eight types of quercetin metabolites were detected and their quantities were affected by the combination with αT. The potentials of the heme oxygenase-1 gene expression by these metabolites were very limited, although several metabolites showed radical scavenging activities comparable to aglycone in the in vitro assays. These results suggested that the combination of αT potentiates the quercetin absorption and metabolism and thus the plasma antioxidant potentials, at least in part, by the quantitative changes in the quercetin metabolites.

DOI： 10.1080/10715762.2024.2317206

Aromatic oil from lavender as an atopic dermatitis suppressant Reviewed International journal

Haruna Sato, Kosuke Kato, Mayuko Koreishi, Yoshimasa Nakamura, Yoshio Tsujino, Ayano Satoh

PLOS ONE 19 ( 1 ) e0296408 2024.1

Language：English Publishing type：Research paper (scientific journal)

In atopic dermatitis (AD), nerves are abnormally stretched near the surface of the skin, making it sensitive to itching. Expression of neurotrophic factor Artemin (ARTN) involved in such nerve stretching is induced by the xenobiotic response (XRE) to air pollutants and UV radiation products. Therefore, AD can be monitored by the XRE response. Previously, we established a human keratinocyte cell line stably expressing a NanoLuc reporter gene downstream of XRE. We found that 6-formylindolo[3,2-b]carbazole (FICZ), a tryptophan metabolite and known inducer of the XRE, increased reporter and Artemin mRNA expression, indicating that FICZ-treated cells could be a model for AD. Lavender essential oil has been used in folk medicine to treat AD, but the scientific basis for its use is unclear. In the present study, we investigated the efficacy of lavender essential oil and its major components, linalyl acetate and linalool, to suppress AD and sensitize skin using the established AD model cell line, and keratinocyte and dendritic cell activation assays. Our results indicated that lavender essential oil from L. angustifolia and linalyl acetate exerted a strong AD inhibitory effect and almost no skin sensitization. Our model is useful in that it can circumvent the practice of using animal studies to evaluate AD medicines.

DOI： 10.1371/journal.pone.0296408

Detection of Simulated In Vitro Digestion Products of Fucoxanthin and Their Photodamage Alleviation Effect in Retinal Müller Cells Induced by Ultraviolet B Irradiation: A Proteomics Analysis. Reviewed International journal

Yixin Shi, Yingzhen Wang, Haotian Zou, Baomin Zhao, Taihai Zhu, Yoshimasa Nakamura, Hang Qi

Journal of agricultural and food chemistry 71 ( 40 ) 14626 - 14637 2023.10

Language：English Publishing type：Research paper (scientific journal)

Our previous study reported that the marine dietary bioactive compound fucoxanthin (FX) has the potential to reduce the level of oxidation in retinal Müller cells (RMCs) induced by ultraviolet B (UVB) irradiation. However, the gastrointestinal environment can inhibit the bioavailability and absorption of FX in the cell systems. In the current study, FX was initially digested in a simulated in vitro gastrointestinal fluid. Nine main digestive products were identified, and the photoprotective activities of FX simulated in vitro gastrointestinal digestion products (FX-ID) were assessed in the same RMC model. FX-ID significantly reduced intracellular ROS and alleviated apoptosis. Western blot assays showed that FX-ID inhibited phosphorylated proteins in the MAPK and NF-κB signaling pathways. Our proteomics analysis revealed that the differentially expressed proteins were linked to biological networks associated with antioxidation and metabolic processes. The data may provide insight into the photoprotective mechanisms of FX-ID and promote the development of various functional foods to prevent retinal disorders.

DOI： 10.1021/acs.jafc.3c03853

The effect of exogenous dihydroxyacetone and methylglyoxal on growth, anthocyanin accumulation, and the glyoxalase system in Arabidopsis. Reviewed International journal

Maoxiang Zhao, Toshiyuki Nakamura, Yoshimasa Nakamura, Shintaro Munemasa, Izumi C Mori, Yoshiyuki Murata

Bioscience, biotechnology, and biochemistry 87 ( 11 ) 1323 - 1331 2023.8

Language：English Publishing type：Research paper (scientific journal)

Dihydroxyacetone (DHA) occurs in wide-ranging organisms including plants and can undergo spontaneous conversion to methylglyoxal (MG). While the toxicity of MG to plants is well-known, the toxicity of DHA to plants remains to be elucidated. We investigated the effects of DHA and MG on Arabidopsis. Exogenous DHA at up to 10 m m did not affect the radicle emergence, the expansion of green cotyledons, the seedling growth, or the activity of glyoxalase II while DHA at 10 m m inhibited the root elongation and increased the activity of glyoxalase I. Exogenous MG at 1.0 m m inhibited these physiological responses and increased both activities. DHA at 10 m m increased the MG content in the roots. These results indicate that DHA is not so toxic as MG in Arabidopsis seeds and seedlings and suggest that the toxic effect of DHA at high concentrations is attributed to MG accumulation by the conversion to MG.

DOI： 10.1093/bbb/zbad109

Characterisation of zinc‐chelating peptides derived from scallop (Patinopecten yessoensis) mantle and their intestinal transport in everted rat sacs Reviewed

Xiaoyang Liu, Jiatong Sun, Yue Li, Xuening Yu, Fawen Yin, Deyang Li, Pengfei Jiang, Yoshimasa Nakamura, Dayong Zhou

International Journal of Food Science & Technology 2023.5

ALDEHYDE DEHYDROGENASES AS POTENTIAL TARGETS FOR ETHANOL-RELATED DISEASES

XU Yuhang, NAKAMURA Toshiyuki, NAKAMURA Yoshimasa

Journal of Environmental Science for Sustainable Society 12 ( Supplement ) MR03_p9 - MR03_p12 2023.4

Authorship：Last author,　Corresponding author Language：English Publisher：Graduate School of Environmental and Life Science, Okayama University

Since acetaldehyde is a toxic metabolite of ethanol, its accumulation causes several acute and chronic diseases related to the excessive intake of alcoholic beverages. Aldehyde dehydrogenases (ALDHs) play an important role in the metabolism of not only exogenous aldehydes, but also endogenous ones including acetaldehyde. Among the ALDH family, ALDH2 mainly contributes to acetaldehyde elimination. This paper reviews the function of ALDH2 as well as auxiliary ALDHs in the ethanol metabolism. This paper also summarizes the regulation of the total ALDH activity by certain food chemicals, providing implication for their therapeutic potential against alcohol-related diseases.

DOI： 10.3107/jesss.12.mr03

Characterization of oyster water-soluble protein-EGCG conjugate and its antioxidant effects on linolic acid in emulsion system Reviewed

Yue Li, Xiaoyang Liu, Fawen Yin, Deyang Li, Pengfei Jiang, Liang Song, Yoshimasa Nakamura, Dayong Zhou

Food Bioscience 51 102215 - 102215 2023.2

Polyphenol extracts from Ascophyllum nodosum protected sea cucumber (Apostichopus japonicas) body wall against thermal degradation during tenderization Reviewed International journal

Yu Ming, Yingzhen Wang, Yuqianqian Xie, Xiufang Dong, Yoshimasa Nakamura, Xing Chen, Hang Qi

Food Research International 164 112419 - 112419 2023.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier BV

To retard the protein degradation during sea cucumber processing, polyphenol extracts from Ascophyllum nodosum (PhE) was used as a potential antioxidant to maintain the structural integrity of sea cucumber body wall. Accordingly, the protection effects of PhE (0, 0.5, 1.0 and 1.5 mg PhE/g SFBW) against thermal degradation of the solid fragments of body wall (SFBW) have been investigated in order to evaluate their impact on the oxidation level and structural changes. Electronic Spin Resonance results showed that PhE could significantly inhibit the occurrence of oxidation by scavenging the free radicals. The effect of PhE on chemical analysis of soluble matters in SFBW was characterized by SDS-PAGE and HPLC. Compared with thermally treated SFBW, samples with PhE presented a decrease in protein dissolution. Thermal treatment resulted in the disintegration of collagen fibrils and fibril bundles in SFBW samples, while the density of collagen fibrils was increased, and the porosity decreased in samples with PhE. The results of FTIR and intrinsic tryptophan fluorescence confirmed that the structures of SFBW were modified by PhE. Besides, the denaturing temperature and decomposition temperature were both improved with the addition of PhE. These results suggested that PhE appeared to have a positive effect on lowering oxidation and improving thermostability and structural stability of SFBW, which could provide a theoretical basis for protecting sea cucumber body wall against degradation during thermal tenderization.

DOI： 10.1016/j.foodres.2022.112419

第65回大会特別講演ポリフェノールの機能性の分子メカニズム : ポリフェノールはどのようにして機能性を発揮するのか—Molecular mechanisms for polyphenol functionality : How do polyphenols exert their functionality? Invited Reviewed

中村宜督

日本食生活学会誌 = Journal for the integrated study of dietary habits / 日本食生活学会編 33 ( 4 ) 165 - 169 2023

Construction of benzyl isothiocyanate-loaded fish skin gelatin-luteolin compound emulsion delivery system, and its digestion and absorption characteristics. Reviewed International journal

Zhiyu Liu, Songyi Lin, Wenwen Liu, Yoshimasa Nakamura, Yue Tang

Journal of the science of food and agriculture 103 ( 4 ) 1864 - 1873 2022.12

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Fish skin gelatin (FSG) and luteolin (LUT) were used as composite emulsifiers, and benzyl isothiocyanate (BITC) was used as a model of nutrient delivery to construct a stable emulsion. The storage stability of the FSG-LUT emulsion and its effect on BITC release were investigated both in vitro and ex vivo. RESULTS: LUT can quench FSG fluorophores statically and form a stable complex through hydrogen bonding and hydrophobic interactions. The FSG-LUT emulsion storage stability and embedding rate were higher than those of the FSG emulsion. The FSG-LUT emulsion microstructure was resistant to oral and gastric digestion, and the BITC retention rate and bioaccessibility were much higher than those of the FSG emulsion. Lastly, the ex-vivo everted gut sac of rat intestine study demonstrated that BITC showed the highest absorption in the ileum, and the FSG-LUT emulsion absorbed BITC and sustained a controlled release in a specific position. CONCLUSION: LUT could form stable complexes with FSG, which improved the stability and bioavailability of BITC in the FSG-LUT emulsion delivery system, and promoted further intestinal BITC absorption. This article is protected by copyright. All rights reserved.

DOI： 10.1002/jsfa.12411

Phlorotannin Extracts from Ascophyllum nodosum Inhibited Proteases Activities and Structural Changes from Apostichopus japonicus Reviewed

Yu Ming, Yingzhen Wang, Yuqianqian Xie, Chenghang Sun, Xiufang Dong, Yoshimasa Nakamura, Xing Chen, Xiuping Dong, Hang Qi

ACS Food Science & Technology 2 ( 10 ) 1586 - 1596 2022.10

Effects of Domestic Cooking Methods on Physichochemical Properties, Bioactive Compounds and Antioxidant Activities of Vegetables: A Mini-Review Reviewed

Shan Jiang, Meiqi Yu, Pengfei Jiang, Yoshimasa Nakamura, Hang Qi

Food Reviews International 1 - 15 2022.10

Immune State Conversion of the Mesenteric Lymph Node in a Mouse Breast Cancer Model. Reviewed International journal

Tsukasa Shigehiro, Maho Ueno, Mayumi Kijihira, Ryotaro Takahashi, Chiho Umemura, Eman A Taha, Chisaki Kurosaka, Megumi Asayama, Hiroshi Murakami, Ayano Satoh, Yoshimasa Nakamura, Junichiro Futami, Junko Masuda

International journal of molecular sciences 23 ( 19 ) 2022.9

Language：English Publishing type：Research paper (scientific journal)

Secondary lymphoid tissues, such as the spleen and lymph nodes (LNs), contribute to breast cancer development and metastasis in both anti- and pro-tumoral directions. Although secondary lymphoid tissues have been extensively studied, very little is known about the immune conversion in mesenteric LNs (mLNs) during breast cancer development. Here, we demonstrate inflammatory immune conversion of mLNs in a metastatic 4T1 breast cancer model. Splenic T cells were significantly decreased and continuously suppressed IFN-γ production during tumor development, while myeloid-derived suppressor cells (MDSCs) were dramatically enriched. However, T cell numbers in the mLN did not decrease, and the MDSCs only moderately increased. T cells in the mLN exhibited conversion from a pro-inflammatory state with high IFN-γ expression to an anti-inflammatory state with high expression of IL-4 and IL-10 in early- to late-stages of breast cancer development. Interestingly, increased migration of CD103+CD11b+ dendritic cells (DCs) into the mLN, along with increased (1→3)-β-D-glucan levels in serum, was observed even in late-stage breast cancer. This suggests that CD103+CD11b+ DCs could prime cancer-reactive T cells. Together, the data indicate that the mLN is an important lymphoid tissue contributing to breast cancer development.

DOI： 10.3390/ijms231911035

Extracellular malate induces stomatal closure via direct activation of guard-cell anion channel SLAC1 and stimulation of Ca2+ signaling. Reviewed International journal

Yoshiharu Mimata, Shintaro Munemasa, Toshiyuki Nakamura, Yoshimasa Nakamura, Yoshiyuki Murata

The New phytologist 2022.7

Language：English Publishing type：Research paper (scientific journal)

Plants secrete malate from guard cells to apoplast under stress conditions and exogenous malate induces stomatal closure. Malate is considered as an extracellular chemical signal of stomatal closure. However, the molecular mechanism of malate-induced stomatal closure is not fully elucidated. We investigated responses of stomatal aperture, ion channels, and cytosolic Ca2+ to malate. A treatment with malate induced stomatal closure in Arabidopsis thaliana wild-type plants but not in the mutants deficient in the slow (S-type) anion channel gene SLOW ANION CHANNEL-ASSOCIATED 1 (SLAC1). The treatment with malate increased S-type anion currents in guard-cell protoplasts of wild-type plants but not in the slac1 mutant. In addition, extracellular rather than intracellular application of malate increased the S-type currents of constitutively active mutants of SLAC1, which have kinase-independent activities, in a heterologous expression system using Xenopus oocytes. The treatment with malate transiently increased cytosolic Ca2+ concentration in the wild-type Arabidopsis guard cells and the malate-induced stomatal closure was inhibited by the Ca2+ channel blocker and the Ca2+ chelator. These results indicate that extracellular malate directly activates SLAC1 and simultaneously stimulates Ca2+ signaling in guard cells, resulting in steady and solid activation of SLAC1 for stomatal closure.

DOI： 10.1111/nph.18400

Negative regulation of salicylic acid-induced stomatal closure by glutathione in Arabidopsis thaliana. Reviewed International journal

Fahmida Akter, Shintaro Munemasa, Toshiyuki Nakamura, Yoshimasa Nakamura, Yoshiyuki Murata

Bioscience, biotechnology, and biochemistry 2022.7

Language：English Publishing type：Research paper (scientific journal)

Salicylic acid (SA) is a ubiquitous phenolic phytohormone that induces stomatal closure. Glutathione (GSH) negatively regulates stomatal closure induced by other plant hormones such as abscisic acid (ABA) and methyl jasmonate (MeJA). However, the involvement of GSH in SA-induced stomatal closure is still unknown. We investigated the regulation of SA signaling by GSH in guard cells using an Arabidopsis thaliana mutant, cad2-1, which is deficient in the first GSH biosynthesis enzyme, γ-glutamylcysteine synthetase. Application of SA decreased stomatal apertures with decreasing intracellular GSH level in guard cells. Decreasing GSH by the cad2-1 mutation and by a GSH-decreasing chemical, 1-chloro-2,4-dinitrobenzene, enhanced the SA-induced stomatal closure. A treatment with glutathione monoethyl ester restored the GSH level in the cad2-1 guard cells and complemented the stomatal phenotype of the mutant. These results indicate that GSH negatively modulates SA-induced stomatal closure in A. thaliana.

DOI： 10.1093/bbb/zbac116

Malate induces stomatal closure via a receptor-like kinase GHR1- and reactive oxygen species-dependent pathway in Arabidopsis thaliana. Reviewed International journal

Yoshiharu Mimata, Shintaro Munemasa, Fahmida Akter, Israt Jahan, Toshiyuki Nakamura, Yoshimasa Nakamura, Yoshiyuki Murata

Bioscience, biotechnology, and biochemistry 2022.7

Language：English Publishing type：Research paper (scientific journal)

A primary metabolite malate is secreted from guard cells in response to the phytohormone abscisic acid (ABA) and elevated CO2. The secreted malate subsequently facilitates stomatal closure in plants. Here, we investigated the molecular mechanism of malate-induced stomatal closure using inhibitors and ABA signaling component mutants of Arabidopsis thaliana. Malate-induced stomatal closure was impaired by a protein kinase inhibitor, K252a, and also by the disruption of a receptor-like kinase GHR1, which mediates activation of calcium ion (Ca2+) channel by reactive oxygen species (ROS) in guard cells. Malate induced ROS production in guard cells while the malate-induced stomatal closure was impaired by a peroxidase inhibitor, salicylhydroxamic acid, but not by the disruption of NAD(P)H oxidases, RBOHD and RBOHF. The malate-induced stomatal closure was impaired by Ca2+ channel blockers, verapamil and niflumic acid. These results demonstrate that the malate signaling is mediated by GHR1 and ROS in Arabidopsis guard cells.

DOI： 10.1093/bbb/zbac122

Modulating effects of oral administration of Lycii Fructus extracts on UVB-induced skin erythema: A Randomized, placebo-controlled study. Reviewed International journal

Makoto Tsunenaga, Wensi Xu, Takumi Myojin, Toshiyuki Nakamura, Tatsuya Kon, Yoshimasa Nakamura, Osamu Ueda

Biomedical reports 17 ( 1 ) 62 - 62 2022.7

Language：English Publishing type：Research paper (scientific journal)

Severe UV exposure induces skin inflammation, causing erythema. Lycii Fructus (Lycium barbarum and Lycium chinense) is a potential antioxidant agent with a high content of polyphenols, including rutin and chlorogenic acid. This study examined the effects of Lycii Fructus extract (LFE) on UVB-induced skin erythema in humans. Healthy volunteers were randomly assigned to one of two groups and received UVB irradiation at 1.5 minimal erythemal dose (MED) on day 0 at three designated sites on their backs, and the skin color was measured until day 7. After an 8-week treatment with LFE (900 mg/day) or placebo, UVB irradiation (l.5 MED) was applied again at different sites on day 63. Skin color was continuously measured in each group until day 69. LFE tablet administration for 8 weeks significantly inhibited UVB-induced erythema formation and increased the MED by 13%. Erythema formation peaked on the first day after UVB irradiation, but gradually dissipated over the next several days. LFE tended to accelerate erythema disappearance. To determine the polyphenol responsible for the protection against UVB-induced skin damage, the effects of LFE-derived polyphenols and their metabolites on UVB-induced cytotoxicity were examined in vitro. The major intestinal metabolite of rutin and LFE significantly attenuated phototoxicity and in human keratinocyte HaCaT cells. Quercetin enhanced intracellular glutathione levels in HaCaT cells, even though LFE did not increase it. Together, the results showed that LFE inhibited erythema formation and accelerated erythema dissipation, possibly through its direct antioxidative action.

DOI： 10.3892/br.2022.1545

過熱水蒸気処理玄米の食味,物性および抗酸化活性の評価—Evaluation of sensory properties, physical characteristics and antioxidant activity of superheated steam-treated brown rice Reviewed

西本有紀, 矢野愛奈, Wu Hongyan, 西澤正人, 中村俊之, 藤田明子, 中村宜督

美味技術学会誌 = Journal of the Japanese Society of Taste Technology 21 ( 1 ) 20 - 26 2022.7

Antioxidative Effect of Chlorella Pyrenoidosa Protein Hydrolysates and Their Application in Krill Oil-in-Water Emulsions. Reviewed International journal

Yujia Liu, Yuli Qi, Qi Wang, Fawen Yin, Honglei Zhan, Han Wang, Bingnan Liu, Yoshimasa Nakamura, Jihui Wang

Marine drugs 20 ( 6 ) 2022.5

Language：English Publishing type：Research paper (scientific journal)

Chlorella pyrenoidosa is an excellent source of protein, and in this research, we assessed the antioxidant and emulsifying effects of Chlorella protein hydrolysate (CPH) using neutral proteases and alkaline proteases, as well as the properties of CPH-derived krill oil-in-water (O/W) emulsions. The CPHs exhibited the ability to scavenge several kinds of free radicals, including 1,1-diphenyl-2-picrylhydrazyl (DPPH), O2-, hydroxyl, and ABTS. Additionally, the CPHs (5 mg/mL) scavenged approximately 100% of the DPPH and ABTS. The CPHs showed similar emulsifying activities to Tween 20 and excellent foaming activities (max FS 74%), which helped to stabilize the krill oil-in-water emulsion. Less than 10 mg/mL CPHs was able to form fresh krill oil-in-water emulsions; moreover, the CPHs (5 mg/mL) in a krill O/W emulsion were homogenous, opaque, and stable for at least 30 days. Based on their inhibitory effects on the peroxide value (POV) and thiobarbituric acid reactive substances (TRABS), the CPHs were found to be able to inhibit lipid oxidation in both emulsifying systems and krill O/W emulsions. Thus, the CPHs could improve superoxide dismutase (SOD) activities by 5- or 10-fold and decrease the high reactive oxygen species (ROS) level caused by the addition of H2O2 in vitro. In conclusion, health-promoting CPHs could be applied in krill oil-in-water emulsions as both emulsifiers and antioxidants, which could help to improve the oxidative and physical stability of emulsions.

DOI： 10.3390/md20060345

Influence of fish skin gelatin-sodium alginate complex stabilized emulsion on benzyl isothiocyanate stability and digestibility in vitro and in vivo. Reviewed International journal

Xiangyu Zhang, Zhiyu Liu, Ailin Wang, Simin Zhang, Yoshimasa Nakamura, Songyi Lin, Yue Tang

Journal of the science of food and agriculture 2022.4

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: An emulsion delivery system for benzyl isothiocyanate (BITC) was prepared using fish skin gelatin (FSG) and sodium alginate (Alg). The effects of the FSG-Alg complex on the emulsion stability and BITC release pattern from the emulsion were investigated in vitro and in vivo. RESULTS: The storage stability and embedding rate of the 10 g/kg FSG and 2.5 g/kg Alg (FSG-Alg) emulsion were the highest among all samples. The FSG-Alg complex provided BITC a better protection during in vitro digestion. The microstructure of the FSG-Alg emulsions was more stable during in vitro digestion, and the bioaccessibility and retention rate of BITC were much higher compared to those of the FSG emulsion. The results of the ex-vivo everted gut sac of rat intestine study showed that the FSG-Alg emulsion significantly increased the BITC absorption rate in the duodenum. CONCLUSION: The FSG-Alg emulsion delivery system is a highly stable system for the delivery of BITC that improves the bioaccessibility of BITC and promotes its absorption in the duodenum. This article is protected by copyright. All rights reserved.

DOI： 10.1002/jsfa.11915

RING FISSION CATABOLITES OF QUERCETIN GLYCOSIDES

LI Kexin, NAKAMURA Toshiyuki, NAKAMURA Yoshimasa

Journal of Environmental Science for Sustainable Society 11 ( Supplement ) MR02_p5 - MR02_p8 2022.4

Characterization of a synthetic zinc-chelating peptide from sea cucumber (Stichopus japonicus) and its gastrointestinal digestion and absorption in vitro. Reviewed International journal

Zixu Wang, Jiatong Sun, Xiaoyu Ma, Xiaoyang Liu, Fawen Yin, Deyang Li, Yoshimasa Nakamura, Chenxu Yu, Dayong Zhou

Journal of the science of food and agriculture 2022.2

Language：English Publishing type：Research paper (scientific journal)

BACKGROUND: Zinc absorption in intestinal system could be strongly affected by the gastrointestinal digestion and absorption of zinc-chelating peptides serving as zinc carriers. In this study, a novel zinc-chelating sea cucumber synthetic peptide (SCSP) was synthesized to estimate its gastrointestinal digestion and promotive effect of zinc absorption in vitro. RESULTS: Analysis of isothermal titration calorimetry suggested that the binding of SCSP and zinc (N ≈ 1) was exothermic, with relatively weak binding affinity (K = 1.0х10-3 mol L-1 ). The formation of SCSP-Zn complexes brought morphological changes to the peptides confirmed by scanning electron microscopy (SEM), which also indicated 6.88% of the existence of zinc element. In addition, the SCSP-Zn complexes remained stable under simulated human gastrointestinal digestion. In vitro study, the SCSP-Zn complex could successfully transport through the intestinal membrane in the model of everted rat gut sacs (nearly 7.5 μM cm-2 ) as well as Caco-2 cells where the zinc transport reached 0.0014 mg mL-1 carried by SCSP. Fluorescence staining experiments revealed free zinc accumulation inside the tissues and cells treated with the SCSP-Zn. CONCLUSIONS: The chelation SCSP-Zn had the promotion ability of zinc absorption in vitro and ex vivo experiments, which suggested a theoretical basis for the design and production of effective zinc chelating peptides as zinc carriers to improve zinc bioavailability. This article is protected by copyright. All rights reserved.

DOI： 10.1002/jsfa.11811

Gastrointestinal digestion and absorption characterization in vitro of zinc-chelating hydrolysate from scallop adductor (Patinopecten yessoensis). Reviewed International journal

Jiatong Sun, Xiaoyang Liu, Zixu Wang, Fawen Yin, Huilin Liu, Yoshimasa Nakamura, Chenxu Yu, Dayong Zhou

Journal of the science of food and agriculture 2021.11

Language：English Publishing type：Research paper (scientific journal)

BACKGROUD: Zinc is an essential catalytic element in human health system but its absorption in intestinal system could be strongly affected by the gastrointestinal digestion. In this study, the food-derived potential zinc carrier, scallop adductor hydrolysates (SAHs), was produced and characterized. RESULTS: During the temporary storage in 4°C, the SAH decreased in zinc-chelating capacity in aqueous phase whereas the SAH-Zn complex exhibited high stability. Moreover, the secondary structure of SAH had no significant alteration. Zinc morphologically altered the surface structures of SAH, which was involving in carboxyl group of SAH. Results of in vitro gastrointestinal (GI) digestion suggested that the SAH-Zn maintained good stability in GI system and only proportion of high molecular weight cleaved. In addition, SAH could successfully carry and transport zinc while the fluorescence staining revealed free zinc accumulation inside the tissue. Finally, 3 representative absorbed peptides (around 600 Da) were identified and synthesized. Three synthetic peptides exhibit higher zinc-chelating capacity than SAH and could also successfully transported through the intestine. CONCLUSION: This study provided a theoretical basis for the investigation of digestion and absorption of marine animal-derived peptides as zinc carriers. This article is protected by copyright. All rights reserved.

DOI： 10.1002/jsfa.11673

Neither glutamate nor alanine but arginine sensitizes BY-2 cells to arsenate. Reviewed International journal

Nur-E-Nazmun Nahar, Md Yeasin Prodhan, Yoshiharu Mimata, Anna Yonezawa, Toshiyuki Nakamura, Yoshimasa Nakamura, Shintaro Munemasa, Yoshiyuki Murata

Bioscience, biotechnology, and biochemistry 2021.10

Language：English Publishing type：Research paper (scientific journal)

Arsenic is toxic for plants. Our previous results showed that the application of proline enhanced the sensitivity of tobacco BY-2 cells to arsenate. In order to clarify the enhancement mechanism, we investigated the effects of other amino acids on the arsenate-stressed BY-2 cells. Glutamate at up to 10 mM did not affect the cell growth in the absence or presence of arsenate. Arginine at up to 10 mM did not affect the growth in the absence of arsenate but arginine at 10 mM enhanced the inhibition of the cell growth by arsenate. Alanine at up to 10 mM did not affect the cell growth under non-stressed condition but alanine at 10 mM significantly improved the cell growth under arsenate stress. These results suggest that alanine mitigates arsenate stress in BY-2 cells and that arginine like proline enhances the sensitivity of BY-2 cells to arsenate.

DOI： 10.1093/bbb/zbab191

White rice ethanol extract is qualitatively, but not quantitatively, equivalent to that of brown rice as an antioxidant source. Reviewed International journal

Hongyan Wu, Toshiyuki Nakamura, Yingnan Guo, Miho Hirooka, Gongliang Zhang, Shintaro Munemasa, Yoshiyuki Murata, Akiko Fujita, Yoshimasa Nakamura

Bioscience, biotechnology, and biochemistry 85 ( 10 ) 2161 - 2168 2021.9

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

The purpose of this study is to compare the potentials to exhibit biologically active antioxidant actions between white rice (WR) and brown rice (BR) in in vitro assays and a cellular model. The Trolox equivalent (TE) per 1 mg ethanol extract of WR for the 1,1-diphenyl-2-picrylhydrazyl assay was slightly higher than that of BR, whereas the TE per 1 g whole WR was much lower than that for BR. This tendency was very comparable to those for the oxygen radical absorbance capacity and total polyphenol content. Both of the ethanol extracts also similarly suppressed the hydrogen peroxide-induced cytotoxicity and enhanced the gene expression of drug-metabolizing enzymes. Based on the α-tocopherol quantity, its contribution to the cytoprotective effect of the rice extracts is very limited. Taken together, the ethanol extract of WR might be a qualitatively, but not quantitatively, equivalent source of antioxidative phytochemicals to that of BR.

DOI： 10.1093/bbb/zbab133

Cadmium uptake via apoplastic bypass flow in Oryza sativa. Reviewed

Izumi C Mori, Carlos Raul Arias-Barreiro, Lia Ooi, Nam-Hee Lee, Muhammad Abdus Sobahan, Yoshimasa Nakamura, Yoshihiko Hirai, Yoshiyuki Murata

Journal of plant research 134 ( 5 ) 1139 - 1148 2021.9

Language：English Publishing type：Research paper (scientific journal)

It is known that rice roots take up cadmium (Cd) via the symplastic route mediated by membrane-bound mineral transporters. Here we provide evidence that apoplastic bypass flow is another Cd uptake route in rice. High concentrations of Cd rendered apoplastic bypass flow rate increased in rice seedlings. These concentrations of Cd compromised membrane integrity in the root meristem and transition zone. Polyethleneglycol and proline inhibited the Cd-induced apoplastic bypass flow and Cd transfer to the shoots. Loss-of-function mutant of the Cd uptake transporter, nramp5, showed Cd transport to the shoot comparable to the wild type. At a low Cd concentration, increased apoplastic bypass flow rate by NaCl stress resulted in an elevation of Cd transport to shoots both in the wildtype and nramp5. These observations indicate that apoplastic bypass flow in roots carries Cd transport leading to xylem loading of Cd in addition to the symplastic pathway mediated by mineral transporters under stressed conditions.

DOI： 10.1007/s10265-021-01319-y

Modulation of frequency and height of cytosolic calcium spikes by plasma membrane anion channels in guard cells. Reviewed International journal

Md Tahjib-Ul-Arif, Shintaro Munemasa, Toshiyuki Nakamura, Yoshimasa Nakamura, Yoshiyuki Murata

Bioscience, biotechnology, and biochemistry 85 ( 9 ) 2003 - 2010 2021.8

Language：English Publishing type：Research paper (scientific journal)

Cytosolic calcium ([Ca2+]cyt) elevation activates plasma membrane anion channels in guard cells, which is required for stomatal closure. However, involvement of the anion channels in the [Ca2+]cyt elevation remains unclear. We investigated the involvement using Arabidopsis thaliana anion channel mutants, slac1-4 slah3-3 and slac1-4 almt12-1. Extracellular calcium induced stomatal closure in the wild-type plants but not in the anion channel mutant plants whereas extracellular calcium induced [Ca2+]cyt elevation both in the wild-type guard cells and in the mutant guard cells. The peak height and the number of the [Ca2+]cyt spike were lower and larger in the slac1-4 slah3-3 than in the wild type and the height and the number in the slac1-4 almt12-1 were much lower and much larger than in the wild type. These results suggest that the anion channels are involved in the regulation of [Ca2+]cyt elevation in guard cells.

DOI： 10.1093/bbb/zbab118

Luteolin suppresses 5-hydroxytryptamine elevation in stimulated RBL-2H3 cells and experimental colitis mice. Reviewed

Naoko Suga, Akira Murakami, Hideyuki Arimitsu, Toshiyuki Nakamura, Yoshimasa Nakamura, Yoji Kato

Journal of clinical biochemistry and nutrition 69 ( 1 ) 20 - 27 2021.7

Language：English Publishing type：Research paper (scientific journal)

Increased 5-hydroxytryptamine may be associated with the development and progression of inflammatory bowel disease. In this study, we examined the suppressive effect of flavonoids on the increased intra- and extracellular 5-hydroxytryptamine levels in rat mast RBL-2H3 cells, known to produce 5-hydroxytryptamine by the phorbol 12-myristate 13-acetate stimulation. Among the flavonoids examined, luteolin and quercetin significantly reduced the cellular 5-hydroxytryptamine concentration. Gene and protein expression analyses revealed that luteolin significantly suppressed cellular tryptophan hydroxylase 1 expression induced by phorbol 12-myristate 13-acetate stimulation. Mitogen-activated protein kinase/extracellular signal-regulated kinase signaling was also suppressed by luteolin, suggesting that this pathway is one of targets of 5-hydroxytryptamine modulation by luteolin. An in vivo experimental colitis model was prepared by administering 2.5% dextran sodium sulfate in drinking water to C57BL/6 mice for seven days. The ingestion of 0.1% dietary luteolin suppressed the increasing 5-hydroxytryptamine in the colorectal mucosa. In conclusion, luteolin possesses a suppressive effect on extensive 5-hydroxytryptamine formation in both experimental RBL-2H3 cells and colitis models.

DOI： 10.3164/jcbn.20-192

A multidrug resistance-associated protein inhibitor is a potential enhancer of the benzyl isothiocyanate-induced apoptosis induction in human colorectal cancer cells. Reviewed International journal

Qifu Yang, Toshiyuki Nakamura, Masayuki Seto, Miku Miyagawa, Wensi Xu, Beiwei Zhu, Shintaro Munemasa, Yoshiyuki Murata, Yoshimasa Nakamura

Journal of biochemical and molecular toxicology 35 ( 7 ) e22791 2021.7

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

The increasing drug efflux through the ATP-binding cassette (ABC) transporters is the most plausible mechanism that mediates resistance to the anticancer phytochemicals, such as benzyl isothiocyanate (BITC), as well as chemotherapy drugs. To identify a potential component to overcome this resistance by combinatory utilization, we focused on multidrug resistance-associated proteins (MRPs) pumping various drug metabolites with glutathione as well as the organic anions. The pharmacological treatment of an MRP inhibitor, MK571, significantly potentiated the BITC-induced antiproliferation, coincided with the enhanced accumulation of BITC and glutathione in human colorectal cancer HCT-116 cells. MK571 also enhanced the apoptosis induction as well as activation of the mitogen-activated protein kinases and caspase-3, whereas it did not affect their basal levels. These results suggested that, since MRPs might play a pivotal role in the BITC efflux, MK571 potentiates the BITC-induced antiproliferation in human colorectal cancer cells through inhibition of the glutathione-dependent BITC efflux.

DOI： 10.1002/jbt.22791

Functional Evaluation of the Ethanol Extracts from Rosmarinus officinalis L. (Rosemary) Reviewed

Yamada Naofumi, Yamasaki Tsutomu, Yamawaki Kana, Nakagiri Minami, Ito Hideyuki, Nakamura Yoshimasa, Nakanishi Tohru

Journal of Hard Tissue Biology 30 ( 3 ) 291 - 296 2021

Language：English Publisher：THE SOCIETY FOR HARD TISSUE REGENERATIVE BIOLOGY

<p>Rosemary is used as an herb in cooking and aromatic oils, and has long been used as a medicinal herb because of its functional components. According to folklore, monks recommended a remedy of rosemary in alcohol ("Hungarian water") to a Hungarian queen suffering from limb numbness, resulting in instant recovery and rejuvenation. This is why the queen married a 20-year-old king of Holland while in her seventies. In order to clarify the "rejuvenation" mechanisms of traditional Hungarian water, we examined the anti-oxidant activity, anti-glycation activity, inhibition of melanin production and suppression of tumor growth of ethanol extracts of rosemary in this study. It was found that the ethanol extract had high anti-oxidant activity, high anti-glycation activity, high inhibition of melanin production and high suppression of tumor cell growth.</p>

DOI： 10.2485/jhtb.30.291

PREDOMINANT RICE PHYTOCHEMICALS AND THEIR DISEASE-PREVENTIVE EFFECTS

WU Hongyan, NAKAMURA Toshiyuki, NAKAMURA Yoshimasa

Journal of Environmental Science for Sustainable Society (Web) 10 ( Supplement ) 1 - 4 2021

Stomatal response to isothiocyanates in Arabidopsis thaliana. Reviewed International journal

Sonya Afrin, Eiji Okuma, Md Tahjib-Ul-Arif, Md Sarwar Jahan, Toshiyuki Nakamura, Yoshimasa Nakamura, Shintaro Munemasa, Yoshiyuki Murata

Journal of experimental botany 71 ( 22 ) 6921 - 6931 2020.12

Language：English Publishing type：Research paper (scientific journal)

Allyl isothiocyanate (AITC) induces stomatal closure accompanied by reactive oxygen species (ROS) production and glutathione (GSH) depletion in Arabidopsis thaliana. In this study, stomatal responses to three other isothiocyanates (ITCs), benzyl isothiocyanate (BITC), sulforaphane (SFN), and phenethyl isothiocyanate (PEITC), were investigated in A. thaliana. All these ITCs significantly induced stomatal closure, where PEITC and BITC were most effective. The selected ITCs also induced ROS accumulation, cytosolic alkalization, and GSH depletion in guard cells. Moreover, all ITCs increased the frequency of cytosolic free calcium ([Ca2+]cyt) spikes (transient elevation), while PEITC and BITC showed the highest frequency. There was a strong positive correlation between the number of [Ca2+]cyt spikes per guard cell and the decrease in stomatal aperture. Both cytosolic alkalization and GSH content have a positive correlation with the decrease in stomatal aperture, but ROS production did not have a significant correlation with the decrease in stomatal apertures. These results indicate that the molecules with a functional ITC group induce stomatal closure that is accompanied by GSH depletion, cytosolic alkalization, [Ca2+]cyt spikes, and ROS production, and that the former three cellular events, rather than ROS production, are highly correlated with the decrease in stomatal aperture.

DOI： 10.1093/jxb/eraa420

Fucoxanthin activities motivate its nano/micro-encapsulation for food or nutraceutical application: a review. Reviewed International journal

Chunyan Wang, Xing Chen, Yoshimasa Nakamura, Chenxu Yu, Hang Qi

Food & function 11 ( 11 ) 9338 - 9358 2020.11

Language：English Publishing type：Research paper (scientific journal)

Fucoxanthin is a xanthophyll carotenoid abundant in marine brown algae. The potential therapeutic effects of fucoxanthin on tumor intervention have been well documented, which have aroused great interests in utilizing fucoxanthin in functional foods and nutraceuticals. However, the utilization of fucoxanthin as a nutraceutical in food and nutrient supplements is currently limited due to its low water solubility, poor stability, and limited bioaccessibility. Nano/micro-encapsulation is a technology that can overcome these challenges. A systematic review on the recent progresses in nano/micro-delivery systems to encapsulate fucoxanthin in foods or nutraceuticals is warranted. This article starts with a brief introduction of fucoxanthin and the challenges of oral delivery of fucoxanthin. Nano/micro-encapsulation technology is then covered, including materials and strategies for constructing the delivery system. Finally, future prospective has been discussed on properly designed oral delivery systems of fucoxanthin for managing cancer. Natural edible materials such as whey protein, casein, zein, gelatin, and starch have been successfully utilized to fabricate lipid-based, gel-based, or emulsion-based delivery systems, molecular nanocomplexes, and biopolymer nanoparticles with the aid of advanced processing techniques, such as freeze-drying, high pressure homogenization, sonication, anti-solvent precipitation, coacervation, ion crosslinking, ionic gelation, emulsification, and enzymatic conjugation. These formulated nano/micro-capsules have proven to be effective in stabilizing and enhancing the bioaccessibility of fucoxanthin. This review will inspire a surge of multidisciplinary research in a broader community of foods and motivate material scientists and researchers to focus on nano/micro-encapsulated fucoxanthin in order to facilitate the commercialization of orally-deliverable tumor intervention products.

DOI： 10.1039/d0fo02176h

Exogenous proline enhances antioxidant enzyme activities but does not mitigate growth inhibition by selenate stress in tobacco BY-2 cells. Reviewed International journal

Mousumi Khatun, Daiki Matsushima, Mohammad Saidur Rhaman, Eiji Okuma, Toshiyuki Nakamura, Yoshimasa Nakamura, Shintaro Munemasa, Yoshiyuki Murata

Bioscience, biotechnology, and biochemistry 84 ( 11 ) 2281 - 2292 2020.11

Language：English Publishing type：Research paper (scientific journal)

Selenium (Se) causes oxidative damage to plants. Proline is accumulated as a compatible solute in plants under stress conditions and mitigates stresses. Selenate at 250 µM increased cell death and inhibited the growth of tobacco BY-2 cells while exogenous proline at 10 mM did not mitigate the inhibition by selenate. Selenate increased accumulation of Se and ROS and activities of antioxidant enzymes but not lipid peroxidation in the BY-2 cells. Proline increased Se accumulation and antioxidant enzyme activities but not either ROS accumulation or lipid peroxidation in the selenate-stressed cells. Glutathione (GSH) rather than ascorbic acid (AsA) mitigated the growth inhibition although both reduced the accumulation of ROS induced by selenate. These results indicate that proline increases both antioxidant enzyme activities and Se accumulation, which overall fails to ameliorate the growth inhibition by selenate and that the growth inhibition is not accounted for only by ROS accumulation. Abbreviations: APX: ascorbate peroxidase; AsA: ascorbic acid; BY-2: Bright Yellow-2; CAT: catalase; DAI: days after inoculation; DW: dry weight; FW: fresh weight; GSH: glutathione; ROS: reactive oxygen species.

DOI： 10.1080/09168451.2020.1799747

Inhibition of Drug Resistance Mechanisms Improves the Benzyl Isothiocyanate–Induced Anti-Proliferation in Human Colorectal Cancer Cells Invited Reviewed

Xiaoyang Liu, Qifu Yang, Yoshimasa Nakamura

Current Pharmacology Reports 6 ( 5 ) 306 - 314 2020.10

Reactive carbonyl species mediate methyl jasmonate-induced stomatal closure. Reviewed

Md Moshiul Islam, Wenxiu Ye, Fahmida Akter, Mohammad Saidur Rhaman, Daiki Matsushima, Shintaro Munemasa, Eiji Okuma, Yoshimasa Nakamura, Md Sanaullah Biswas, Jun'ichi Mano, Yoshiyuki Murata

Plant & cell physiology 61 ( 10 ) 1788 - 1797 2020.8

Language：English Publishing type：Research paper (scientific journal)

Production of reactive oxygen species (ROS) is a key signal event for methyl jasmonate (MeJA)- and abscisic acid (ABA)-induced stomatal closure. We recently showed that reactive carbonyl species (RCS) stimulates stomatal closure as an intermediate downstream of hydrogen peroxide (H2O2) production in the ABA signaling pathway in guard cells of Nicotiana tabacum and Arabidopsis thaliana. In this study, we examined whether RCS functions as an intermediate downstream of H2O2 production in MeJA signaling in guard cells using transgenic tobacco plants overexpressing A. thaliana 2-alkenal reductase (n-alkanal + NAD(P)+ ⇌ 2-alkenal + NAD(P)H + H+) (AER-OE tobacco) and Arabidopsis plants. The stomatal closure induced by MeJA was impaired in the AER-OE tobacco and was inhibited by RCS scavengers, carnosine and pyridoxamine, in the wild-type (WT) tobacco plants and Arabidopsis plants. Application of MeJA significantly induced accumulation of RCS including acrolein and 4-hydroxy-(E)-2-nonenal in the WT tobacco but not in the AER-OE plants. Application of MeJA induced H2O2 production in the WT tobacco and the AER-OE plants and the H2O2 production was not inhibited by the RCS scavengers. These results suggest that RCS functions as an intermediate downstream of ROS production in MeJA signaling as well as in ABA signaling in guard cells.

DOI： 10.1093/pcp/pcaa107

Interaction of intracellular hydrogen peroxide accumulation with nitric oxide production in abscisic acid signaling in guard cells. Reviewed International journal

Rayhanur Jannat, Takanori Senba, Daichi Muroyama, Misugi Uraji, Mohammad Anowar Hossain, Mohammad Muzahidul Islam, Yoshimasa Nakamura, Shintaro Munemasa, Izumi C Mori, Yoshiyuki Murata

Bioscience, biotechnology, and biochemistry 84 ( 7 ) 1418 - 1426 2020.7

Language：English Publishing type：Research paper (scientific journal)

Reactive oxygen species and nitric oxide (NO•) concomitantly play essential roles in guard cell signaling. Studies using catalase mutants have revealed that the inducible and constitutive elevations of intracellular hydrogen peroxide (H2O2) have different roles: only the inducible H2O2 production transduces the abscisic acid (ABA) signal leading stomatal closure. However, the involvement of inducible or constitutive NO• productions, if exists, in this process remains unknown. We studied H2O2 and NO• mobilization in guard cells of catalase mutants. Constitutive H2O2 level was higher in the mutants than that in wild type, but constitutive NO• level was not different among lines. Induced NO• and H2O2 levels elicited by ABA showed a high correlation with each other in all lines. Furthermore, NO• levels increased by exogenous H2O2 also showed a high correlation with stomatal aperture size. Our results demonstrate that ABA-induced intracellular H2O2 accumulation triggers NO• production leading stomatal closure. ABBREVIATIONS: ABA: abscisic acid; CAT: catalase; cGMP: cyclic guanosine monophosphate; DAF-2DA: 4,5-diaminofluorescein-2 diacetate; H2DCF-DA: 2',7'-dichlorodihydrofluorescein diacetate; MeJA: methyljasmonate; NOS: nitric oxide synthetase; NR: nitrate reductase; POX: peroxidase; ROS: reactive oxygen species; SNAP: S-nitroso-N-acetyl-DL-penicillamine; SNP: sodium nitroprusside; NOX: NADP(H) oxidase.

DOI： 10.1080/09168451.2020.1743168

Inhibition of light-induced stomatal opening by allyl isothiocyanate does not require guard cell cytosolic Ca2+ signaling. Reviewed International journal

Wenxiu Ye, Eigo Ando, Mohammad Saidur Rhaman, Md Tahjib-Ul-Arif, Eiji Okuma, Yoshimasa Nakamura, Toshinori Kinoshita, Yoshiyuki Murata

Journal of experimental botany 71 ( 10 ) 2922 - 2932 2020.5

Language：English Publishing type：Research paper (scientific journal)

The glucosinolate-myrosinase system is a well-known defense system that has been shown to induce stomatal closure in Brassicales. Isothiocyanates are highly reactive hydrolysates of glucosinolates, and an isothiocyanate, allyl isothiocyanate (AITC), induces stomatal closure accompanied by elevation of free cytosolic Ca2+ concentration ([Ca2+]cyt) in Arabidopsis. It remains unknown whether AITC inhibits light-induced stomatal opening. This study investigated the role of Ca2+ in AITC-induced stomatal closure and inhibition of light-induced stomatal opening. AITC induced stomatal closure and inhibited light-induced stomatal opening in a dose-dependent manner. A Ca2+ channel inhibitor, La3+, a Ca2+chelator, EGTA, and an inhibitor of Ca2+ release from internal stores, nicotinamide, inhibited AITC-induced [Ca2+]cyt elevation and stomatal closure, but did not affect inhibition of light-induced stomatal opening. AITC activated non-selective Ca2+-permeable cation channels and inhibited inward-rectifying K+ (K+in) channels in a Ca2+-independent manner. AITC also inhibited stomatal opening induced by fusicoccin, a plasma membrane H+-ATPase activator, but had no significant effect on fusicoccin-induced phosphorylation of the penultimate threonine of H+-ATPase. Taken together, these results suggest that AITC induces Ca2+ influx and Ca2+ release to elevate [Ca2+]cyt, which is essential for AITC-induced stomatal closure but not for inhibition of K+in channels and light-induced stomatal opening.

DOI： 10.1093/jxb/eraa073

The Myrosinases TGG1 and TGG2 Function Redundantly in Reactive Carbonyl Species Signaling in Arabidopsis Guard Cells. Reviewed

Mohammad Saidur Rhaman, Toshiyuki Nakamura, Yoshimasa Nakamura, Shintaro Munemasa, Yoshiyuki Murata

Plant & cell physiology 61 ( 5 ) 967 - 977 2020.5

Language：English Publishing type：Research paper (scientific journal)

Myrosinase (β-thioglucoside glucohydrolase, enzyme nomenclature, EC 3.2.1.147, TGG) is a highly abundant protein in Arabidopsis guard cells, of which TGG1 and TGG2 function redundantly in abscisic acid (ABA)- and methyl jasmonate-induced stomatal closure. Reactive carbonyl species (RCS) are α,β-unsaturated aldehydes and ketones, which function downstream of reactive oxygen species (ROS) production in the ABA signalling pathway in guard cells. Among the RCS, acrolein is the most highly reactive, which is significantly produced in ABA-treated guard cells. To clarify the ABA signal pathway downstream of ROS production, we investigated the responses of tgg mutants (tgg1-3, tgg2-1 and tgg1-3 tgg2-1) to acrolein. Acrolein induced stomatal closure and triggered cytosolic alkalization in wild type (WT), tgg1-3 single mutants and in tgg2-1 single mutants, but not in tgg1-3 tgg2-1 double mutants. Exogenous Ca2+ induced stomatal closure and cytosolic alkalization not only in WT but also in all of the mutants. Acrolein- and Ca2+-induced stomatal closures were inhibited by an intracellular acidifying agent, butyrate, a Ca2+ chelator, ethylene glycol tetraacetic acid (EGTA) and a Ca2+ channel blocker, LaCl3. Acrolein induced cytosolic free calcium concentration ([Ca2+]cyt) elevation in guard cells of WT plants but not in the tgg1-3 tgg2-1 double mutants. Exogenous Ca2+ elicited [Ca2+]cyt elevation in guard cells of WT and tgg1-3 tgg2-1. Our results suggest that TGG1 and TGG2 function redundantly, not between ROS production and RCS production, but downstream of RCS production in the ABA signal pathway in Arabidopsis guard cells.

DOI： 10.1093/pcp/pcaa024

Salicylic acid receptor NPR1 is involved in guard cell chitosan signaling. Reviewed International journal

Yeasin Prodhan, Mohammad Issak, Shintaro Munemasa, Yoshimasa Nakamura, Yoshiyuki Murata

Bioscience, biotechnology, and biochemistry 84 ( 5 ) 963 - 969 2020.5

Language：English Publishing type：Research paper (scientific journal)

Chitosan (CHT) induces stomatal closure and thus plays a crucial role in plants to adapt to the adverse environments. Our previous results of a SA-deficient mutant nahG suggest that endogenous salicylic acid (SA) is involved in the CHT signaling in guard cells. Here in order to make the involvement definite, we examined stomatal responses to CHT of another SA-deficient mutant, sid2, and an SA receptor mutant, npr1-3. The sid2 mutation impaired CHT-induced stomatal closure and reactive oxygen species production and both impairments were complemented with exogenous SA application. Moreover, the CHT-induced stomatal closure is disrupted in the npr1-3 mutant. These results suggest that endogenous SA is involved in the CHT-induced stomatal closure via the SA receptor, NPR1.Abbreviations: SA: salicylic acid; ABA: abscisic acid; ROS: reactive oxygen species; NPR1: nonexpresser of pathogenesis-related genes1; CHT: chitosan; DAB: 3,3'-diaminobenzidine.

DOI： 10.1080/09168451.2020.1718485

Synthesis and characterization of conductive flexible cellulose carbon nanohorn sheets for human tissue applications. Reviewed International journal

Karthik Paneer Selvam, Taichi Nagahata, Kosuke Kato, Mayuko Koreishi, Toshiyuki Nakamura, Yoshimasa Nakamura, Takeshi Nishikawa, Ayano Satoh, Yasuhiko Hayashi

Biomaterials research 24 18 - 18 2020

Language：English Publishing type：Research paper (scientific journal)

Background: Conductive sheets of cellulose and carbon nanomaterials and its human skin applications are an interesting research aspect as they have potential for applications for skin compatibility. Hence it is needed to explore the effects and shed light on these applications. Method: To fabricate wearable, portable, flexible, lightweight, inexpensive, and biocompatible composite materials, carbon nanohorns (CNHs) and hydroxyethylcellulose (HEC) were used as precursors to prepare CNH-HEC (Cnh-cel) composite sheets. Cnh-cel sheets were prepared with different loading concentrations of CNHs (10, 20 50,100 mg) in 200 mg cellulose. To fabricate the bio-compatible sheets, a pristine composite of CNHs and HEC was prepared without any pretreatment of the materials. Results: The obtained sheets possess a conductivity of 1.83 × 10- 10 S/m and bio-compatible with human skin. Analysis for skin-compatibility was performed for Cnh-cel sheets by h-CLAT in vitro skin sensitization tests to evaluate the activation of THP-1 cells. It was found that THP-1 cells were not activated by Cnh-cel; hence Cnh-cel is a safe biomaterial for human skin. It was also found that the composite allowed only a maximum loading of 100 mg to retain the consistent geometry of free-standing sheets of < 100 μm thickness. Since CNHs have a unique arrangement of aggregates (dahlia structure), the composite is homogeneous, as verified by transmission electron microscopy (TEM) and, scanning electron microscopy (SEM), and other functional properties investigated by Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), conductivity measurement, tensile strength measurement, and skin sensitization. Conclusion: It can be concluded that cellulose and CNHs sheets are conductive and compatible to human skin applications.

DOI： 10.1186/s40824-020-00194-3

Isolation and identification of zinc-chelating peptides from sea cucumber (Stichopus japonicus) protein hydrolysate. Reviewed

Liu X, Wang Z, Zhang J, Song L, Li D, Wu Z, Zhu B, Nakamura Y, Shahidi F, Yu C, Zhou D

Journal of the science of food and agriculture 99 ( 14 ) 6400 - 6407 2019.11

Dynamics of the Cellular Metabolism of Leptosperin Found in Manuka Honey. Reviewed International journal

Yoji Kato, Masaki Kawai, Shota Kawai, Yayako Okano, Natsumi Rokkaku, Akari Ishisaka, Kaeko Murota, Toshiyuki Nakamura, Yoshimasa Nakamura, Shinichi Ikushiro

Journal of agricultural and food chemistry 67 ( 39 ) 10853 - 10862 2019.10

Language：English Publishing type：Research paper (scientific journal)

Leptosperin (methyl syringate β-d-gentiobioside) is abundantly found in manuka honey, which is widely used because of its antibacterial and possible anti-inflammatory activities. The aim of this study was to examine the molecular mechanism underlying the metabolism of leptosperin. Five phytochemicals (leptosperin, methyl syringate (MSYR), glucuronate conjugate of MSYR (MSYR-GA), sulfonate conjugate of MSYR (MSYR-S), and syringic acid (SYR)) were separately incubated with HepG2 and Caco-2 cells. After incubation, we found that the concentration of MSYR decreased, whereas the concentrations of SYR, MSYR-GA, and MSYR-S increased. By profiling with inhibitors and carboxylesterases (CES1, 2), we found that the conversion from MSYR to SYR was mediated by CES1. Lipopolysaccharide-stimulated RAW264.7 cells restored MSYR-GA to MSYR possibly by the secreted β-glucuronidase. All of the mice administered with leptosperin, MSYR, or manuka honey showed higher MSYR (13.84 ± 11.51, 14.29 ± 9.19, or 6.66 ± 2.30 nM) and SYR (1.85 ± 0.66, 6.01 ± 1.20, or 8.16 ± 3.10 nM) levels in the plasma compared with that of the vehicle controls (3.33 ± 1.45 (MSYR) and 1.85 ± 0.66 (SYR) nM). The findings of our study indicate that the unique metabolic pathways of these compounds may account for possible functionalities of manuka honey.

DOI： 10.1021/acs.jafc.9b03894

Ethylene Inhibits Methyl Jasmonate-Induced Stomatal Closure by Modulating Guard Cell Slow-Type Anion Channel Activity via the OPEN STOMATA 1/SnRK2.6 Kinase-Independent Pathway in Arabidopsis. Reviewed

Munemasa S, Hirao Y, Tanami K, Mimata Y, Nakamura Y, Murata Y

Plant & cell physiology 60 ( 10 ) 2263 - 2271 2019.10

Language：English Publishing type：Research paper (scientific journal)

Signal crosstalk between jasmonate and ethylene is crucial for a proper maintenance of defense responses and development. Although previous studies reported that both jasmonate and ethylene also function as modulators of stomatal movements, the signal crosstalk mechanism in stomatal guard cells remains unclear. Here, we show that the ethylene signaling inhibits jasmonate signaling as well as abscisic acid (ABA) signaling in guard cells of Arabidopsis thaliana and reveal the signaling crosstalk mechanism. Both an ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) and an ethylene-releasing compound ethephon induced transient stomatal closure, and also inhibited methyl jasmonate (MeJA)-induced stomatal closure as well as ABA-induced stomatal closure. The ethylene inhibition of MeJA-induced stomatal closure was abolished in the ethylene-insensitive mutant etr1-1, whereas MeJA-induced stomatal closure was impaired in the ethylene-overproducing mutant eto1-1. Pretreatment with ACC inhibited MeJA-induced reactive oxygen species (ROS) production as well as ABA-induced ROS production in guard cells but did not suppress ABA activation of OPEN STOMATA 1 (OST1) kinase in guard cell-enriched epidermal peels. The whole-cell patch-clamp analysis revealed that ACC attenuated MeJA and ABA activation of S-type anion channels in guard cell protoplasts. However, MeJA and ABA inhibitions of Kin channels were not affected by ACC pretreatment. These results suggest that ethylene signaling inhibits MeJA signaling and ABA signaling by targeting S-type anion channels and ROS but not OST1 kinase and K+ channels in Arabidopsis guard cells.

DOI： 10.1093/pcp/pcz121

Zinc-Chelating Mechanism of Sea Cucumber (Stichopus japonicus)-Derived Synthetic Peptides Reviewed

Xiaoyang Liu, Zixu Wang, Fawen Yin, Yuxin Liu, Ningbo Qin, Yoshimasa Nakamura, Fereidoon Shahidi, Chenxu Yu, Dayong Zhou, Beiwei Zhu

Marine Drugs 17 ( 8 ) 2019.7

Reactive carbonyl species function as signal mediators downstream of H<inf>2</inf>O<inf>2</inf> production and regulate [Ca²⁺]<inf>cyt</inf> elevation in ABA signal pathway in Arabidopsis guard cells Reviewed

Md Moshiul Islam, Wenxiu Ye, Daiki Matsushima, Mohammad Saidur Rhaman, Shintaro Munemasa, Eiji Okuma, Yoshimasa Nakamura, Md Sanaullah Biswas, Jun'ichi Mano, Yoshiyuki Murata

Plant and Cell Physiology 60 ( 5 ) 1146 - 1159 2019.5

Publishing type：Research paper (scientific journal)

© The Author(s) 2019. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. We have demonstrated that reactive carbonyl species (RCS) function as an intermediate downstream of hydrogen peroxide (H2O2) production in abscisic acid (ABA) signaling for stomatal closure in guard cells using transgenic tobacco plants overexpressing alkenal reductase. We investigated the conversion of the RCS production into downstream signaling events in the guard cells. Both ABA and H2O2 induced production of the RCS, such as acrolein and 4-hydroxy-(E)-2-nonenal (HNE), in epidermal tissues of wild-type Arabidopsis thaliana plants. Application of the RCS scavengers, carnosine and pyridoxamine, did not affect the ABA-induced H2O2 production but inhibited the ABA- and H2O2-induced stomatal closure. Both acrolein and HNE induced stomatal closure in a plasma membrane NAD(P)H oxidase mutant atrbohD atrbohF as well as in the wild type, but not in a calcium-dependent kinase mutant cpk6. Acrolein activated plasma membrane Ca2+-permeable cation channels, triggered cytosolic free Ca2+ concentration ([Ca2+]cyt) elevation, and induced stomatal closure accompanied by depletion of glutathione in the guard cells. These results suggest that RCS production is a signaling event between the ROS production and [Ca2+]cyt elevation during guard cell ABA signaling.

DOI： 10.1093/pcp/pcz031

Covalent modification of phosphatidylethanolamine by benzyl isothiocyanate and the resultant generation of ethanolamine adduct as its metabolite. Reviewed International journal

Nakamura T, Hirakawa M, Nakamura Y, Ishisaka A, Kitamoto N, Murakami A, Kato Y

Chemical research in toxicology 32 ( 4 ) 638 - 644 2019.2

Language：English Publishing type：Research paper (scientific journal)

Benzyl isothiocyanate (BITC), a dietary isothiocyanate (ITC) derived from cruciferous vegetables, has anticancer properties. It is believed that the ITC moiety (-N═C═S) that reacts predominantly with thiol compounds plays a central role in triggering the activities resulting from these properties. Recent studies have demonstrated that ITCs also covalently modify amino moieties in a protein. In this study, we examined the chemical reaction between BITC and the aminophospholipid, phosphatidylethanolamine (PE), in the cell membrane or lipoprotein particle. To detect the BITC-modified PE, the bond between ethanolamine (EA) and phosphatidic acid in PE was cleaved using phospholipase D to form the BITC-EA adduct, which was then measured. BITC-EA was detected from the BITC-treated unilamellar liposome and low-density lipoprotein even with only a few micromoles of BITC treatment, suggesting that BITC might react with not only a thiol/amino group of a protein but also an amino moiety of an aminophospholipid. Moreover, after incorporating BITC-PE included in the liposomes into the cultured cells or after direct exposure of BITC to the cells, free BITC-EA was excreted and accumulated in the medium in a time-dependent manner. It indicates that an intracellular enzyme catalyzes the cleavage of BITC-PE to produce BITC-EA. Because the ITC-amine adduct is stable, the ITC-EA adduct could be a promising indicator of ITC exposure in vivo.

DOI： 10.1021/acs.chemrestox.8b00331

The Golgin Protein Giantin Regulates Interconnections Between Golgi Stacks. Reviewed International journal

Ayano Satoh, Mitsuko Hayashi-Nishino, Takuto Shakuno, Junko Masuda, Mayuko Koreishi, Runa Murakami, Yoshimasa Nakamura, Toshiyuki Nakamura, Naomi Abe-Kanoh, Yasuko Honjo, Joerg Malsam, Sidney Yu, Kunihiko Nishino

Frontiers in cell and developmental biology 7 ( AUG ) 160 - 160 2019

Language：English Publishing type：Research paper (scientific journal)

Golgins are a family of Golgi-localized long coiled-coil proteins. The major golgin function is thought to be the tethering of vesicles, membranes, and cytoskeletal elements to the Golgi. We previously showed that knockdown of one of the longest golgins, Giantin, altered the glycosylation patterns of cell surfaces and the kinetics of cargo transport, suggesting that Giantin maintains correct glycosylation through slowing down transport within the Golgi. Giantin knockdown also altered the sizes and numbers of mini Golgi stacks generated by microtubule de-polymerization, suggesting that it maintains the independence of individual Golgi stacks. Therefore, it is presumed that Golgi stacks lose their independence following Giantin knockdown, allowing easier and possibly increased transport among stacks and abnormal glycosylation. To gain structural insights into the independence of Golgi stacks, we herein performed electron tomography and 3D modeling of Golgi stacks in Giantin knockdown cells. Compared with control cells, Giantin-knockdown cells had fewer and smaller fenestrae within each cisterna. This was supported by data showing that the diffusion rate of Golgi membrane proteins is faster in Giantin-knockdown Golgi, indicating that Giantin knockdown structurally and functionally increases connectivity among Golgi cisternae and stacks. This increased connectivity suggests that contrary to the cis-golgin tether model, Giantin instead inhibits the tether and fusion of nearby Golgi cisternae and stacks, resulting in transport difficulties between stacks that may enable the correct glycosylation of proteins and lipids passing through the Golgi.

DOI： 10.3389/fcell.2019.00160

Benzyl isothiocyanate ameliorates lipid accumulation in 3T3-L1 preadipocytes during adipocyte differentiation. Reviewed

Liang Y, Sasaki I, Takeda Y, Zhu B, Munemasa S, Nakamura T, Murata Y, Nakamura Y

Bioscience, biotechnology, and biochemistry 82 ( 12 ) 2130 - 2139 2018.12

Authorship：Last author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：Oxford University Press (OUP)

<title>ABSTRACT</title>
Benzyl isothiocyanate (BITC) is an organosulfur compound derived from cruciferous vegetables and papaya seeds. In this study, we investigated the effect of BITC on the lipid accumulation in 3T3-L1 preadipocytes during adipocyte differentiation. The treatment of BITC during the differentiation-inducing stage significantly ameliorated the lipid accumulation, whereas it had no inhibitory effect during the differentiation-maintaining stage. BITC also significantly suppressed the mRNA expression of the adipocyte-specific markers, such as CCAAT/enhancer-binding protein α (C/EBPα), C/EBPβ, C/EBPδ and peroxisome proliferator-activated receptor γ. BITC significantly inhibited the phosphorylation of extracellular signal-regulated kinase phosphorylation, whereas it enhanced that of AMP-activated protein kinase. Furthermore, BITC significantly suppressed the intracellular 2-deoxyglucose uptake as well as glucose transporter 4 expression. These results suggest that inhibition of the adipocyte differentiation and glucose uptake may mainly contribute to the inhibitory effect of BITC on the lipid accumulation in 3T3-L1 preadipocytes.

Abbreviations: PPARγ: peroxisome proliferator-activated receptor γ; CEBP: CCAAT/enhancer-binding protein; GLUT4: glucose transporter 4; AMPK: AMP-activated protein kinase; ERK1/2: extracellular signal-regulated kinase 1/2; MAPK: a mitogen-activated protein kinase; ITCs: isothiocyanates; BITC: benzyl isothiocyanate; FBS: fetal bovine serum; CS: calf serum; AITC: allyl ITC; IBMX: 3-isobutyl-1-methylxanthine; LDH: lactate dehydrogenase; KRH: Krebs-Ringer-Hepes-bicarbonate; 2-DG: 2-deoxy-d-glucose

DOI： 10.1080/09168451.2018.1514247

Oxidative stress involved in textural changes of sea cucumber Stichopus japonicus body wall during low-temperature treatment. Reviewed

Dong X, Qi H, Feng D, He B, Nakamura Y, Yu C, Zhu B

Int. J. Food Prop. 21 ( 1 ) 2646 - 2659 2018.12

Methyl-β-cyclodextrin potentiates the BITC-induced anti-cancer effect through modulation of the Akt phosphorylation in human colorectal cancer cells. Reviewed

Yang Q, Miyagawa M, Liu X, Zhu B, Munemasa S, Nakamura T, Murata Y, Nakamura Y

Bioscience, biotechnology, and biochemistry 82 ( 12 ) 2158 - 2167 2018.12

Authorship：Last author,　Corresponding author Publishing type：Research paper (scientific journal) Publisher：Oxford University Press (OUP)

<title>ABSTRACT</title>
Methyl-β-cyclodextrin (MβCD) is an effective agent for the removal of plasma membrane cholesterol. In this study, we investigated the modulating effects of MβCD on the antiproliferation induced by benzyl isothiocyanate (BITC), an ITC compound mainly derived from papaya seeds. We confirmed that MβCD dose-dependently increased the cholesterol level in the medium, possibly through its removal from the plasma membrane of human colorectal cancer cells. The pretreatment with a non-toxic concentration (2.5 mM) of MβCD significantly enhanced the BITC-induced cytotoxicity and apoptosis induction, which was counteracted by the cholesterol supplementation. Although BITC activated the phosphoinositide 3-kinase (PI3K)/Akt pathway, MβCD dose-dependently inhibited the phosphorylation level of Akt. On the contrary, the treatment of MβCD enhanced the phosphorylation of mitogen activated protein kinases, but did not potentiate their BITC-induced phosphorylation. These results suggested that MβCD might potentiate the BITC-induced anti-cancer by cholesterol depletion and thus inhibition of the PI3K/Akt-dependent survival pathway.

Abbreviations: CDs: cyclodextrins; MβCD: methyl-β-cyclodextrin; ITCs: isothiocyanates; BITC: benzyl isothiocyanate; PI3K: phosphoinositide 3-kinase; PDK1: phosphoinositide-dependent kinase-1; MAPK: mitogen activated protein kinase; ERK1/2: extracellular signal-regulated kinase1/2; JNK: c-Jun N-terminal kinase; PI: propidium iodide; FBS: fatal bovine serum; TLC: thin-layer chromatography; PBS(-): phosphate-buffered saline without calcium and magnesium; MEK: MAPK/ERK kinase; PIP2: phosphatidylinositol-4,5-bisphosphate; PIP3: phosphatidylinositol-3,4,5-trisphosphate

DOI： 10.1080/09168451.2018.1514249

Lycii fructus extract ameliorates hydrogen peroxide-induced cytotoxicity through indirect antioxidant action. Reviewed

Xu W, Saiki S, Myojin T, Liu Y, Zhu B, Murata Y, Ashida H, Tsunenaga M, Nakamura Y

Bioscience, biotechnology, and biochemistry 82 ( 10 ) 1812 - 1820 2018.10

Guard Cell Salicylic Acid Signaling Is Integrated into Abscisic Acid Signaling via the Ca²⁺/CPK-Dependent Pathway. Reviewed

Prodhan MY, Munemasa S, Nahar MN, Nakamura Y, Murata Y

Plant physiology 178 ( 1 ) 441 - 450 2018.9

Lymphatic metabolites of quercetin after intestinal administration of quercetin-3-glucoside and its aglycone in rats Reviewed

Toshiyuki Nakamura, Chinatsu Kinjo, Yoshimasa Nakamura, Yoji Kato, Miyu Nishikawa, Masahiro Hamada, Noriyuki Nakajima, Shinichi Ikushiro, Kaeko Murota

ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 645 126 - 136 2018.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

Quercetin is a major flavonoid, present as its glycosidic forms in plant foods. In this study, quercetin-3-glucoside (Q3G) was administered intraduodenally to thoracic lymph-cannulated rats, and its lymphatic transport was investigated. The resulting lymphatic and plasma metabolites were identified with LC-MS/MS and compared with those after administration of quercetin aglycone.The total concentration of quercetin metabolites in the lymph was about four times lower than that in the plasma, and quercetin and its methylated form isorhamnetin were detected as their glucuronides, sulfates and diglucuronides both in the lymph and the plasma after Q3G and quercetin administrations. The lymph levels of the glucuronides after Q3G administration were lower than those after quercetin administration, whereas those in the plasma showed the opposite pattern. Both the lymph and plasma levels of the sulfates after Q3G administration were lower than those after quercetin administration. Some of the intestinal metabolites like quercetin monoglucuronides were transported directly into the lymph and the hepatic metabolites like the diglucuronides were eventually transferred from the plasma into the lymph.These results indicate that the absorbed Q3G is partly transported into the intestinal lymph as quercetin metabolites. Deglycosylation in the enterocyte is also suggested to affect the subsequent metabolic pathways.

DOI： 10.1016/j.abb.2018.03.024

Benzyl isothiocyanate attenuates the hydrogen peroxide-induced interleukin-13 expression through glutathione S-transferase P induction in T lymphocytic leukemia cells. Reviewed

Tang Y, Naito S, Abe-Kanoh N, Ogawa S, Yamaguchi S, Zhu B, Murata Y, Nakamura Y

Journal of biochemical and molecular toxicology 32 ( 6 ) e22054 2018.4

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY

We investigated the effect of benzyl isothiocyanate (BITC) on the hydrogen peroxide-induced gene expression of a T-helper-2 cytokine, interleukin (IL)-13, in T lymphocytic leukemia Jurkat cells. The 24-h pretreatment of BITC significantly inhibited the IL-13 expression enhanced by hydrogen peroxide. Although the BITC pretreatment did not change the enhanced level of the phosphorylated c-Jun N-terminal kinase (JNK), it significantly inhibited the nuclear translocation of c-Jun induced by hydrogen peroxide. BITC also increased the protein expression of glutathione S-transferase (GST) isozymes, GSTP1/2, as well as the total GST activity. A GSTP1/2 specific inhibitor, 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio) hexanol (NBDHEX), significantly counteracted the inhibitory effect of BITC on the hydrogen peroxide-enhanced IL-13 upregulation as well as the c-Jun nuclear translocation. Taken together, these results suggested that BITC inhibits the oxidative stress-mediated IL-13 mRNA expression, possibly through interference of the c-Jun phosphorylation by GSTP.

DOI： 10.1002/jbt.22054

Phenethyl isothiocyanate activates leptin signaling and decreases food intake. Reviewed International journal

Miho Yagi, Yukiko Nakatsuji, Ayumi Maeda, Hiroki Ota, Ryosuke Kamikubo, Noriyuki Miyoshi, Yoshimasa Nakamura, Mitsugu Akagawa

PloS one 13 ( 11 ) e0206748 2018

Language：English Publishing type：Research paper (scientific journal)

Obesity, a principal risk factor for the development of diabetes mellitus, heart disease, and hypertension, is a growing and serious health problem all over the world. Leptin is a weight-reducing hormone produced by adipose tissue, which decreases food intake via hypothalamic leptin receptors (Ob-Rb) and the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway. Protein tyrosine phosphatase 1B (PTP1B) negatively regulates leptin signaling by dephosphorylating JAK2, and the increased activity of PTP1B is implicated in the pathogenesis of obesity. Hence, inhibition of PTP1B may help prevent and reduce obesity. In this study, we revealed that phenethyl isothiocyanate (PEITC), a naturally occurring isothiocyanate in certain cruciferous vegetables, potently inhibits recombinant PTP1B by binding to the reactive cysteinyl thiol. Moreover, we found that PEITC causes the ligand-independent phosphorylation of Ob-Rb, JAK2, and STAT3 by inhibiting cellular PTP1B in differentiated human SH-SY5Y neuronal cells. PEITC treatment also induced nuclear accumulation of phosphorylated STAT3, resulting in enhanced anorexigenic POMC expression and suppressed orexigenic NPY/AGRP expression. We demonstrated that oral administration of PEITC to mice significantly reduces food intake, and stimulates hypothalamic leptin signaling. Our results suggest that PEITC might help prevent and improve obesity.

DOI： 10.1371/journal.pone.0206748

(-)-Epigallocatechin-3-gallate inhibits human angiotensin-converting enzyme activity through an autoxidation-dependent mechanism Reviewed

Zhe Liu, Sayaka Nakashima, Toshiyuki Nakamura, Shintaro Munemasa, Yoshiyuki Murata, Yoshimasa Nakamura

JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY 31 ( 9 ) 2017.9

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY

We investigated the molecular mechanisms involved in the angiotensin-converting enzyme (ACE) inhibition by (-)-epigallocatechin-3-gallate (EGCg), a major tea catechin. EGCg inhibited both the ACE activity in the lysate of human colorectal cancer cells and human recombinant ACE (rh-ACE) in a dose-dependent manner. Co-incubation with zinc sulfate showed no influence on the rh-ACE inhibition by EGCg, whereas it completely counteracted the inhibitory effect of ethylenediaminetetraacetic acid, a chelating-type ACE inhibitor. Although hydrogen peroxide was produced by the autoxidation of EGCg, hydrogen peroxide itself had little effect on the ACE activity. Conversely, the co-incubation of EGCg with borate or ascorbic acid significantly diminished the EGCg inhibition. A redox-cycling staining experiment revealed that rh-ACE was covalently modified by EGCg. A Lineweaver-Burk plot analysis indicated that EGCg inhibited the ACE activity in a non-competitive manner. These results suggested that EGCg might allosterically inhibit the ACE activity through oxidative conversion into an electrophilic quinone.

DOI： 10.1002/jbt.21932

Inhibition of phosphatidylinositide 3-kinase ameliorates antiproliferation by benzyl isothiocyanate in human colon cancer cells Reviewed

Xiaoyang Liu, Chiaki Takano, Tomomi Shimizu, Shintaro Yokobe, Naomi Abe-Kanoh, Beiwei Zhu, Toshiyuki Nakamura, Shintaro Munemasa, Yoshiyuki Murata, Yoshimasa Nakamura

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 491 ( 1 ) 209 - 216 2017.9

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

In the present study, we clarified the role of phosphatidylinositide 3-kinase (PI3K) in antiproliferation induced by benzyl isothiocyanate (BITC) in human colorectal cancer cells. BITC simultaneously activated the PI3K/Akt/forkhead box 0 (FoxO) pathway, whereas it significantly inhibited the proliferation in human colorectal cancer cells. Inhibitory experiments using a PI3K selective inhibitor, LY294002 or NVP-BEZ235, significantly enhanced the BITC-induced antiproliferation and apoptotic cell population with the attenuation of the BITC-induced activation of the PI3K/Akt/FoxO survival pathway. Furthermore, BITC enhanced the insulin-activated PI3K/Akt/FoxO pathway, possibly through its inhibition of the protein tyrosine phosphatase 1B enzymatic activity. Taken together, these results suggested that the PI3K/Akt/FoxO pathway negatively regulates the BITC-induced antiproliferation in human colorectal cancer cells. (C) 2017 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2017.07.078

Methylglyoxal induces inhibition of growth, accumulation of anthocyanin, and activation of glyoxalase I and II in Arabidopsis thaliana Reviewed

Tahsina Sharmin Hoque, Misugi Uraji, Md Anamul Hoque, Yoshimasa Nakamura, Yoshiyuki Murata

JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY 31 ( 7 ) 2017.7

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY

Methylglyoxal (MG) is a highly reactive stress-related -ketoaldehyde and a physiological metabolite of glycolysis, which is accumulated in ample amount under stressful conditions. In the present study, the effect of different doses of MG on growth, anthocyanin production, MG contents, and activities of two types of glyoxalases (glyoxalase I and glyoxalase II) were examined in Arabidopsis seedlings. MG at 0.1 mM dose did not affect seedling growth, anthocyanin accumulation, MG contents, or activities of glyoxalases, whereas MG at 0.5 mM and 1 mM inhibited seedling growth and induced anthocyanin accumulation, MG accumulation, and glyoxalase (both I and II) activation. Therefore, MG can reduce plant growth as a toxic molecule and can stimulate stress responses as a signal molecule under stress conditions.

DOI： 10.1002/jbt.21901

Cytotoxic and cytoprotective effects of tryptamine-4,5-dione on neuronal cells: a double-edged sword Reviewed

Naoko Suga, Akira Murakami, Yoshimasa Nakamura, Akari Ishisaka, Noritoshi Kitamoto, Mikiko Ito, Yoji Kato

FREE RADICAL RESEARCH 51 ( 5 ) 545 - 553 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Serotonin (5-hydroxytryptamine) is a putative substrate for myeloperoxidase, which may convert it into the reactive quinone tryptamine-4,5-dione (TD). In this study, we found that the viability of human SH-SY5Y neuroblastoma cells treated with 25 mu M TD was increased to approximately 117%. On the other hand, the cell viability was significantly decreased by exposure to TD (150-200 mu M), with an increase in intracellular reactive oxygen species (ROS). Interestingly, pretreatment of SH-SY5Y cells with 100 mu M TD prevented cell death and suppressed intracellular ROS generation evoked by the addition of hydrogen peroxide (H2O2). Expression of the phase-II antioxidant enzyme NAD(P)H: quinone oxidoreductase 1 and haem oxygenase 1 were upregulated by TD at a concentration of 50-100 mu M. Nuclear factor erythroid 2-related factor 2 (Nrf2), the regulator of these enzyme, was translocated from the cytosol to the nucleus by 100 mu M TD. In summary, moderate concentrations of TD may increase the self-defence capacity of neuronal cells against oxidative stress.

DOI： 10.1080/10715762.2017.1331038

Inhibition of phosphatidylinositide 3-kinase impairs the benzyl isothiocyanate-induced accumulation of autophagic molecules and Nrf2 in human colon cancer cells Reviewed

Xiaoyang Liu, Naomi Abe-Kanoh, Yujia Liu, Beiwei Zhu, Shintaro Munemasa, Toshiyuki Nakamura, Yoshiyuki Murata, Yoshimasa Nakamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 81 ( 11 ) 2212 - 2215 2017

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

The regulating role of phosphatidylinositide 3-kinase (PI3K) in benzyl isothiocyanate (BITC)-induced Nrf2 activation, contributing to the inducible expression of cytoprotective genes, was investigated. BITC significantly enhanced the accumulation of Nrf2 as well as autophagic molecules in human colorectal cancer HCT-116 cells. Experiments using a PI3K-specific inhibitor suggested that PI3K plays the key role in the non-canonical Nrf2 activation by BITC.

DOI： 10.1080/09168451.2017.1374830

3,4-Dihydroxyphenylacetic acid is a potential aldehyde dehydrogenase inducer in murine hepatoma Hepa1c1c7 cells Reviewed

Yujia Liu, Ayuki Kurita, Sayaka Nakashima, Beiwei Zhu, Shintaro Munemasa, Toshiyuki Nakamura, Yoshiyuki Murata, Yoshimasa Nakamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 81 ( 10 ) 1978 - 1983 2017

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

3,4-Dihydroxyphenylacetic acid (DOPAC) is one of the major colonic microflora-produced catabolites of quercetin glycosides, such as quercetin 4-glucoside derived from onion. Here, we investigated whether DOPAC modulates the aldehyde dehydrogenase (ALDH) activity and protects the cells from the acetaldehyde-induced cytotoxicity in vitro. DOPAC was shown to enhance not only the total ALDH activity, but also the gene expression of ALDH1A1, ALDH2 and ALDH3A1 in a concentration-dependent manner. DOPAC simultaneously stimulated the nuclear translocation of NFE2-related factor 2 and aryl hydrocarbon receptor. The pretreatment of DOPAC completely protected the cells from the acetaldehyde-induced cytotoxicity. The present study suggested that DOPAC acts as a potential ALDH inducer to prevent the alcohol-induced abnormal reaction.

DOI： 10.1080/09168451.2017.1361809

MPK9 and MPK12 function in SA-induced stomatal closure in Arabidopsis thaliana Reviewed

Md. Atiqur Rahman Khokon, Mohammad Abdus Salam, Fabien Jammes, Wenxiu Ye, Mohammad Anowar Hossain, Eiji Okuma, Yoshimasa Nakamura, Izumi C. Mori, June M. Kwak, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 81 ( 7 ) 1394 - 1400 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Salicylic acid (SA) induces stomatal closure sharing several components with abscisic acid (ABA) and methyl jasmonate (MeJA) signaling. We have previously shown that two guard cell-preferential mitogen-activated protein kinases (MAPKs), MPK9 and MPK12, positively regulate ABA signaling and MeJA signaling in Arabidopsis thaliana. In this study, we examined whether these two MAPKs are involved in SA-induced stomatal closure using genetic mutants and a pharmacological, MAPKK inhibitor. Salicylic acid induced stomatal closure in mpk9 and mpk12 single mutants but not in mpk9 mpk12 double mutants. The MAPKK inhibitor PD98059 inhibited SA-induced stomatal closure in wild-type plants. Salicylic acid induced extracellular reactive oxygen species (ROS) production, intracellular ROS accumulation, and cytosolic alkalization in the mpk9, mpk12, and mpk9 mpk12 mutants. Moreover, SA-activated S-type anion channels in guard cells of wild-type plants but not in guard cells of mpk9 mpk12 double mutants. These results imply that MPK9 and MPK12 are positive regulators of SA signaling in Arabidopsis guard cells.

DOI： 10.1080/09168451.2017.1308244

Exogenous proline enhances the sensitivity of Tobacco BY-2 cells to arsenate Reviewed

Mst Nur-E-Nazmun Nahar, Mohammad Muzahidul Islam, Md. Anamul Hoque, Anna Yonezawa, Md. Yeasin Prodhan, Toshiyuki Nakamura, Yoshimasa Nakamura, Shintaro Munemasa, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 81 ( 9 ) 1726 - 1731 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Arsenic causes physiological and structural disorders in plants. Proline is accumulated as a compatible solute in plants under various stress conditions and mitigates stresses. Here, we investigated the effects of exogenous proline on tobacco Bright Yellow-2 (BY-2) cultured cells under AsO4- stress. Arsenate did not inhibit BY-2 cell growth at 40 and 50 mu M but did it at 60 mu M. Proline at 0.5 to 10 mM did not affect the cell growth but delayed it at 20 mM. At 40 mu M AsO4-, neither 0.5 mM nor 1 mM proline affected the cell growth but 10 mM proline inhibited it. In the presence of AsO4-, 10 mM proline increased the number of Evans Blue-stained (dead) cells and decreased the number of total cells. Together, our results suggest that exogenous proline does not alleviate arsenate toxicity but enhances the sensitivity of BY-2 cells to arsenate.

DOI： 10.1080/09168451.2017.1340088

Chitosan signaling in guard cells requires endogenous salicylic acid Reviewed

Md. Yeasin Prodhan, Mohammad Issak, Toshiyuki Nakamura, Shintaro Munemasa, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 81 ( 8 ) 1536 - 1541 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

An elicitor chitosan (CHT) induces stomatal closure but the mechanism remains to be clarified. A phytohormone salicylic acid (SA) is crucial for elicitor-induced defense signaling in plants. Here we investigated whether endogenous SA is required for CHT signaling in guard cells. In the SA-deficient nahG mutant, treatment of CHT did not induce either apoplastic reactive oxygen species (ROS) production or stomatal closure but co-treatment of CHT and SA induced both apoplastic ROS production and stomatal closure, indicating the involvement of endogenous SA in CHT-induced apoplastic ROS production and CHT-induced stomatal closure. Furthermore, CHT induced transient cytosolic free calcium concentration increments in the nahG mutant in the presence of exogenous SA but not in the absence of exogenous SA. These results provide evidence that endogenous SA is a crucial element in CHT-induced stomatal closure.

DOI： 10.1080/09168451.2017.1332979

Reactive Carbonyl Species Mediate ABA Signaling in Guard Cells Reviewed

Md. Moshiul Islam, Wenxiu Ye, Daiki Matsushima, Shintaro Munemasa, Eiji Okuma, Yoshimasa Nakamura, Md. Sanaullah Biswas, Jun'ichi Mano, Yoshiyuki Murata

PLANT AND CELL PHYSIOLOGY 57 ( 12 ) 2552 - 2563 2016.12

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Drought is responsible for a massive reduction in crop yields. In response to drought, plants synthesize the hormone ABA, which induces stomatal closure, thus reducing water loss. In guard cells, ABA triggers production of reactive oxygen species (ROS), which is mediated by NAD(P) H oxidases. The production of ROS is a key factor for ABA-induced stomatal closure, but it remains to be clarified how the production of ROS is transduced into downstream signaling components in guard cells. We investigated roles of reactive carbonyl species (RCS) in ABA-induced stomatal closure using transgenic tobacco (Nicotiana tabacum) overexpressing Arabidopsis 2-alkenal reductase (AER-OE), which scavenges RCS. ABA and hydrogen peroxide (H2O2) induced accumulation of RCS including acrolein and 4-hydroxy-(E)-2-nonenal in wild-type tobacco but not in AER-OE. Stomatal closure and RCS accumulation in response to ABA and H2O2 were inhibited in AER-OE unlike in the wild type, while ABA-induced H2O2 production in guard cells was observed in AER-OE as well as in the wild type. Moreover, ABA inhibited inward-rectifying K+ channels in wild-type guard cells but not in AER-OE guard cells. These results suggest that RCS is involved in ABAinduced stomatal closure and functions downstream of H2O2 production in the ABA signaling pathway in guard cells.

DOI： 10.1093/pcp/pcw166

Galloylated Catechins as Potent Inhibitors of Angiotensin Converting Enzyme Reviewed

Zhe Liu, Toshiyuki Nakamura, Shintaro Munemasa, Yoshiyuki Murata, Yoshimasa Nakamura

FOOD SCIENCE AND TECHNOLOGY RESEARCH 22 ( 6 ) 847 - 851 2016.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：KARGER

In the present study, we investigated the inhibitory effects of four tea catechins, including (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg) and (-)-epigallocatechin gallate (EGCg), on angiotensin converting enzyme (ACE) activity in vitro. Each catechin treatment significantly reduced the ACE activity with the order of potency being EGCg > ECg > EGC = EC. The addition of 1 mM borate significantly recovered the reduced ACE activities by tea catechins, suggesting that hydroxyl groups at the B-ring or at a galloyl moiety play an important role in the ACE-inhibitory mechanism. The covalent modification of ACE by tea catechins was also observed by a redox-cycling staining experiment. A Lineweaver-Burk plot indicated that EGC and ECg were noncompetitive inhibitors. The galloylated catechins might more potently inhibit ACE activity in an allosteric manner through the interaction of the galloyl moiety with the non-catalytic site of ACE.

DOI： 10.3136/fstr.22.847

A novel tag-free probe for targeting molecules interacting with a flavonoid catabolite Reviewed

Sayaka Nakashima, Zhe Liu, Yuya Yamaguchi, Shunya Saiki, Shintaro Munemasa, Toshiyuki Nakamura, Yoshiyuki Murata, Yoshimasa Nakamura

Biochemistry and Biophysics Reports 7 240 - 245 2016.9

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier B.V.

3,4-Dihydroxyphenylacetic acid (DOPAC) is one of the colonic microflora-produced catabolites of quercetin 4'-glucoside (Q4'G). Although the interaction of DOPAC with cellular proteins might be involved in its biological activity, the actual proteins have not yet been identified. In this study, we developed a novel tag-free DOPAC probe to label the targeted proteins by the copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) and verified its efficacy. Various labeled proteins were detected by the DOPAC probe with the azide labeled biotin and a horseradish peroxidase (HRP)-streptavidin complex. Furthermore, a pulldown assay identified Keap1 and aryl hydrocarbon receptor (AhR) as the target proteins for the phase 2 enzyme up-regulation.

DOI： 10.1016/j.bbrep.2016.06.020

Involvement of OST1 Protein Kinase and PYR/PYL/RCAR Receptors in Methyl Jasmonate-Induced Stomatal Closure in Arabidopsis Guard Cells Reviewed

Ye Yin, Yuji Adachi, Yoshimasa Nakamura, Shintaro Munemasa, Izumi C. Mori, Yoshiyuki Murata

PLANT AND CELL PHYSIOLOGY 57 ( 8 ) 1779 - 1790 2016.8

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Methyl jasmonate (MeJA) induces stomatal closure. It has been shown that stomata of many ABA-insensitive mutants are also insensitive to MeJA, and a low amount of ABA is a prerequisite for the MeJA response. However, the molecular mechanisms of the interaction between ABA and MeJA signaling remain to be elucidated. Here we studied the interplay of signaling of the two hormones in guard cells using the quadruple ABA receptor mutant pyr1 pyl1 pyl2 pyl4 and ABA-activated protein kinase mutants ost1-2 and srk2e. In the quadruple mutant, MeJA-induced stomatal closure, H2O2 production, nitric oxide (NO) production, cytosolic alkalization and plasma membrane Ca2+-permeable current (I-Ca) activation were not impaired. At the same time, the inactivation of the inward-rectifying K+ current was impaired. In contrast to the quadruple mutant, MeJA-induced stomatal closure, H2O2 production, NO production and cytosolic alkalization were impaired in ost1-2 and srk2e as well as in aba2-2, the ABA-deficient mutant. The activation of ICa was also impaired in srk2e. Collectively, these results indicated that OST1 was essential for MeJA-induced stomatal closure, while PYR1, PYL1, PYL2 and PYL4 ABA receptors were not sufficient factors. MeJA did not appear to activate OST1 kinase activity. This implies that OST1 mediates MeJA signaling through an undetectable level of activity or a nonenzymatic action. MeJA induced the expression of an ABA synthesis gene, NCED3, and increased ABA contents only modestly. Taken together with previous reports, this study suggests that MeJA signaling in guard cells is primed by ABA and is not brought about through the pathway mediated by PYR1, PYL1 PYL2 and PYL4.

DOI： 10.1093/pcp/pcw102

Apoptosis induction is involved in UVA-induced autolysis in sea cucumber Stichopus japonicus Reviewed

Hang Qi, Hui Fu, Xiufang Dong, Dingding Feng, Nan Li, Chengrong Wen, Yoshimasa Nakamura, Beiwei Zhu

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 158 130 - 135 2016.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

Autolysis easily happens to sea cucumber (Stichopus japonicus, S. japonicus) for external stimulus like UV exposure causing heavy economic losses. Therefore, it is meaningful to reveal the mechanism of S. japonicas autolysis. In the present study, to examine the involvement of apoptosis induction in UVA-induced autolysis of S. japonicas, we investigated the biochemical events including the DNA fragmentation, caspase-3 activation, mitogen-activated protein kinases (MAPKs) phosphorylation and free radical formation. Substantial morphological changes such as intestine vomiting and dermatolysis were observed in S. japonicus during the incubation after 1-h UVA irradiation (10 W/m(2)). The degradation of the structural proteins and enhancement of cathepsin L activity were also detected, suggesting the profound impact of proteolysis caused by the UVA irradiation even for 1 h. Furthermore, the DNA fragmentation and specific activity of caspase-3 was increased up to 12 h after UVA irradiation. The levels of phosphorylated p38 mitogen activated protein kinase (MAPK) and phosphorylated c-jun.-N-terminal kinase (JNK) were significantly increased by the UVA irradiation for 1 h. An electron spin resonance (ESR) analysis revealed that UVA enhanced the free radical formation in S. japonicas, even through we could not identify the attributed species. These results suggest that UVA-induced autolysis in S. japonicas at least partially involves the oxidative stress-sensitive apoptosis induction pathway. These data present a novel insight into the mechanisms of sea cucumber autolysis induced by external stress. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jphotobiol.2016.02.034

A mushroom-derived amino acid, ergothioneine, is a potential inhibitor of inflammation-related DNA halogenation Reviewed

Takashi Asahi, Xiaohong Wu, Hiroshi Shimoda, Shinsuke Hisaka, Etsuko Harada, Tomomi Kanno, Yoshimasa Nakamura, Yoji Kato, Toshihiko Osawa

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 80 ( 2 ) 313 - 317 2016.2

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Myeloperoxidase (MPO)-generated halogenating molecules, such as hypochlorous acid and hypobromous acid (HOBr), in inflammatory regions are postulated to contribute to disease progression. In this study, we showed that ergothioneine (EGT), derived from an edible mushroom, inhibited MPO activity as well as the formation of 8-bromo-2-deoxyguanosine in vitro. The HOBr scavenging effect of EGT is higher than those of ascorbic acid and glutathione. We initially observed that the administration of Coprinus comatus, an edible mushroom containing a high amount of EGT, inhibited the UV-B-induced inflammatory responses and DNA halogenation, suggesting that EGT is a promising anti-inflammatory agent from mushrooms.

DOI： 10.1080/09168451.2015.1083396

Effects of Sodium Chloride and Ascorbic Acid on the Formation of Isothiocyanates in Two Types of Pickled Cruciferous Vegetables (Turnip, Chinese cabbage) Reviewed

Miyazawa Noriko, Abe Masako, Kimura Michiyo, Matsuoka Hiroki, Tanaka Susumu, Morimitsu Yasujirou, Nakamura Yoshimasa, Ayabe Sonoko, Ozawa Yoshio

Journal of Cookery Science of Japan 49 ( 2 ) 138 - 146 2016

Language：Japanese Publisher：一般社団法人日本調理科学会

Regular intake of vegetables suppresses the risk of lifestyle-related diseases. In Japan, a large amount of cruciferous vegetables that contain glucosinolates are consumed in cooked or pickled form. Glucosinolates are hydrolysed to isothiocyanates in plants by the enzyme myrosinase, which is released by tissue damage. Isothiocyanates have characteristic flavours and can inhibit carcinogenesis in some cases. In this study, we investigated the effects of NaCl and ascorbic acid concentration on myrosinase activity in vitro. Maximum myrosinase activity was observed for 1% NaCl or 0.1% ascorbic acid, although myrosinase activity was suppressed by a combination of NaCl and ascorbic acid. The degree of suppression of myrosinase activity decreased as the concentration of ascorbic acid increased.We prepared lightly pickled turnip and Chinese cabbage with final NaCl concentrations of 1%, 2%, and 3% to determine the effect of NaCl on isothiocyanate formation in pickles. 3-Butenyl, 4-pentenyl, and phenethyl isothiocyanate were detected by gas chromatography-mass spectrometry analyses; these compounds were formed in the highest amounts at 3% NaCl in both types of pickles. Moreover, the addition of 0.4% ascorbic acid increased the formation of isothiocyanate by 1.4-1.6 times compared with the control in both types of pickles. In sensory evaluation, panellists preferred the pickles with 2% NaCl.

DOI： 10.11402/cookeryscience.49.138

Plant Polyphenols as a Double-Edged Sword in Health Promotion : Lessons from the Experimental Models Using Simple Phenolic Acids Invited Reviewed

Agri-bioscience monographs AGBM 6 ( 1 ) 1 - 57 2016

Specific role of taurine in the 8-brominated-2 '-deoxyguanosine formation Reviewed

Takashi Asahi, Yoshimasa Nakamura, Yoji Kato, Toshihiko Osawa

ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 586 45 - 50 2015.11

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

At the sites of inflammation, hypohalous acids, such as hypochlorous acid and hypobromous acid (HOBr), are produced by myeloperoxidase. These hypohalous acids rapidly react with the primary amino groups to produce haloamines, which are relatively stable and can diffuse long distances and cross the plasma membrane. In this study, we examined the effects of taurine, the most abundant free amino acid in the leukocyte cytosol, on the hypohalous acid-dependent formation of 8-chloro-2'-deoxyguanosine (8-CldG) and 8-bromo-2'-deoxyguanosine (8-BrdG). The reaction of taurine with HOBr yielded taurine bromamine, which is the most stable among other bromamines of amino acids. Taurine also enhanced the bromination of only dG among the four 2'-deoxynucleosides, whereas it inhibited the 8-CldG formation. The specificity of taurine for the enhanced formation of halogenated dG is completely different from that of nicotine, an enhancer of chlorination. The amount of dibrominated taurine (taurine dibromamine) closely correlated with the formation of 8-BrdG, suggesting that taurine dibromamine might be a plausible mediator for the dG bromination in vivo. (C) 2015 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.abb.2015.10.002

Allyl isothiocyanate induces stomatal closure in Vicia faba Reviewed

Muhammad Abdus Sobahan, Nasima Akter, Eiji Okuma, Misugi Uraji, Wenxiu Ye, Izumi C. Mori, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 79 ( 10 ) 1737 - 1742 2015.10

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Isothiocyanates are enzymatically produced from glucosinolates in plants, and allyl isothiocyanate (AITC) induces stomatal closure in Arabidopsis thaliana. In this study, we investigated stomatal responses to AITC in Vicia faba. AITC-induced stomatal closure accompanied by reactive oxygen species (ROS) and NO production, cytosolic alkalization and glutathione (GSH) depletion in V. faba. GSH monoethyl ester induced stomatal reopening and suppressed AITC-induced GSH depletion in guard cells. Exogenous catalase and a peroxidase inhibitor, salicylhydroxamic acid, inhibited AITC-induced stomatal closure, unlike an NAD(P)H oxidase inhibitor, diphenylene iodonium chloride. The peroxidase inhibitor also abolished the AITC-induced ROS production, NO production, and cytosolic alkalization. AITC-induced stomatal closure was suppressed by an NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, and an agent to acidify cytosol, butyrate. These results indicate that AITC-induced stomatal closure in V. faba as well as in A. thaliana and suggest that AITC signaling in guard cells is conserved in both plants.

DOI： 10.1080/09168451.2015.1045827

Two guard cell mitogen-activated protein kinases, MPK9 and MPK12, function in methyl jasmonate-induced stomatal closure in Arabidopsis thaliana Reviewed

Md. A. R. Khokon, M. A. Salam, F. Jammes, W. Ye, M. A. Hossain, M. Uraji, Y. Nakamura, I. C. Mori, J. M. Kwak, Y. Murata

PLANT BIOLOGY 17 ( 5 ) 946 - 952 2015.9

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Methyl jasmonate (MeJA) and abscisic acid (ABA) signalling cascades share several signalling components in guard cells. We previously showed that two guard cell-preferential mitogen-activated protein kinases (MAPKs), MPK9 and MPK12, positively regulate ABA signalling in Arabidopsis thaliana. In this study, we examined whether these two MAP kinases function in MeJA signalling using genetic mutants for MPK9 and MPK12 combined with a pharmacological approach. MeJA induced stomatal closure in mpk9-1 and mpk12-1 single mutants as well as wild-type plants, but not in mpk9-1 mpk12-1 double mutants. Consistently, the MAPKK inhibitor PD98059 inhibited the MeJA-induced stomatal closure in wild-type plants. MeJA elicited reactive oxygen species (ROS) production and cytosolic alkalisation in guard cells of the mpk9-1, mpk12-1 and mpk9-1 mpk12-1 mutants, as well in wild-type plants. Furthermore, MeJA triggered elevation of cytosolic Ca2+ concentration ([Ca2+](cyt)) in the mpk9-1 mpk12-1 double mutant as well as wild-type plants. Activation of S-type anion channels by MeJA was impaired in mpk9-1 mpk12-1. Together, these results indicate that MPK9 and MPK12 function upstream of S-type anion channel activation and downstream of ROS production, cytosolic alkalisation and [Ca2+](cyt) elevation in guard cell MeJA signalling, suggesting that MPK9 and MPK12 are key regulators mediating both ABA and MeJA signalling in guard cells.

DOI： 10.1111/plb.12321

Open Stomata 1 Kinase is Essential for Yeast Elicitor-Induced Stomatal Closure in Arabidopsis Reviewed

Wenxiu Ye, Yuji Adachi, Shintaro Munemasa, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

PLANT AND CELL PHYSIOLOGY 56 ( 6 ) 1239 - 1248 2015.6

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

We recently demonstrated that yeast elicitor (YEL)-induced stomatal closure requires a Ca2+-dependent kinase, CPK6. A Ca2+-independent kinase, Open Stomata 1 (OST1), is involved in stomatal closure induced by various stimuli including ABA. In the present study, we investigated the role of OST1 in YEL-induced stomatal closure in Arabidopsis using a knock-out mutant, ost1-3, and a kinase-deficient mutant, ost1-2. YEL did not induce stomatal closure or activation of guard cell S-type anion channels in the ost1 mutants unlike in wild-type plants. However, YEL did not increase OST1 kinase activity in wild-type guard cells. The YEL-induced stomatal closure and activation of S-type anion channels were also impaired in a gain-of-function mutant of a clade A type 2C protein phosphatase (ABA INSENSITIVE 1), abi1-1C. In the ost1 mutants like in the wild type, YEL induced H2O2 accumulation, activation of non-selective Ca2+-permeable cation (I-Ca) channels and transient elevations in cytosolic free Ca2+ concentration ([Ca2+](cyt)) in guard cells. These results suggest that OST1 kinase is essential for stomatal closure and activation of S-type anion channels induced by YEL and that OST1 is not involved in H2O2 accumulation, I-Ca channel activation or [Ca2+](cyt) elevations in guard cells induced by YEL.

DOI： 10.1093/pcp/pcv051

Inhibition by acrolein of light-induced stomatal opening through inhibition of inward-rectifying potassium channels in Arabidopsis thaliana Reviewed

Md. Moshiul Islam, Wenxiu Ye, Daiki Matsushima, Md. Atiqur Rahman Khokon, Shintaro Munemasa, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 79 ( 1 ) 59 - 62 2015.1

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Acrolein is a reactive alpha,beta-unsaturated aldehyde derived from lipid peroxides, which are produced in plants under a variety of stress. We investigated effects of acrolein on light-induced stomatal opening using Arabidopsis thaliana. Acrolein inhibited light-induced stomatal opening in a dose-dependent manner. Acrolein at 100 mu M inhibited plasma membrane inward-rectifying potassium (K-in) channels in guard cells. Acrolein at 100 mu M inhibited K-in channel KAT1 expressed in a heterologous system using Xenopus leaves oocytes. These results suggest that acrolein inhibits light-induced stomatal opening through inhibition of K-in channels in guard cells.

DOI： 10.1080/09168451.2014.951028

Benzyl isothiocyanate inhibits IL-13 expression in human basophilic KU812 cells Reviewed

Yue Tang, Naomi Abe, Motoko Yoshimoto, Beiwei Zhu, Yoshiyuki Murata, Yoshimasa Nakamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 79 ( 1 ) 159 - 163 2015.1

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

An allergen-stimulating cytokine, interleukin-13 (IL-13), plays a significant role in allergic inflammation. Benzyl isothiocyanate (BITC), derived from several cruciferous vegetables, significantly suppressed the IL-13 expression in the calcium ionophore-stimulated human basophilic KU812 cells. Down-regulation of phosphorylated mitogen-activated protein kinases as well as nuclear transcriptional factors might be involved in the underlying mechanism.

DOI： 10.1080/09168451.2014.963503

Cyclic adenosine 5 '-diphosphoribose (cADPR) cyclic guanosine 3 ',5 '-monophosphate positively function in Ca2+ elevation in methyl jasmonate-induced stomatal closure, cADPR is required for methyl jasmonate-induced ROS accumulation NO production in guard cells Reviewed

M. A. Hossain, W. Ye, S. Munemasa, Y. Nakamura, I. C. Mori, Y. Murata

PLANT BIOLOGY 16 ( 6 ) 1140 - 1144 2014.11

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Methyl jasmonate (MeJA) signalling shares several signal components with abscisic acid (ABA) signalling in guard cells. Cyclic adenosine 5-diphosphoribose (cADPR) and cyclic guanosine 3,5-monophosphate (cGMP) are second messengers in ABA-induced stomatal closure. In order to clarify involvement of cADPR and cGMP in MeJA-induced stomatal closure in Arabidopsis thaliana (Col-0), we investigated effects of an inhibitor of cADPR synthesis, nicotinamide (NA), and an inhibitor of cGMP synthesis, LY83583 (LY, 6-anilino-5,8-quinolinedione), on MeJA-induced stomatal closure. Treatment with NA and LY inhibited MeJA-induced stomatal closure. NA inhibited MeJA-induced reactive oxygen species (ROS) accumulation and nitric oxide (NO) production in guard cells. NA and LY suppressed transient elevations elicited by MeJA in cytosolic free Ca2+ concentration ([Ca2+](cyt)) in guard cells. These results suggest that cADPR and cGMP positively function in [Ca2+](cyt) elevation in MeJA-induced stomatal closure, are signalling components shared with ABA-induced stomatal closure in Arabidopsis, and that cADPR is required for MeJA-induced ROS accumulation and NO production in Arabidopsis guard cells.

DOI： 10.1111/plb.12175

Tea Catechins Inhibit Cell Proliferation Through Hydrogen Peroxide-Dependent and -Independent Pathways in Human T lymphocytic Leukemia Jurkat Cells Reviewed

Yue Tang, Naomi Abe, Hang Qi, Beiwei Zhu, Yoshiyuki Murata, Yoshimasa Nakamura

FOOD SCIENCE AND TECHNOLOGY RESEARCH 20 ( 6 ) 1245 - 1249 2014.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：KARGER

In the present study, we investigated the anti-proliferative effects of four tea catechins: (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg) and (-)-epigallocatechin gallate (EGCg) in human T lymphocytic leukemia Jurkat cells. Each catechin induced a significant cytotoxic effect on Jurkat cells. Combinations of EGCg with other catechins additively potentiated anti-proliferation, extracellular hydrogen peroxide formation, c-Jun N-terminal kinase (JNK) activation and interferon (IFN)-gamma mRNA expression. Catalase partly but significantly abolished the cytotoxicity induced by EGC or EGCg, whereas it did not influence the EC- or ECg-induced effect. Among the tea catechins, ECg synergistically enhanced the EGCg-induced JNK phosphorylation and IFN-gamma expression. The present findings provide evidence that tea catechins are able to concertedly induce cytotoxicity through the JNK/IFN-gamma pathway in both a hydrogen peroxide-dependent and -independent manner.

DOI： 10.3136/fstr.20.1245

(-)-Epigallocatechin-3-Gallate Ameliorates Photodynamic Therapy Responses in an In Vitro T Lymphocyte Model Reviewed

Hang Qi, Naomi Abe, Beiwei Zhu, Yoshiyuki Murata, Yoshimasa Nakamura

PHYTOTHERAPY RESEARCH 28 ( 10 ) 1486 - 1491 2014.10

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

(-)-Epigallocatechin-3-gallate (EGCG), the most abundant polyphenolic constituent in green tea, is known as a powerful antioxidant but concomitantly possesses a prooxidant property. We investigated the effect of EGCG on phloxine B (PhB)-induced photocytotoxicity in human T lymphocytic leukemia Jurkat cells. EGCG significantly potentiated PhB-induced photocytotoxic effects, including the inhibition of cell proliferation, DNA fragmentation, and caspase-3 activity induction in Jurkat cells. Catalase attenuated the enhanced cytotoxicity by EGCG, suggesting the involvement of extracellularly produced hydrogen peroxide. Indeed, EGCG significantly enhanced extracellular hydrogen peroxide formation induced by photo-irradiated PhB. The EGCG also enhanced intracellular reactive oxygen species accumulation, c-Jun N-terminal kinase (JNK) phosphorylation, and interferon- (IFN-) gene expression, all of which are involved in PhB-induced apoptosis. Taken together, our data suggest that EGCG is capable of potentiating photodynamic therapy responses, presumably through the intracellular oxidative stress-sensitive JNK/IFN- pathway by exogenous hydrogen peroxide formation. Copyright (c) 2014 John Wiley & Sons, Ltd.

DOI： 10.1002/ptr.5152

Thiol modification by bioactivated polyphenols and its potential role in skin inflammation Reviewed

Yoshimasa Nakamura, Takeshi Ishii, Naomi Abe, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 78 ( 6 ) 1067 - 1070 2014.6

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

In the present study, we evaluated the modifying behavior of simple phenolic compounds on the sulfhydryl groups of glutathione and proteins. The catechol-type polyphenols, including protocatechuic acid, but neither the monophenols nor O-methylated catechol, can modify the sulfhydryl groups in a phenol oxidase-dependent manner. The possible involvement of polyphenol bioactivation in the enhancement of skin inflammation was also suggested.

DOI： 10.1080/09168451.2014.905190

Ascorbic Acid Synergistically Potentiates Phloxine B-induced Photocytotoxicity in Human Acute Promyelocytic Leukemia Cells Reviewed

Hang Qi, Qian Wu, Naomi Abe, Shunya Saiki, Beiwei Zhu, Yoshiyuki Murata, Yoshimasa Nakamura

JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY 28 ( 4 ) 167 - 173 2014.4

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Ascorbic acid (AsA) is known as an antioxidant but concomitantly possesses a pro-oxidant property. Because the impact of AsA on photodynamic therapy response is unclear, we investigated the effect of AsA on photocytotoxicity induced by phloxine B in human acute promyelocytic leukemia HL-60 cells. AsA synergistically enhanced phloxine B-induced photocytotoxic effects, including inhibition of cell proliferation, DNA ladder formation, and caspase-3 activation, whereas AsA itself showed no photocytotoxicity. AsA also enhanced the consumption of the reduced glutathione level compared with the cells treated with phloxine B alone under the light condition. Combination of AsA with phloxine B under the light condition enhanced the phosphorylation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase (MAPK). These effects were completely cancelled by catalase. These results suggest that AsA synergistically enhances phloxine B-induced photocytotoxicity, possibly through the extracellular oxidative stress-dependent MAPK pathway activation.

DOI： 10.1002/jbt.21549

Regulation of reactive oxygen species-mediated abscisic acid signaling in guard cells and drought tolerance by glutathione Reviewed

Shintaro Munemasa, Daichi Muroyama, Hiroki Nagahashi, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

Frontiers in Plant Science 4 2013.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Frontiers Research Foundation

The phytohormone abscisic acid (ABA) induces stomatal closure in response to drought stress, leading to reduction of transpirational water loss. A thiol tripeptide glutathione (GSH) is an important regulator of cellular redox homeostasis in plants. Although it has been shown that cellular redox state of guard cells controls ABA-mediated stomatal closure, roles of GSH in guard cell ABA signaling were largely unknown. Recently we demonstrated that GSH functions as a negative regulator of ABA signaling in guard cells. In this study we performed more detailed analyses to reveal how GSH regulates guard cell ABA signaling using the GSH-deficient Arabidopsis mutant cad2-1. The cad2-1 mutant exhibited reduced water loss from rosette leaves. Whole-cell current recording using patch clamp technique revealed that the cad2-1 mutation did not affect ABA regulation of S-type anion channels. We found enhanced activation of Ca2+ permeable channels by hydrogen peroxide (H2O2) in cad2-1 guard cells. The cad2-1 mutant showed enhanced H2O2-induced stomatal closure and significant increase of ROS accumulation in whole leaves in response to ABA. Our findings provide a new understanding of guard cell ABA signaling and a new strategy to improve plant drought tolerance. © 2013 Munemasa, Muroyama, Nagahashi, Nakamura, Mori and Murata.

DOI： 10.3389/fpls.2013.00472

Erratum: Role of protein tyrosine phosphatase 1B in vascular endothelial growth factor signaling and cell-cell adhesions in endothelial cells (Circulation Research (2008) 102 (1182-1191) DOI: 10.1161/ CIRCRESAHA.107. 167080) Reviewed

Y. Nakamura, N. Patrushev, H. Inomata, D. Mehta, N. Urao, H. W. Kim, M. Razvi, V. Kini, K. Mahadev, B. J. Goldstein, R. McKinney, T. Fukai, M. Ushi-Fukai

Circulation Research 113 2013.10

Calcium-dependent protein Kinase CPK6 positively functions in induction by yeast elicitor of stomatal closure and inhibition by yeast elicitor of light-induced stomatal opening in Arabidopsis Reviewed

Wenxiu Ye, Daichi Muroyama, Shintaro Munemasa, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

Plant Physiology 163 ( 2 ) 591 - 599 2013.10

Language：English Publishing type：Research paper (scientific journal)

Yeast elicitor (YEL) induces stomatal closure that is mediated by a Ca2+-dependent signaling pathway. A Ca2+-dependent protein kinase, CPK6, positively regulates activation of ion channels in abscisic acid and methyl jasmonate signaling, leading to stomatal closure in Arabidopsis (Arabidopsis thaliana). YEL also inhibits light-induced stomatal opening. However, it remains unknown whether CPK6 is involved in induction by YEL of stomatal closure or in inhibition by YEL of light-induced stomatal opening. In this study, we investigated the roles of CPK6 in induction by YEL of stomatal closure and inhibition by YEL of light-induced stomatal opening in Arabidopsis. Disruption of CPK6 gene impaired induction by YEL of stomatal closure and inhibition by YEL of light-induced stomatal opening. Activation by YEL of nonselective Ca2+-permeable cation channels was impaired in cpk6-2 guard cells, and transient elevations elicited by YEL in cytosolic-free Ca2+ concentration were suppressed in cpk6-2 and cpk6-1 guard cells. YEL activated slow anion channels in wild-type guard cells but not in cpk6-2 or cpk6-1 and inhibited inward-rectifying K+ channels in wild-type guard cells but not in cpk6-2 or cpk6-1. The cpk6-2 and cpk6-1 mutations inhibited YEL-induced hydrogen peroxide accumulation in guard cells and apoplast of rosette leaves but did not affect YEL-induced hydrogen peroxide production in the apoplast of rosette leaves. These results suggest that CPK6 positively functions in induction by YEL of stomatal closure and inhibition by YEL of light-induced stomatal opening in Arabidopsis and is a convergent point of signaling pathways for stomatal closure in response to abiotic and biotic stress. © 2013 American Society of Plant Biologists. All Rights Reserved.

DOI： 10.1104/pp.113.224055

Difference in Abscisic Acid Perception Mechanisms between Closure Induction and Opening Inhibition of Stomata Reviewed

Ye Yin, Yuji Adachi, Wenxiu Ye, Maki Hayashi, Yoshimasa Nakamura, Toshinori Kinoshita, Izumi C. Mori, Yoshiyuki Murata

PLANT PHYSIOLOGY 163 ( 2 ) 600 - 610 2013.10

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC PLANT BIOLOGISTS

Abscisic acid (ABA) induces stomatal closure and inhibits light-induced stomatal opening. The mechanisms in these two processes are not necessarily the same. It has been postulated that the ABA receptors involved in opening inhibition are different from those involved in closure induction. Here, we provide evidence that four recently identified ABA receptors (PYRABACTIN RESISTANCE1 [PYR1], PYRABACTIN RESISTANCE-LIKE1 [PYL1], PYL2, and PYL4) are not sufficient for opening inhibition in Arabidopsis (Arabidopsis thaliana). ABA-induced stomatal closure was impaired in the pyr1/pyl1/pyl2/pyl4 quadruple ABA receptor mutant. ABA inhibition of the opening of the mutant's stomata remained intact. ABA did not induce either the production of reactive oxygen species and nitric oxide or the alkalization of the cytosol in the quadruple mutant, in accordance with the closure phenotype. Whole cell patch-clamp analysis of inward-rectifying K+ current in guard cells showed a partial inhibition by ABA, indicating that the ABA sensitivity of the mutant was not fully impaired. ABA substantially inhibited blue light-induced phosphorylation of H+-ATPase in guard cells in both the mutant and the wild type. On the other hand, in a knockout mutant of the SNF1-related protein kinase, srk2e, stomatal opening and closure, reactive oxygen species and nitric oxide production, cytosolic alkalization, inward-rectifying K+ current inactivation, and H+-ATPase phosphorylation were not sensitive to ABA.

DOI： 10.1104/pp.113.223826

Endogenous abscisic acid is involved in methyl jasmonate-induced reactive oxygen species and nitric oxide production but not in cytosolic alkalization in Arabidopsis guard cells Reviewed

Wenxiu Ye, Mohammad Anowar Hossain, Shintaro Munemasa, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 170 ( 13 ) 1212 - 1215 2013.9

Language：English Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

We recently demonstrated that endogenous abscisic acid (ABA) is involved in methyl jasmonate (MeJA)induced stomatal closure in Arabidopsis thaliana. In this study, we investigated whether endogenous ABA is involved in MeJA-induced reactive oxygen species (ROS) and nitric oxide (NO) production and cytosolic alkalization in guard cells using an ABA-deficient Arabidopsis mutant, aba2-2, and an inhibitor of ABA biosynthesis, fiuridon (FLU). The aba2-2 mutation impaired MeJA-induced ROS and NO production. FLU inhibited MeJA-induced ROS production in wild-type guard cells. Pretreatment with 0.1 mu M ABA, which does not induce stomatal closure in the wild type, complemented the insensitivity to MeJA of the aba2-2 mutant. However, MeJA induced cytosolic alkalization in both wild-type and aba2-2 guard cells. These results suggest that endogenous ABA is involved in MeJA-induced ROS and NO production but not in MeJA-induced cytosolic alkalization in Arabidopsis guard cells. (C) 2013 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.jplph.2013.03.011

Catalases CAT1 and CAT3 Are not Key Enzymes in Alleviating Gamma Irradiation-Induced DNA Damage, H2O2 Accumulation, or Lipid Peroxidation in Arabidopsis thaliana Reviewed

Amena Sultana, Ikuko Minami, Daiki Matsushima, Mohammad Issak, Yoshimasa Nakamura, Setsuko Todoriki, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 77 ( 9 ) 1984 - 1987 2013.9

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Gamma irradiation increased catalase activities at 0.1 kGy and decreased them at 10 kGy in Arabidopsis wild type and catalase-deficient mutants, cat3-1 and cat1 cat3. Irradiation induced DNA damage, H2O2 accumulation, and lipid peroxidation in both mutants as well as the wild type. Thus catalases might not be key enzymes protecting gamma irradiation-induced damage.

DOI： 10.1271/bbb.130336

Lower Photostability of Capsanthin Dispersed in an Aqueous Solution Reviewed

Masayuki Nishino, Makoto Sakata, Yoshiyuki Murata, Yoshimasa Nakamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 77 ( 6 ) 1313 - 1316 2013.6

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Food-additive grades of capsanthin, lutein, lycopene, and beta-carotene dispersed in aqueous solutions were photo-irradiated using a Xenon weather meter, and the levels of carotenoids were measured by HPLC and the absorbance method. Capsanthin photo-degraded more rapidly than the carotenoids tested, with less oxygen consumption. Unlike carotenes, capsanthin was partially converted into analogous colored compounds during degradation.

DOI： 10.1271/bbb.130033

Neither Endogenous Abscisic Acid nor Endogenous Jasmonate Is Involved in Salicylic Acid-, Yeast Elicitor-, or Chitosan-Induced Stomatal Closure in Arabidopsis thaliana Reviewed

Mohammad Issak, Eiji Okuma, Shintaro Munemasa, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 77 ( 5 ) 1111 - 1113 2013.5

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Salicylic acid (SA), yeast elicitor (YEL), and chitosan (CHT) induced stomatal closure in Arabidopsis wildtype and aba2-2 plants, induced stomatal closure in fluridon-treated wild-type plants, and induced stomatal closure in aos mutants. These results suggest that neither endogenous abscisic acid nor endogenous jasmonic acid is involved in SA-, YEL-, or CHT-induced stomatal closure.

DOI： 10.1271/bbb.120980

Two guard cell-preferential MAPKs, MPK9 and MPK12, regulate YEL signalling in Arabidopsis guard cells Reviewed

M. A. Salam, F. Jammes, M. A. Hossain, W. Ye, Y. Nakamura, I. C. Mori, J. M. Kwak, Y. Murata

Plant Biology 15 ( 3 ) 436 - 442 2013.5

Language：English Publishing type：Research paper (scientific journal)

We report that two mitogen-activated protein kinases (MAPKs), MPK9 and MPK12, positively regulate abscisic acid (ABA)-induced stomatal closure in Arabidopsis thaliana. Yeast elicitor (YEL) induced stomatal closure accompanied by intracellular reactive oxygen species (ROS) accumulation and cytosolic free calcium concentration ([Ca2+]cyt) oscillation. In this study, we examined whether these two MAP kinases are involved in YEL-induced stomatal closure using MAPKK inhibitors, PD98059 and U0126, and MAPK mutants, mpk9, mpk12 and mpk9 mpk12. Both PD98059 and U0126 inhibited YEL-induced stomatal closure. YEL induced stomatal closure in the mpk9 and mpk12 mutants but not in the mpk9 mpk12 mutant, suggesting that a MAPK cascade involving MPK9 and MPK12 functions in guard cell YEL signalling. However, YEL induced extracellular ROS production, intracellular ROS accumulation and cytosolic alkalisation in the mpk9, mpk12 and mpk9 mpk12 mutants. YEL induced [Ca2+]cyt oscillations in both wild type and mpk9 mpk12 mutant. These results suggest that MPK9 and MPK12 function redundantly downstream of extracellular ROS production, intracellular ROS accumulation, cytosolic alkalisation and [Ca2+]cyt oscillation in YEL-induced stomatal closure in Arabidopsis guard cells and are shared with ABA signalling. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

DOI： 10.1111/j.1438-8677.2012.00671.x

Negative Regulation of Methyl Jasmonate-Induced Stomatal Closure by Glutathione in Arabidopsis Reviewed

Nasima Akter, Eiji Okuma, Muhammad Abdus Sobahan, Misugi Uraji, Shintaro Munemasa, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

JOURNAL OF PLANT GROWTH REGULATION 32 ( 1 ) 208 - 215 2013.3

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Glutathione (GSH) has been shown to negatively regulate methyl jasmonate (MeJA)-induced stomatal closure. We investigated the roles of GSH in MeJA signaling in guard cells using an Arabidopsis mutant, cad2-1, that is deficient in the first GSH biosynthesis enzyme, gamma-glutamylcysteine synthetase. MeJA-induced stomatal closure and decreased GSH contents in guard cells. Decreasing GSH by the cad2-1 mutation enhanced MeJA-induced stomatal closure. Depletion of GSH by the cad2-1 mutation or increment of GSH by GSH monoethyl ester did not affect either MeJA-induced production of reactive oxygen species (ROS) or MeJA-induced cytosolic alkalization in guard cells. MeJA and abscisic acid (ABA) induced stomatal closure and GSH depletion in atrbohD and atrbohF single mutants but not in the atrbohD atrbohF double mutant. Moreover, exogenous hydrogen peroxide induced stomatal closure but did not deplete GSH in guard cells. These results indicate that GSH affects MeJA signaling as well as ABA signaling and that GSH negatively regulates a signal component other than ROS production and cytosolic alkalization in MeJA signal pathway of Arabidopsis guard cells.

DOI： 10.1007/s00344-012-9291-7

Effects of emulsifiers on the photostability of lycopene Reviewed

Masayuki Nishino, Makoto Sakata, Yoshiyuki Murata, Yoshimasa Nakamura

Food Science and Technology Research 19 ( 6 ) 983 - 987 2013

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

Aqueous solutions of dispersed lycopene in which gum arabic, gum ghatti and polyglycerol monostearate ester had been used as emulsifiers were photoirradiated. The photodegradation rate of lycopene tended to vary depending on the amount of polyglycerol monostearate ester used. We found that the photodegradation rate of lycopene with polyglycerol monostearate ester was considerably slower than those with gum arabic and gum ghatti. Therefore, this study suggests that the absorption state of the emulsifier on the crystal surface may affect the photodegradation rate of lycopene.

DOI： 10.3136/fstr.19.983

Catalase, CAT2, is not Involved in Mitigation of Gamma Irradiation-induced H₂O₂ Accumulation or Lipid Peroxidation in Arabidopsis thaliana Reviewed

Sultana Amena, Minami Ikuko, Matsushima Daiki, Issak Mohammad, Nakamura Yoshimasa, Todoriki Setsuko, Murata Yoshiyuki

FOOD IRRADIATION, JAPAN 48 ( 1 ) 38 - 41 2013

Language：Japanese Publisher：日本食品照射研究協議会

In Arabidopsis wild-type (Col-0 ecotype) and <i>cat2</i> mutant plants, gamma radiation induced H<sub>2</sub>O<sub>2</sub> accumulation and lipid peroxidation at 10 kGy but not at 0.1 to 1 kGy. There were no significant differences in H<sub>2</sub>O<sub>2</sub> accumulation and lipid peroxidation between the wild type and the <i>cat2</i> mutant. Hence, CAT2 may not be a key enzyme to protect gamma irradiation-induced damage.

DOI： 10.5986/jrafi.48.38

Glucosinolate degradation products, isothiocyanates, nitriles, and thiocyanates, induce stomatal closure accompanied by peroxidase-mediated reactive oxygen species production in arabidopsis thaliana Reviewed

Mohammad Shakhawat Hossain, Wenxiu Ye, Mohammad Anowar Hossain, Eiji Okuma, Misugi Uraji, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

Bioscience, Biotechnology and Biochemistry 77 ( 5 ) 977 - 983 2013

Language：English Publishing type：Research paper (scientific journal)

Isothiocyanates, nitriles, and thiocyanates are degradation products of glucosinolates in crucifer plants. In this study, we investigated the stomatal response to allyl isothiocyanate (AITC), 3-butenenitrile (3BN), and ethyl thiocyanate (ESCN) in Arabidopsis. AITC, 3BN, and ESCN induced stomatal closure in the wild type and the atrbohD atrbohF mutant. Stomatal closure was inhibited by catalase and salicylhydroxamic acid (SHAM). The degradation products induced extracellular reactive oxygen species (ROS) production in the rosette leaves, and intracellular ROS accumulation, NO production, and cytosolic free calcium concentration ([Ca2+]cyt) oscillations in guard cells, which were inhibited by SHAM. These results suggest that glucosinolate degradation products induce stomatal closure accompanied by extracellular ROS production mediated by SHAMsensitive peroxidases, intracellular ROS accumulation, and [Ca 2+]cyt oscillation in Arabidopsis.

DOI： 10.1271/bbb.120928

Effects of γ-Irradiation on Larval and Adult Stages of Tribolium castaneum (Red Flour Beetle) Reviewed

Sultana Amena, Minami Ikuko, Ichiba Ryuji, Issak Mohammad, Tada Mikiro, Nakamura Yoshimasa, Miyatake Takahisa, Todoriki Setsuko, Murata Yoshiyuki

FOOD IRRADIATION, JAPAN 48 ( 1 ) 19 - 23 2013

Language：Japanese Publisher：日本食品照射研究協議会

Food irradiation using γ-rays is one of powerful tools to reduce insect infestation in crops and spices. We examined the effects of γ-irradiation on larvae and adults of <i>Tribolium castaneum</i>. Eclosion for larvae was completely inhibited by irradiation at 500 Gy. A survival rate for adults was markedly reduced by irradiation at more than 500 Gy. The neutral comet assay presented that irradiation irreversibly increased DNA damage at 500 and 1000 Gy and transiently increased DNA damage at 100 Gy, suggesting possible DNA repair in larvae and adults stages. These results indicate that γ-irradiation at 500 Gy is available to eradicate the beetle at larval and adults stages.

DOI： 10.5986/jrafi.48.19

Effects of Depletion of Glutathione on Abscisic Acid- and Methyl Jasmonate-Induced Stomatal Closure in Arabidopsis thaliana Reviewed

Nasima Akter, Muhammad Abdus Sobahan, Misugi Uraji, Wenxiu Ye, Mohammad Anowar Hossain, Izumi C. Mori, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 76 ( 11 ) 2032 - 2037 2012.11

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Glutathione (GSH) is involved in abscisic acid (ABA)-and methyl jasmonate (MeJA)-induced stomatal closure in Arabidopsis thaliana. In this study, we examined the effects of GSH-decreasing chemicals, p-nitrobenzyl chloride (PNBC), iodomethane (IDM), and ethacrynic acid (EA), on ABA- and MeJA-induced stomatal closure in Arabidopsis. Treatments with PNBC, IDM, and EA decreased GSH contents in guard cells. Depletion of GSH by PNBC and IDM enhanced ABA- and MeJA-induced stomatal closure and inhibition of light-induced stomatal opening by ABA, whereas EA did not enhance either ABA- and MeJA-induced stomatal closure or inhibition of light-induced stomatal opening by ABA. Depletion of GSH did not significantly increase the production of the reactive oxygen species (ROS), cytosolic alkalization, or cytosolic Ca2+ oscillation induced by ABA and MeJA. These results indicate that depletion of GSH enhances ABA- and MeJA-induced stomatal closure without affecting ROS production, cytosolic alkalization, or cytosolic Ca2+ oscillation in guard cells of Arabidopsis.

DOI： 10.1271/bbb.120384

Development and application of a method for identification of isothiocyanate-targeted molecules in colon cancer cells. Reviewed International journal

Noriyuki Miyoshi, Takumi Yonemochi, Susumu Tomono, Ryuuta Fukutomi, Yoshimasa Nakamura, Hiroshi Ohshima

Analytical biochemistry 429 ( 2 ) 124 - 31 2012.10

Language：English

In this study, we have developed a novel method to identify isothiocyanate (ITC)-targeted molecules using two well-studied ITCs: benzyl ITC (BITC) and phenethyl ITC (PEITC). The principle of this method is based on identifying a pattern of differences between BITC and PEITC given that they show similar chemical and biological behaviors. For method validation, dithiothreitol-reduced bovine insulin as a model molecule was incubated with either BITC or PEITC, and digested peptides were analyzed by ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) and liquid chromatography quadrupole TOF-MS (LC-Q-TOF-MS). Three peptides-NYCN, FVNQHLCGSHLVE, and ALYLVCGE-were identified as being adducted with BITC or PEITC on their cysteine residues. Each set of peptides adducted with either BITC or PEITC showed retention times (RT(BITC)<RT(PEITC)) by reverse-phase column chromatography with a difference of molecular mass (Δ14.01565). On the basis of these findings, computational mathematical schemes were constructed to extract sets of MS ions satisfying the above criteria. Application of the developed method to an extract of ITC-treated human colon cancer HCT116 cells, thiocarbamoylation of cysteine residues of glutathione, and the N-terminal proline residues of PMFIVNTNVPR from macrophage migration inhibitory factor were successfully identified as one of the intracellular targets of ITCs. Moreover, the method also detected the thiocarbamoylated conjugates of ITCs with intracellular free cysteines and lysines.

DOI： 10.1016/j.ab.2012.07.018

Methylglyoxal inhibits seed germination and root elongation and up-regulates transcription of stress-responsive genes in ABA-dependent pathway in Arabidopsis Reviewed

T. S. Hoque, M. Uraji, A. Tuya, Y. Nakamura, Y. Murata

PLANT BIOLOGY 14 ( 5 ) 854 - 858 2012.9

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Methylglyoxal (MG) is a highly reactive metabolite derived from glycolysis. In this study, we examined the effect of MG on seed germination, root elongation, chlorosis and stress-responsive gene expression in Arabidopsis using an abscisic acid (ABA)-deficient mutant, aba2-2. In the wild type, 0.1 mm MG did not affect germination but delayed root elongation, whereas 1.0 mm MG inhibited germination and root elongation and induced chlorosis. MG increased transcription levels of RD29B and RAB18 in a dose-dependent manner but did not affect RD29A transcription level. In contrast, in the aba2-2 mutant, MG inhibition of seed germination at 1.0 mm and 10.0 mm and a delay of root elongation at 0.1 mm MG were mitigated, although there was no significant difference in chlorosis between the wild type and mutant. Moreover, the aba2-2 mutation impaired MG-induced RD29B and RAB18 gene expression. These observations suggest that MG not only directly inhibits germination and root elongation but also indirectly modulates these processes via endogenous ABA in Arabidopsis.

DOI： 10.1111/j.1438-8677.2012.00607.x

MAP Kinases, MPK9 and MPK12, Regulate Chitosan-Induced Stomatal Closure Reviewed

Mohammad Abdus Salam, Fabien Jammes, Mohammad Anowar Hossain, Wenxiu Ye, Yoshimasa Nakamura, Izumi C. Mori, June M. Kwak, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 76 ( 9 ) 1785 - 1787 2012.9

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Chitosan (CHT)-induced stomatal closure was inhibited by an MAPKK inhibitor, PD98059, and was impaired in mpk9 mpk12 but not in mpk9 or mpk12. CHT induced the production of reactive oxygen species, cytosolic alkalization, and cytosolic Ca2+ oscillation in mpk9 mpk12. These results suggest that MPK9 and MPK12 are involved in CHT-induced stomatal closure.

DOI： 10.1271/bbb.120228

Effects of Exogenous Proline and Glycinebetaine on the Salt Tolerance of Rice Cultivars Reviewed

Muhammad Abdus Sobahan, Nasima Akter, Misao Ohno, Eiji Okuma, Yoshihiko Hirai, Izumi C. Mori, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 76 ( 8 ) 1568 - 1570 2012.8

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Salinity significantly increased trisodium-8-hydroxy-1,3,6-pyrenetrisulphonic acid (PTS) uptake and decreased the K+/Na+ ratio in salt-sensitive rice (Nipponbare) but did not markedly in salt-tolerant rice (Pokkali). Proline and glycinebetaine (betaine) suppressed the increase in PTS uptake and the decrease in the K+/Na+ ratio in Nipponbare, but did not affect PTS uptake or the K+/Na+ ratio in Pokkali.

DOI： 10.1271/bbb.120233

Methylglyoxal inhibition of cytosolic ascorbate peroxidase from Nicotiana tabacum Reviewed

Md. Anamul Hoque, Misugi Uraji, Akiko Torii, Mst. Nasrin Akhter Banu, Izumi C. Mori, Yoshimasa Nakamura, Yoshiyuki Murata

JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY 26 ( 8 ) 315 - 321 2012.8

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Methylglyoxal (MG) is one of the aldehydes accumulated in plants under environmental stress. Cytosolic ascorbate peroxidase (cAPX) plays a key role in the protection of cells from oxidative damage by scavenging reactive oxygen species in higher plants. A cDNA encoding cAPX, named NtcAPX, was isolated from Nicotiana tabacum. We characterized recombinant NtcAPX (rNtcAPX) as a fusion protein with glutathione S-transferase to investigate the effects of MG on APX. NtcAPX consists of 250 amino acids and has a deduced molecular mass of 27.5 kDa. The rNtcAPX showed a higher APX activity. MG treatments resulted in a reduction of APX activity and modifications of amino groups in rNtcAPX with increasing Km for ascorbate. On the contrary, neither NaCl nor cadmium reduced the activity of APX. The present study suggests that inhibition of APX is in part due to the modification of amino acids by MG. (c) 2012 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26:315321, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.21423

DOI： 10.1002/jbt.21423

Catalases negatively regulate methyl jasrnonate signaling in guard cells Reviewed

Rayhanur Jannat, Misugi Uraji, Mohammad Anowar Hossain, Mohammad Muzahidul Islam, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 169 ( 10 ) 1012 - 1016 2012.7

Language：English Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

Methyl jasmonate (MeJA)-induced stomatal closure is accompanied by the accumulation of hydrogen peroxide (H2O2) in guard cells. In this study, we investigated the roles of catalases (CATs) in MeJA-induced stomatal closure using cat mutants cat2, cat3-1 and cat1 cat3, and the CAT inhibitor, 3-aminotriazole (AT). When assessed with 2',7'-dichlorodihydrofluorescein, the reduction of catalase activity by means of mutations and the inhibitor accumulated higher basal levels of H2O2 in guard cells whereas they did not affect stomatal aperture in the absence of MeJA. In contrast, the cat mutations and the treatment with AT potentiated MeJA-induced stomatal closure and MeJA-induced H2O2 production. These results indicate that CATs negatively regulate H2O2 accumulation in guard cells and suggest that inducible H2O2 production rather than constitutive elevation modulates stomatal apertures in Arabidopsis. (C) 2012 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.jplph.2012.03.006

Hydogen peroxide-dependent photocytotoxicity by phloxine B, a xanthene-type food colorant (vol 1810, pg 704, 2011) Reviewed

Hang Qi, Hiroshi Takano, Yoji Kato, Qian Wu, Chiharu Ogata, Beiwei Zhu, Yoshiyuki Murata, Yoshimasa Nakamura

BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS 1820 ( 7 ) 1020 - 1020 2012.7

Methylglyoxal-induced stomatal closure accompanied by peroxidase-mediated ROS production in Arabidopsis Reviewed

Tahsina Sharmin Hoque, Misugi Uraji, Wenxiu Ye, Mohammad Anowar Hossain, Yoshimasa Nakamura, Yoshiyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 169 ( 10 ) 979 - 986 2012.7

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

Methylglyoxal (MG) is an oxygenated short aldehyde and a glycolytic intermediate that accumulates in plants under environmental stresses. Being a reactive alpha-oxoaldehyde, MG may act as a signaling molecule in plants during stresses. We investigated whether MG induces stomatal closure, reactive oxygen species (ROS) production, and cytosolic free calcium concentration ([Ca2+](cyt)) to clarify roles of MG in Arabidopsis guard cells. MG induced production of ROS and [Ca2+](cyt) oscillations, leading to stomatal closure. The MG-induced stomatal closure and ROS production were completely inhibited by a peroxidase inhibitor, salicylhydroxamic acid (SHAM), but were not affected by an NAD(P)H oxidase mutation, atrbohD atrbohF. Furthermore, the MG-elicited [Ca2+](cyt), oscillations were significantly suppressed by SHAM but not by the atrbohD atrbohF mutation. Neither endogenous abscisic acid nor endogenous methyl jasmonate was involved in MG-induced stomatal closure. These results suggest that intrinsic metabolite MG can induce stomatal closure in Arabidopsis accompanied by extracellular ROS production mediated by SHAM-sensitive peroxidases, intracellular ROS accumulation, and [Ca2+](cyt) oscillations. (C) 2012 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.jplph.2012.02.007

Involvement of intracellular oxidative stress-sensitive pathway in phloxine B-induced photocytotoxicity in human T lymphocytic leukemia cells Reviewed

Hang Qi, Beiwei Zhu, Naomi Abe, Yuko Shin, Yoshiyuki Murata, Yoshimasa Nakamura

FOOD AND CHEMICAL TOXICOLOGY 50 ( 6 ) 1841 - 1847 2012.6

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

We investigated the molecular mechanisms underlying phloxine B (PhB)-induced photocytotoxicity in human T lymphocytic leukemia Jurkat cells. In addition to apoptosis-related biochemical events, photo-irradiated PhB generated intracellular reactive oxygen species (ROS), induced phosphorylation of c-Jun-N-terminal kinase (JNK) in an oxidative stress-dependent manner and up-regulated the gene expression of interferon (IFN)-gamma, an inducer of diverse apoptosis-related molecules in activated T cells. PhB-induced apoptosis was significantly inhibited by N-acetyl-l-cysteine, but not by catalase, indicating that ROS generation occurred intracellularly, and by SP600125 and AG490, specific inhibitors of JNK and IFN-gamma signaling, respectively, confirming their roles in the apoptotic pathway. IFN-gamma up-regulation was also inhibited by SP600125, indicating that it was downstream of INK activation. These results suggest that PhB-induced apoptosis in Jurkat cells partially involves the intracellular oxidative stress-sensitive and T cell-specific IFN-gamma pathway. These data present a novel insight into the mechanisms of photocytotoxicity induced by artificial food colorants in human T lymphocytic leukemia cells. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.fct.2012.03.011

Mechanisms of the Selenium Tolerance of the Arabidopsis thaliana Knockout Mutant of Sulfate Transporter SULTR1;2 Reviewed

Misao Ohno, Misugi Uraji, Yasuaki Shimoishi, Izumi C. Mori, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 76 ( 5 ) 993 - 998 2012.5

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

We investigated the mechanism of selenium (Se) tolerance using an Arabidopsis thaliana knockout mutant of a sulfate transporter, sultr1;2. Se stress inhibited plant growth, decreased chlorophyll contents, and increased protein oxidation and lipid peroxidation in the wild type, whereas the sultr1;2 mutation mitigated damage of these forms, indicating that sultr1;2 is more tolerant of Se than the wild type is. The accumulation of symplastic Se was suppressed in sultr1;2 as compared to the wild type, and the chemical speciation of Se in the mutant was different from that in the wild type. Regardless of Se stress, the activities of ascorbate peroxidase, catalase, and peroxidase in the mutant were higher than in the wild type, while the activity of superoxide dismutase in the mutant was the same as in the wild type. These results suggest that the sultr1;2 mutation confers Se tolerance on Arabidopsis by decreasing symplastic Se and maintaining antioxidant enzyme activities.

DOI： 10.1271/bbb.111000

Effect of gamma Irradiation on the Fatty Acid Composition of Soybean and Soybean Oil Reviewed

Ikuko Minami, Yoshimasa Nakamura, Setsuko Todoriki, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 76 ( 5 ) 900 - 905 2012.5

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Food irradiation is a form of food processing to extend the shelf life and reduce spoilage of food. We examined the effects of gamma radiation on the fatty acid composition, lipid peroxidation level, and antioxidative activity of soybean and soybean oil which both contain a large amount of unsaturated fatty acids. Irradiation at 10 to 80 kGy under aerobic conditions did not markedly change the fatty acid composition of soybean. While 10-kGy irradiation did not markedly affect the fatty acid composition of soybean oil under either aerobic or anaerobic conditions, 40-kGy irradiation considerably altered the fatty acid composition of soybean oil under aerobic conditions, but not under anaerobic conditions. Moreover, 40-kGy irradiation produced a significant amount of trans fatty acids under aerobic conditions, but not under anaerobic conditions. Irradiating soybean oil induced lipid peroxidation and reduced the radical scavenging activity under aerobic conditions, but had no effect under anaerobic conditions. These results indicate that the fatty acid composition of soybean was not markedly affected by radiation at 10 kGy, and that anaerobic conditions reduced the degradation of soybean oil that occurred with high doses of gamma radiation.

DOI： 10.1271/bbb.110859

Cooperative Function of PLD delta and PLD alpha 1 in Abscisic Acid-Induced Stomatal Closure in Arabidopsis Reviewed

Misugi Uraji, Takeshi Katagiri, Eiji Okuma, Wenxiu Ye, Mohammad Anowar Hossain, Choji Masuda, Aya Miura, Yoshimasa Nakamura, Izumi C. Mori, Kazuo Shinozaki, Yoshiyuki Murata

PLANT PHYSIOLOGY 159 ( 1 ) 450 - 460 2012.5

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC PLANT BIOLOGISTS

Phospholipase D (PLD) is involved in responses to abiotic stress and abscisic acid (ABA) signaling. To investigate the roles of two Arabidopsis (Arabidopsis thaliana) PLDs, PLD alpha 1 and PLD delta, in ABA signaling in guard cells, we analyzed ABA responses in guard cells using Arabidopsis wild type, pld alpha 1 and pld delta single mutants, and a pld alpha 1 pld delta double mutant. ABA-induced stomatal closure was suppressed in the pld alpha 1 pld delta double mutant but not in the pld single mutants. The pld alpha 1 and pld delta mutations reduced ABA-induced phosphatidic acid production in epidermal tissues. Expression of either PLD alpha 1 or PLD delta complemented the double mutant stomatal phenotype. ABA-induced stomatal closure in both pld alpha 1 and pld delta single mutants was inhibited by a PLD inhibitor (1-butanol), suggesting that both PLD alpha 1 and PLD delta function in ABA-induced stomatal closure. During ABA-induced stomatal closure, wild-type guard cells accumulate reactive oxygen species and nitric oxide and undergo cytosolic alkalization, but these changes are reduced in guard cells of the pld alpha 1 pld delta double mutant. Inward-rectifying K+ channel currents of guard cells were inhibited by ABA in the wild type but not in the pld alpha 1 pld delta double mutant. ABA inhibited stomatal opening in the wild type and the pld delta mutant but not in the pld alpha 1 mutant. In wild-type rosette leaves, ABA significantly increased PLD delta transcript levels but did not change PLD alpha 1 transcript levels. Furthermore, the pld alpha 1 and pld delta mutations mitigated ABA inhibition of seed germination. These results suggest that PLD alpha 1 and PLD delta cooperate in ABA signaling in guard cells but that their functions do not completely overlap.

DOI： 10.1104/pp.112.195578

Luteolin Overcomes Resistance to Benzyl Isothiocyanate-Induced Apoptosis in Human Colorectal Cancer HCT-116 Cells Invited Reviewed

Rieko Sakai, Shintaro Yokobe, Naomi Abe, Noriyuki Miyoshi, Yoshiyuki Murata, Yoshimasa Nakamura

JOURNAL OF FOOD AND DRUG ANALYSIS 20 389 - 393 2012.4

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：FOOD & DRUG ADMINSTRATION

We have previously identified p53, a universal sensor of genotoxic stress, as a negative regulator of the apoptosis induction by benzyl isothiocyanate (BITC) in the normal colon fibroblastoid cells. In the present study, we further confirmed that BITC has a potential to induce cytotoxicity in the p53-mutated colon cancer HT-29 cells in preference to HCT-116 cells with wild-type p53. To obtain effective induction of BITC-stimulated apoptosis in p53-positive cells, we investigated the combination effect of BITC and food ingredient that may overcome resistance to BITC. Pretreatment with luteolin potentiated the cytotoxicity induction by BITC in HCT-116 cells but not in HT-29 cells. The biochemical events related to apoptosis such as DNA ladder formation and caspase-3 activation were also enhanced by luteolin. Luteolin attenuated the expression of p21(wafl/cipl) a key downstream target of p53. These results suggest the role of p21(wafl/cipl) pathway in the overcoming BITC resistance by luteolin.

Increased halogenated tyrosine levels are useful markers of human skin ageing, reflecting proteins denatured by past skin inflammation Reviewed

Y. Ishitsuka, F. Maniwa, C. Koide, Y. Kato, Y. Nakamura, T. Osawa, M. Tanioka, Y. Miyachi

CLINICAL AND EXPERIMENTAL DERMATOLOGY 37 ( 3 ) 252 - 258 2012.4

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Background. Photoageing of skin is thought to be caused by protein denaturation, which can be induced by ultraviolet radiation. Previous studies have also reported that inflammation is related to protein denaturation; however, the influence of inflammation on skin ageing has not been explored in detail.
Aim. To investigate the possible connection between inflammation and protein denaturation, which might lead to skin ageing, we focused on halogenated tyrosine as a denatured substance produced during the inflammation process.
Methods. We measured halogenated tyrosine in aged human skin. Inflammatory cells and halogenated tyrosine were detected by immunohistochemistry using antibodies to mast-cell tryptase, neutrophilic myeloperoxidase and halogenated tyrosine. Finally, using elastic van Gieson ( EVG) staining, we investigated whether the sites of halogenated tyrosine coincided with the sites at which proteins were denatured.
Results. Immunohistochemical analysis indicated that both inflammatory cells and halogenated tyrosines increased with ageing in both photoexposed and photoprotected skin. EVG staining confirmed that the localization of halogenated tyrosine was close to the sites at which protein was denatured.
Conclusions. Our investigations indicate a possible connection between skin ageing and inflammation, suggesting that halogenated tyrosine could be a useful marker of ageing skin.

DOI： 10.1111/j.1365-2230.2011.04215.x

Inhibitory Effects of Methylglyoxal on Light-Induced Stomatal Opening and Inward K+ Channel Activity in Arabidopsis Reviewed

Tahsina Sharmin Hoque, Eiji Okuma, Misugi Uraji, Takuya Furuichi, Takayuki Sasaki, Md Anamul Hoque, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 76 ( 3 ) 617 - 619 2012.3

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Methylglyoxal (MG) is a reactive aldehyde derived by glycolysis. In Arabidopsis, MG inhibited light-induced stomatal opening in a dose-dependent manner. It significantly inhibited both inward-rectifying potassium (K-in) channels in guard-cell protoplasts and an Arabidopsis K-in channel, KAT1, heterologously expressed in Xenopus oocytes. Thus it appears that MG inhibition of stomatal opening involves MG inhibition of K+ influx into guard cells.

DOI： 10.1271/bbb.110885

FIA functions as an early signal component of abscisic acid signal cascade in Vicia faba guard cells Reviewed

Yusuke Sugiyama, Misugi Uraji, Megumi Watanabe-Sugimoto, Eiji Okuma, Shintaro Munemasa, Yasuaki Shimoishi, Yoshimasa Nakamura, Izumi C. Mori, Sumio Iwai, Yoshiyuki Murata

JOURNAL OF EXPERIMENTAL BOTANY 63 ( 3 ) 1357 - 1365 2012.2

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

An abscisic acid (ABA)-insensitive Vicia faba mutant, fia (fava bean impaired in ABA-induced stomatal closure) had previously been isolated. In this study, it was investigated how FIA functions in ABA signalling in guard cells of Vicia faba. Unlike ABA, methyl jasmonate (MeJA), H2O2, and nitric oxide (NO) induced stomatal closure in the fia mutant. ABA did not induce production of either reactive oxygen species or NO in the mutant. Moreover, ABA did not suppress inward-rectifying K+ (K-in) currents or activate ABA-activated protein kinase (AAPK) in mutant guard cells. These results suggest that FIA functions as an early signal component upstream of AAPK activation in ABA signalling but does not function in MeJA signalling in guard cells of Vicia faba.

DOI： 10.1093/jxb/err369

alpha-Tocopherol Sensitizes Human Leukemia HL-60 Cells to Apoptosis Induced by Benzyl Isothiocyanate Reviewed

Naomi Abe, Tomomi Shimizu, Noriyuki Miyoshi, Yoshiyuki Murata, Yoshimasa Nakamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 76 ( 2 ) 381 - 383 2012.2

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Pre-treatment with alpha-tocopherol (alpha-Toc) potentiated cytotoxicity induction by benzyl isothiocyanate (BITC). Biochemical events related to apoptosis, such as DNA ladder formation and caspase-3 activation, were also enhanced by alpha-Toc. These results suggest a significant role of the caspase-3 pathway in apoptosis induction regulated by alpha-Toc in combination.

DOI： 10.1271/bbb.110665

Cytotoxicity of Benzyl Isothiocyanate in Normal Renal Proximal Tubular Cells and Its Modulation by Glutathione Reviewed

Naomi Abe, Masashi Okuhira, Chiharu Tsutsui, Yoshiyuki Murata, Yoshimasa Nakamura

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 60 ( 7 ) 1887 - 1892 2012.2

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

In the present study, we examined the toxicity of benzyl 1TC (BITC) and its urinary mercapturic acid metabolite (BITC-NAC), using a normal renal proximal tubular cell line, pig LLC-PK1. BITC increased cell death with an IC50 value of about 7 mu M, whereas the cytotoxic effect of BITC-NAC was five times weaker than that of BITC. We observed a significant necrosis of the compounds on LLC-PK1 cells with oxidative stress. In the presence of 5 mM glutathione (GSH), comparable to physiological levels, the cytotoxicity of BITC-NAC as well as BITC was significantly reduced. Furthermore, the increase in intracellular GSH levels by pretreatment with NAC before the BITC treatment resulted ill inhibition of the BITC-induced necrotic events as well as intracellular oxidative stress. These results suggest that GSH is a determinant of cellular resistance against the BITC-mediated and oxidative stress-dependent cytotoxicity in renal proximal tubular cells.

DOI： 10.1021/jf2052042

K252a-sensitive protein kinases but not okadaic acid-sensitive protein phosphatases regulate methyl jasmonate-induced cytosolic Ca2+ oscillation in guard cells of Arabidopsis thaliana Reviewed

Mohammad Anowar Hossain, Shintaro Munemasa, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 168 ( 16 ) 1901 - 1908 2011.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

Methyl jasmonate (MeJA) induces stomatal closure similar to abscisic acid (ABA), and MeJA signaling in guard cells shares some signal components with ABA signaling. As part of this process, MeJA as well as ABA induce the elevation and oscillation of cytosolic free-calcium concentrations ([Ca2+](cyt)) in guard cells. While abscisic acid-induced [Ca2+](cyt) oscillation has been extensively studied, MeJA-induced [Ca2+](cyt) oscillation is less well understood. In this study, we investigated the effects of K252a (a broad-range protein kinase inhibitor) and okadaic acid (OA, a protein phosphatase 1 and 2A inhibitor) on MeJA-induced [Ca2+](cyt) oscillation in guard cells of Arabidopsis thaliana ecotype Columbia expressing the Ca2+ reporter yellow cameleon 3.6. The protein kinase inhibitor K252a abolished MeJA-induced stomatal closure and reduced MeJA-elicited [Ca2+](cyt) oscillation. The protein phosphatase inhibitor OA, on the other hand, did not inhibit these processes. These results suggest that MeJA signaling involves activation of K252a-sensitive protein kinases upstream of [Ca2+](cyt) oscillation but not activation of an OA-sensitive protein phosphatase in guard cells of A. thaliana ecotype Columbia. (C) 2011 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.jplph.2011.05.004

Allyl isothiocyanate (AITC) induces stomatal closure in Arabidopsis Reviewed

Md. Atiqur Rahman Khokon, Md. Sarwar Jahan, Taniya Rahman, Mohammad Anowar Hossain, Daichi Muroyama, Ikuko Minami, Shintaro Munemasa, Izumi C. Mori, Yoshimasa Nakamura, Yoshiyuki Murata

PLANT CELL AND ENVIRONMENT 34 ( 11 ) 1900 - 1906 2011.11

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Isothiocyanates (ITCs) are degradation products of glucosinolates in crucifer plants and have repellent effect on insects, pathogens and herbivores. In this study, we report that exogenously applied allyl isothiocyanate (AITC) induced stomatal closure in Arabidopsis via production of reactive oxygen species (ROS) and nitric oxide (NO), and elevation of cytosolic Ca2+. AITC-induced stomatal closures were partially inhibited by an inhibitor of NADPH oxidase and completely inhibited by glutathione monoethyl ester (GSHmee). AITC-induced stomatal closure and ROS production were examined in abscisic acid (ABA) deficient mutant aba2-2 and methyl jasmonate (MeJA)-deficient mutant aos to elucidate involvement of endogenous ABA and MeJA. Genetic evidences have demonstrated that AITC-induced stomatal closure required MeJA priming but not ABA priming. These results raise the possibility that crucifer plants produce ITCs to induce stomatal closure, leading to suppression of water loss and invasion of fungi through stomata.

DOI： 10.1111/j.1365-3040.2011.02385.x

Roles of intracellular hydrogen peroxide accumulation in abscisic acid signaling in Arabidopsis guard cells Reviewed

Rayhanur Jannat, Misugi Uraji, Miho Morofuji, Mohammad Muzahidul Islam, Rachel E. Bloom, Yoshimasa Nakamura, C. Robertson McClung, Julian I. Schroeder, Izumi C. Mori, Yoshiyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 168 ( 16 ) 1919 - 1926 2011.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

Reactive oxygen species (ROS), including hydrogen peroxide (H(2)O(2)), are among the important second messengers in abscisic acid (ABA) signaling in guard cells. In this study, to investigate specific roles of H(2)O(2) in ABA signaling in guard cells, we examined the effects of mutations in the guard cell-expressed catalase (CAT) genes, CAT1 and CAT3, and of the CAT inhibitor 3-aminotriazole (AT) on stomata! movement. The cat3 and cat1 cat3 mutations significantly reduced CAT activities, leading to higher basal level of H(2)O(2) in guard cells, when assessed by 2',7'-dichlorodihydrofluorescein, whereas they did not affect stomatal aperture size under non-stressed condition. In addition, AT-treatment at concentrations that abolish CAT activities, showed trivial affect on stomatal aperture size, while basal H(2)O(2) level increased extensively. In contrast, cat mutations and AT-treatment potentiated ABA-induced stomata! closure. Inducible ROS production triggered by ABA was observed in these mutants and wild type as well as in AT-treated guard cells. These results suggest that ABA-inducible cytosolic H(2)O(2) elevation functions in ABA-induced stomatal closure, while constitutive increase of H(2)O(2) do not cause stomatal closure. (C) 2011 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.jplph.2011.05.006

Negative regulation of abscisic acid-induced stomatal closure by glutathione in Arabidopsis Reviewed

Eiji Okuma, Md Sarwar Jahan, Shintaro Munemasa, Mohammad Anowar Hossain, Daichi Muroyama, Mohammad Mahbub Islam, Ken'ichi Ogawa, Megumi Watanabe-Sugimoto, Yoshimasa Nakamura, Yasuaki Shimoishi, Izumi C. Mori, Yoshiyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 168 ( 17 ) 2048 - 2055 2011.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

We found that glutathione (GSH) is involved in abscisic acid (ABA)-induced stomatal closure. Regulation of ABA signaling by GSH in guard cells was investigated using an Arabidopsis mutant. cad2-1. that is deficient in the first GSH biosynthesis enzyme, gamma-glutamylcysteine synthetase, and a GSH-decreasing chemical, 1-chloro-2,4-dinitrobenzene (CDNB). Glutathione contents in guard cells decreased along with ABA-induced stomata! closure. Decreasing GSH by both the cad2-1 mutation and CDNB treatment enhanced ABA-induced stomata! closure. Glutathione monoethyl ester (GSHmee) restored the GSH level in cad2-1 guard cells and complemented the stomatal phenotype of the mutant. Depletion of GSH did not significantly increase ABA-induced production of reactive oxygen species in guard cells and GSH did not affect either activation of plasma membrane Ca2+-permeable channel currents by ABA or oscillation of the cytosolic free Ca2+ concentration induced by ABA. These results indicate that GSH negatively modulates a signal component other than ROS production and Ca2+ oscillation in ABA signal pathway of Arabidopsis guard cells. (C) 2011 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.jplph.2011.06.002

Localized cysteine sulfenic acid formation by vascular endothelial growth factor: role in endothelial cell migration and angiogenesis Reviewed

Nihal Kaplan, Norifumi Urao, Eiji Furuta, Seok-Jo Kim, Masooma Razvi, Yoshimasa Nakamura, Ronald D. McKinney, Leslie B. Poole, Tohru Fukai, Masuko Ushio-Fukai

FREE RADICAL RESEARCH 45 ( 10 ) 1124 - 1135 2011.10

Language：English Publishing type：Research paper (scientific journal) Publisher：INFORMA HEALTHCARE

Reactive oxygen species (ROS) are important mediators for VEGF receptor 2 (VEGFR2) signalling involved in angiogenesis. The initial product of Cys oxidation, cysteine sulfenic acid (Cys-OH), is a key intermediate in redox signal transduction; however, its role in VEGF signalling is unknown. We have previously demonstrated IQGAP1 as a VEGFR2 binding scaffold protein involved in ROS-dependent EC migration and post-ischemic angiogenesis. Using a biotin-labelled Cys-OH trapping reagent, we show that VEGF increases protein-Cys-OH formation at the lamellipodial leading edge where it co-localizes with NADPH oxidase and IQGAP1 in migrating ECs, which is prevented by IQGAP1 siRNA or trapping of Cys-OH with dimedone. VEGF increases IQGAP1-Cys-OH formation, which is prevented by N-acetyl cysteine or dimedone, which inhibits VEGF-induced EC migration and capillary network formation. In vivo, hindlimb ischemia in mice increases CysOH formation in small vessels and IQGAP1 in ischemic tissues. In summary, VEGF stimulates localized formation of Cys-OH-IQGAP1 at the leading edge, thereby promoting directional EC migration, which may contribute to post-natal angiogenesis in vivo. Thus, targeting Cys-oxidized proteins at specific compartments may be the potential therapeutic strategy for various angiogenesis-dependent diseases.

DOI： 10.3109/10715762.2011.602073

The Roles of CATALASE2 in Abscisic Acid Signaling in Arabidopsis Guard Cells Reviewed

Rayhanur Jannat, Misugi Uraji, Miho Morofuji, Mohammad Anowar Hossain, Mohammad Muzahidul Islam, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 75 ( 10 ) 2034 - 2036 2011.10

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

We investigated the roles of catalase (CAT) in abscisic acid (ABA)-induced stomatal closure using a cat2 mutant and an inhibitor of CAT, 3-aminotriazole (AT). Constitutive reactive oxygen species (ROS) accumulation due to the CAT2 mutation and AT treatment did not affect stomatal aperture in the absence of ABA, whereas ABA-induced stomatal closure, ROS production, and [Ca2+](cyt) oscillation were enhanced.

DOI： 10.1271/bbb.110344

Histochemical quantification of glutathione contents in guard cells of Arabidopsis thaliana Reviewed

Md. Sarwar Jahan, Yoshimasa Nakamura, Yoshiyuki Murata

SCIENCEASIA 37 ( 3 ) 281 - 284 2011.9

Language：English Publishing type：Research paper (scientific journal) Publisher：THAILANDS NATL SCIENCE & TECHNOLOGY DEVELOPMENT AGENCY

Glutathione (GSH), one of the most abundant low molecular-weight thiol compounds, maintains redox homoeostasis in plants. To measure GSH content in guard cells of Arabidopsis thaliana, we have developed a technique to quantify the GSH content in guard cells using the staining dye monochlorobimane (MCB). The fluorescent intensity of glutathione S-bimane (GSB) gradually increased in guard cells with increasing incubation time and reached steady state 2 h after epidermal tissues were treated with MCB. The guard cells contained larger amount of GSH content than other cells of the leaves except trichome cell. MCB staining showed that guard cells of a GSH deficient mutant, accumulated significantly lower GSH content than that of wild type guard cells. When the guard cells were treated with 1-chloro-2,4-dinitrobenzene to reduce GSH content in the guard cells, the GSB fluorescence in the guard cells was abolished. In addition, GSH monoethyl ester restored GSH level in the guard cells of ch1-1 mutant plants. These results suggest that GSH content in guard cells can be quantified using MCB dye.

DOI： 10.2306/scienceasia1513-1874.2011.37.281

Hydogen peroxide-dependent photocytotoxicity by phloxine B, a xanthene-type food colorant Reviewed

Hang Qi, Hiroshi Takano, Yoji Kato, Qian Wu, Chiharu Ogata, Beiwei Zhu, Yoshiyuki Murata, Yoshimasa Nakamura

BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS 1810 ( 7 ) 704 - 712 2011.7

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Background: Phloxine B (PhB; 2',4',5',7'-tetrabromo-4,5,6,7-tetrachloro-fluorescein), an artificial xanthene colorant, has been used as a red coloring agent in drugs and cosmetics as well as foods in some countries. However, little effort has been devoted to the study of this colorant as a potentially useful medicinal agent.
Methods: We investigated the daily light-induced photocytotoxicity of PhB in two human leukemia cells, HL-60 and Jurkat, and its underlying mechanisms by in vitro experiments using antioxidants.
Reuslts and conclusions: PhB inhibited cell proliferation more preferentially to HL-60 cells than to Jurkat cells. Co-treatment of catalase completely blocked the photocytotoxicity by PhB in HL-60 cells, whereas the effect of histidine was only partial, suggesting that hydrogen peroxide (H(2)O(2)), rather than singlet oxygen, might be a prerequisite for the PhB-induced HL-60 cell death. Actually, PhB produced a significant amount of H(2)O(2) in the media as well as in the cells in concentration- and light-dependent manners. Furthermore, methionine, a hypochlorous acid (HOCl) scavenger, also significantly attenuated the cytotoxicity in HL-60 cells, but not in Jurkat cells, indicating the involvement of myeloperoxidase (MPO)-dependent hypohalous acid formation during the photocytotoxicity. In vitro experiments revealed that halogenated tyrosine was generated from the reaction of bovine serum albumin with PhB and HL-60 cell lysate. The present findings suggested that PhB induced a differential photodynamic action in the MPO-containing leukemia cells through an H(2)O(2)-dependent mechanism.
General significance: Our findings provide new insights into the molecular mechanisms underlying the PhB-induced apoptosis and also evaluated PhB as a promising PDT agent. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.bbagen.2011.04.010

Photostability of Lycopene Dispersed in an Aqueous Solution Reviewed

Masayuki Nishino, Takeshi Miuchi, Makoto Sakata, Atsushi Nishida, Yoshiyuki Murata, Yoshimasa Nakamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 75 ( 7 ) 1389 - 1391 2011.7

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Lycopene dispersed in aqueous solutions with different dissolved oxygen contents was photo-irradiated by using a xenon weather meter, and the contents of lycopene and dissolved oxygen were measured. Both the degradation of lycopene and the consumption of dissolved oxygen followed a first-order kinetics model. There was a proportional relationship between the degradation content of lycopene and the consumption of dissolved oxygen. These results indicate that dissolved oxygen would also be involved in the photolysis of lycopene.

DOI： 10.1271/bbb.110154

Involvement of Endogenous Abscisic Acid in Methyl Jasmonate-Induced Stomatal Closure in Arabidopsis Reviewed

Mohammad Anowar Hossain, Shintaro Munemasa, Misugi Uraji, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

PLANT PHYSIOLOGY 156 ( 1 ) 430 - 438 2011.5

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC PLANT BIOLOGISTS

In this study, we examined the involvement of endogenous abscisic acid (ABA) in methyl jasmonate (MeJA)-induced stomatal closure using an inhibitor of ABA biosynthesis, fluridon (FLU), and an ABA-deficient Arabidopsis (Arabidopsis thaliana) mutant, aba2-2. We found that pretreatment with FLU inhibited MeJA-induced stomatal closure but not ABA-induced stomatal closure in wild-type plants. The aba2-2 mutation impaired MeJA-induced stomatal closure but not ABA-induced stomatal closure. We also investigated the effects of FLU and the aba2-2 mutation on cytosolic free calcium concentration ([Ca2+](cyt)) in guard cells using a Ca2+-reporter fluorescent protein, Yellow Cameleon 3.6. In wild-type guard cells, FLU inhibited MeJA-induced [Ca2+](cyt) elevation but not ABA-induced [Ca2+](cyt) elevation. The aba2-2 mutation did not affect ABA-elicited [Ca2+](cyt) elevation but suppressed MeJA-induced [Ca2+](cyt) elevation. We also tested the effects of the aba2-2 mutation and FLU on the expression of MeJA-inducible VEGETATIVE STORAGE PROTEIN1 (VSP1). In the aba2-2 mutant, MeJA did not induce VSP1 expression. In wild-type leaves, FLU inhibited MeJA-induced VSP1 expression. Pretreatment with ABA at 0.1 mu M, which is not enough concentration to evoke ABA responses in the wild type, rescued the observed phenotypes of the aba2-2 mutant. Finally, we found that in wild-type leaves, MeJA stimulates the expression of 9-CIS-EPOXYCAROTENOID DIOXYGENASE3, which encodes a crucial enzyme in ABA biosynthesis. These results suggest that endogenous ABA could be involved in MeJA signal transduction and lead to stomatal closure in Arabidopsis guard cells.

DOI： 10.1104/pp.111.172254

(-)-Epigallocatechin-3-gallate suppresses growth of AZ521 human gastric cancer cells by targeting the DEAD-box RNA helicase p68 Reviewed

Tomoko Tanaka, Takeshi Ishii, Daisuke Mizuno, Taiki Mori, Ryoichi Yamaji, Yoshimasa Nakamura, Shigenori Kumazawa, Tsutomu Nakayama, Mitsugu Akagawa

FREE RADICAL BIOLOGY AND MEDICINE 50 ( 10 ) 1324 - 1335 2011.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

(-)-Epigallocatechin-3-gallate (EGCG), the most abundant and biologically active polyphenol in green tea, induces apoptosis and suppresses proliferation of cancer cells by modulating multiple signal transduction pathways. However, the fundamental mechanisms responsible for these cancer-preventive effects have not been clearly elucidated. Recently, we found that EGCG can covalently bind to cysteine residues in proteins through autoxidation and subsequently modulate protein function. In this study, we demonstrate the direct binding of EGCG to cellular proteins in AZ521 human gastric cancer cells by redox-cycle staining. We comprehensively explored the binding targets of EGCG from EGCG-treated A2521 cells by proteomics techniques combined with the boronate-affinity pull-down method. The DEAD-box RNA helicase p68, which is overexpressed in a variety of tumor cells and plays an important role in cancer development and progression, was identified as a novel EGCG-binding target. Exposure of AZ521 cells to EGCG lowered the p68 level dose dependently. The present findings show that EGCG inhibits AZ521 cell proliferation by preventing beta-catenin oncogenic signaling through proteasomal degradation of p68 and provide a new perspective on the molecular mechanism of EGCG action. (C) 2011 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.freeradbiomed.2011.01.024

Involvement of extracellular oxidative burst in salicylic acid-induced stomatal closure in Arabidopsis Reviewed

Md. Atiqur Rahman Khokon, Eiji Okuma, Mohammad Anowar Hossain, Shintaro Munemasa, Misugi Uraji, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

PLANT CELL AND ENVIRONMENT 34 ( 3 ) 434 - 443 2011.3

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL PUBLISHING, INC

Salicylic acid (SA), a ubiquitous phenolic phytohormone, is involved in many plant physiological processes including stomatal movement. We analysed SA-induced stomatal closure, production of reactive oxygen species (ROS) and nitric oxide (NO), cytosolic calcium ion ([Ca2+](cyt)) oscillations and inward-rectifying potassium (K+(in)) channel activity in Arabidopsis. SA-induced stomatal closure was inhibited by pre-treatment with catalase (CAT) and superoxide dismutase (SOD), suggesting the involvement of extracellular ROS. A peroxidase inhibitor, SHAM (salicylhydroxamic acid) completely abolished SA-induced stomatal closure whereas neither an inhibitor of NADPH oxidase (DPI) nor atrbohD atrbohF mutation impairs SA-induced stomatal closures. 3,3'-Diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) stainings demonstrated that SA induced H(2)O(2) and O(2)- production. Guard cell ROS accumulation was significantly increased by SA, but that ROS was suppressed by exogenous CAT, SOD and SHAM. NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) suppressed the SA-induced stomatal closure but did not suppress guard cell ROS accumulation whereas SHAM suppressed SA-induced NO production. SA failed to induce [Ca2+](cyt) oscillations in guard cells whereas K+(in) channel activity was suppressed by SA. These results indicate that SA induces stomatal closure accompanied with extracellular ROS production mediated by SHAM-sensitive peroxidase, intracellular ROS accumulation and K+(in) channel inactivation.

DOI： 10.1111/j.1365-3040.2010.02253.x

The Arabidopsis Calcium-Dependent Protein Kinase, CPK6, Functions as a Positive Regulator of Methyl Jasmonate Signaling in Guard Cells Reviewed

Shintaro Munemasa, Mohammad Anowar Hossain, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

PLANT PHYSIOLOGY 155 ( 1 ) 553 - 561 2011.1

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC PLANT BIOLOGISTS

Previous studies have demonstrated that methyl jasmonate (MeJA) induces stomatal closure dependent on change of cytosolic free calcium concentration in guard cells. However, these molecular mechanisms of intracellular Ca2+ signal perception remain unknown. Calcium-dependent protein kinases (CDPKs) function as Ca2+ signal transducers in various plant physiological processes. It has been reported that four Arabidopsis (Arabidopsis thaliana) CDPKs, CPK3, CPK6, CPK4, and CPK11, are involved in abscisic acid signaling in guard cells. It is also known that there is an interaction between MeJA and abscisic acid signaling in guard cells. In this study, we examined the roles of these CDPKs in MeJA signaling in guard cells using Arabidopsis mutants disrupted in the CDPK genes. Disruption of the CPK6 gene impaired MeJA-induced stomatal closure, but disruption of the other CDPK genes did not. Despite the broad expression pattern of CPK6, we did not find other remarkable MeJA-insensitive phenotypes in the cpk6-1 mutant. The whole-cell patch-clamp analysis revealed that MeJA activation of nonselective Ca2+-permeable cation channels is impaired in the cpk6-1 mutant. Consistent with this result, MeJA-induced transient cytosolic free calcium concentration increments were reduced in the cpk6-1 mutant. MeJA failed to activate slow-type anion channels in the cpk6-1 guard cells. Production of early signal components, reactive oxygen species and nitric oxide, in guard cells was elicited by MeJA in the cpk6-1 mutant as in the wild type. These results provide genetic evidence that CPK6 has a different role from CPK3 and functions as a positive regulator of MeJA signaling in Arabidopsis guard cells.

DOI： 10.1104/pp.110.162750

The Involvement of Intracellular Glutathione in Methyl Jasmonate Signaling in Arabidopsis Guard Cells Reviewed

Nasima Akter, Muhammad Abdus Sobahan, Mohammad Anowar Hossain, Misugi Uraji, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 74 ( 12 ) 2504 - 2506 2010.12

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

We examined the involvement of intracellular glutathione (GSH) in methyl jasmonate (MeJA) signaling. The chlorinal-1 (ch1-1) mutation decreased GSH in guard cells and narrowed the stomata! aperture. GSH monoethyl ester increased intracellular GSH, diminishing this phenotype. GSH did not affect MeJA-induced reactive oxygen species production or cytosolic Ca2+ oscillation, suggesting that GSH modulates MeJA signaling downstream of production and oscillation.

DOI： 10.1271/bbb.100513

Covalent Binding of Tea Catechins to Protein Thiols: The Relationship between Stability and Electrophilic Reactivity Reviewed

Taiki Mori, Takeshi Ishii, Mitsugu Akagawa, Yoshimasa Nakamura, Tsutomu Nakayama

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 74 ( 12 ) 2451 - 2456 2010.12

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

In this study, we investigated the relationship between the stability of catechins and their electrophilic reactivity with proteins. The stability of catechins was evaluated by HPLC analysis. Catechol-type catechins were stable in a neutral buffer, but pyrogallol-type catechins, such as (-)-epigallocatechin gallate (EGCg), were unstable. The electrophilic reactivity of catechins with thiol groups in a model peptide and a protein was confirmed by both mass spectrometry and electrophoresis/blotting with redox-cycling staining. In a comparison of several catechins, pyrogallol-type catechins had higher reactivity with protein thiols than catechol-type catechins. The instability and reactivity of EGCg were enhanced in an alkaline pH buffer. The reactivity of EGCg was reduced by antioxidants due to their ability to prevent EGCg autoxidation. These results indicate that the instability against oxidation of catechins is profoundly related to their electrophilic reactivity. Consequently, the difference in these properties of tea catechins can contribute to the magnitude of their biological activities.

DOI： 10.1271/bbb.100509

Yeast Elicitor-Induced Stomatal Closure and Peroxidase-Mediated ROS Production in Arabidopsis Reviewed

Md. Atiqur Rahman Khokon, Mohammad Anowar Hossain, Shintaro Munemasa, Misugi Uraji, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

PLANT AND CELL PHYSIOLOGY 51 ( 11 ) 1915 - 1921 2010.11

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Yeast elicitor (YEL) induces stomatal closure. We investigated reactive oxygen species (ROS) production, nitric oxide (NO) production and [Ca(2+)](cyt) oscillations to clarify YEL signaling in Arabidopsis guard cells. YEL induced ROS accumulation in guard cells. A peroxidase inhibitor [salicylhydroxamic acid (SHAM)] inhibited the stomatal closure and the ROS accumulation, but neither the atrbohD atrbohF mutation nor an NADPH oxidase inhibitor [diphenylene iodonium chloride (DPI)] had any effect. An NO scavenger [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3oxide (cPTIO)] inhibited the YEL-induced stomatal closure and SHAM abolished NO production. YEL-elicited [Ca(2+)] cyt oscillations were inhibited by SHAM but not by the atrbohD atrbohF mutation. These results indicate that YEL induces stomatal closure accompanied by ROS production mediated by peroxidases and NO production.

DOI： 10.1093/pcp/pcq145

Chitosan-Induced Stomatal Closure Accompanied by Peroxidase-Mediated Reactive Oxygen Species Production in Arabidopsis Reviewed

Md Atiqur Rahman Khokon, Misugi Uraji, Shintaro Munemasa, Eiji Okuma, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 74 ( 11 ) 2313 - 2315 2010.11

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Chitosan induced stomatal closure in wild type-plants and NADPH oxidase knock-out mutants (atrbohD atrbohF), and reactive oxygen species (ROS) production in wild-type guard cells. Closure and production were completely abolished by catalase and a peroxidase inhibitor. These results indicate that chitosan induces ROS production mediated by peroxidase, resulting in stomata! closure.

DOI： 10.1271/bbb.100340

The Effects of Methylglyoxal on Glutathione S-Transferase from Nicotiana tabacum Reviewed

Md Anamul Hoque, Misugi Uraji, Mst Nasrin Akhter Banu, Izumi C. Mori, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 74 ( 10 ) 2124 - 2126 2010.10

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Methylglyoxal (MG) is one of the aldehydes that accumulate in plants under environmental stress. Glutathione S-transferases (GSTs) play important roles, including detoxification, in the stress tolerance systems of plants. To determine the effects of MG, we characterized recombinant GST. MG decreased GST activity and thiol contents with increasing Km. GST can serve as a target of MG modification, which is suppressed by application of reduced glutathione.

DOI： 10.1271/bbb.100393

Cytosolic Alkalization and Cytosolic Calcium Oscillation in Arabidopsis Guard Cells Response to ABA and MeJA Reviewed

Mohammad Mahbub Islam, Mohammad Anowar Hossain, Rayhanur Jannat, Shintaro Munemasa, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

PLANT AND CELL PHYSIOLOGY 51 ( 10 ) 1721 - 1730 2010.10

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Abscisic acid (ABA)- and methyl jasmonate (MeJA)-induced stomatal closure are accompanied by cytosolic alkalization in guard cells. However, it remains to be clarified how the alkalization functions in not only ABA signaling but also MeJA. We investigated cytosolic alkalization in guard cells during ABA-, MeJA- and Ca(2+)-induced stomatal closure of wild type, abi1-1, abi2-1, ost1-2 and coi1 using a pH-sensitive fluorescent dye, BCECF-AM. ABA induced cytosolic alkalization in guard cells of wild-type and coi1 but not in ost1-2 guard cells whereas MeJA elicited cytosolic alkalization in wild-type and ost1-2 guard cells but not in coi1. Neither ABA nor MeJA induced cytosolic alkalization in abi1-1 and abi2-1 guard cells. Exogenous Ca(2+) induced stomatal closure accompanied by cytosolic alkalization in guard cells of wild-type, abi1-1, abi2-1, ost1-2 and coi1 plants. An agent to acidify cytosol, butyrate, suppressed Ca(2+) -induced cytosolic alkalization and ABA-, MeJA- and Ca(2+) -induced cytosolic Ca(2+) oscillation in wild-type guard cells to prevent stomatal closure. These results indicate that cytosolic alkalization and cytosolic Ca(2+) oscillation coordinately function in ABA and MeJA signaling in Arabidopsis guard cells.

DOI： 10.1093/pcp/pcq131

Proline and Glycinebetaine Ameliorated NaCl Stress via Scavenging of Hydrogen Peroxide and Methylglyoxal but Not Superoxide or Nitric Oxide in Tobacco Cultured Cells Reviewed

Mst Nasrin Akhter Banu, Md Anamul Hoque, Megumi Watanabe-Sugimoto, Mohammad Muzahidul Islam, Misugi Uraji, Ken Matsuoka, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 74 ( 10 ) 2043 - 2049 2010.10

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Efficient detoxification of the reactive oxygen species, nitric oxide (NO) and methylglyoxal (MG), provides protection against NaCl-induced damage in plants. To elucidate the protective mechanisms of proline and glycinebetaine (betaine) against NaCl stress, intracellular levels of hydrogen peroxide (H2O2), superoxide (O-2(-)), NO, and MG were investigated in tobacco Bright Yellow-2 cells. The Levels of H2O2, O-2(-), NO and MG were higher in the short-term and long-term NaCl-stressed cells than in the non-stressed cells, whereas the O-2(-) level was higher in the long-term stressed cells. Exogenous proline and betaine decreased the H2O2 level in both the short-term and the long-term NaCl-stressed cells and the MG level in the long-term NaCl-stressed cells, but did not change the O-2(-) or NO levels. Under salt stress, both proline and betaine increased the transcription levels of glutathione peroxidase, which can contribute to the reduction of H2O2. In conclusion, proline and betaine mitigated salt stress via reduction of H2O2 accumulation during short-term incubation and via reduction of the accumulation of H2O2 and MG during long-term incubation.

DOI： 10.1271/bbb.100334

Artificial Food Colorants Inhibit Superoxide Production in Differentiated HL-60 Cells Reviewed

Hang Qi, Machiko Kawagishi, Motoko Yoshimoto, Hiroshi Takano, Beiwei Zhu, Yasuaki Shimoishi, Mikiro Tada, Yoshiyuki Murata, Yoshimasa Nakamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 74 ( 8 ) 1725 - 1728 2010.8

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

We tested synthetic food colorants for their antioxidative potential by the in vitro superoxide generation assay in differentiated HL-60 cells in response to phorbol ester. Among the 12 colorants tested, such fluorescein-type red colorants as rose bengal showed potent inhibitory activity without any cytotoxicity under dark conditions. The intracellular accumulation and superoxide anion scavenging effect of rose bengal were at least partly involved in the inhibitory activity.

DOI： 10.1271/bbb.100314

Roles of AtTPC1, Vacuolar Two Pore Channel 1, in Arabidopsis Stomatal Closure Reviewed

Mohammad Mahbub Islam, Shintaro Munemasa, Mohammad Anowar Hossain, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

PLANT AND CELL PHYSIOLOGY 51 ( 2 ) 302 - 311 2010.2

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Abscisic acid (ABA) induces production of reactive oxygen species (ROS) and nitric oxide (NO), elevation of the cytosolic free calcium ion concentration ([Ca(2+)](cyt)) and cytosolic pH (pH(cyt)), and activation of S-type anion channels in guard cells, causing stomatal closure. To investigate whether Arabidopsis Two pore channel 1 (AtTPC1) that encodes the slow vacuolar (SV) channel is involved in stomatal closure, we examined stomatal movements and mobilization of second messengers in the attpc1-2 loss-of-function mutant in response to ABA, methyl jasmonate (MeJA) and Ca(2+). Both ABA and MeJA elicited production of ROS and NO, [Ca(2+)] cyt oscillations, cytosolic alkalization and activation of S-type anion channel currents to lead to stomatal closure in the attpc1-2 mutant as well as the wild type. Unlike the wild type, in the attpc1-2 mutant exogenous Ca(2+) neither induced stomatal closure nor activated plasma membrane S-type anion channel currents despite [Ca(2+)] cyt elevation. These results indicate that AtTPC1 functions in response to external Ca(2+) but not to ABA and MeJA in Arabidopsis guard cells and suggest that AtTPC1 could be involved in priming of plasma membrane S-type anion channels by external Ca(2+) in Arabidopsis guard cells.

DOI： 10.1093/pcp/pcq001

A fraction of unripe kiwi fruit extract regulates adipocyte differentiation and function in 3T3-L1 cells Reviewed

Daigo Abe, Takeshi Saito, Yasutaka Kubo, Yoshimasa Nakamura, Keizo Sekiya

BIOFACTORS 36 ( 1 ) 52 - 59 2010.1

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY

Adipocyte dysfunction is strongly associated with the development of insulin resistance and diabetes, and regulation of adipogenesis is important in prevention of diabetes. We prepared a 100% methanol fraction of methanolic extract from unripe kiwi fruit (Actinidia deliciosa), designated KMF (kiwi fruit methanol fraction) When applied to 3T3-L1 preadipocyte cells, KMF promoted adipocyte differentiation, increased glycerol-3-phosphate dehydrogenase (GPDH) activity, and increased triglyceride (TG) content. KMF markedly increased mRNA expression of peroxisome proliferator-activated receptor gamma (PPAR gamma)-the master adipogenic transcription factor-and its target genes. Moreover, KMF increased mRNA expression and protein secretion of adiponectin, whereas mRNA expression and secretion of monocyte chemoattractant protein-1 (MCP-1) and interleukin-6 (IL-6) were decreased. Compared with troglitazone, KMF decreased the production of reactive oxygen species (ROS) and nuclear factor-kappaB (NF kappa B) activation. Glucose uptake was stimulated by KMF in differentiated 3T3-L1 adipocytes. Taken together, these results indicate that KMF may exert beneficial effects against diabetes via its ability to regulate adipocyte differentiation and function. (C) 2010 International Union of Biochemistry and Molecular Biology, Inc.

DOI： 10.1002/biof.70

Identification and Characterization of Sesaminol Metabolites in the Liver Reviewed

Mika Mochizuki, Yoshikazu Tsuchie, Yoshimasa Nakamura, Toshihiko Osawa

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 57 ( 21 ) 10429 - 10434 2009.11

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Sesame seeds contain a number of antioxidants, such as sesamin, sesamolin, sesaminol, and sesaminol glucosides. Sesaminol triglucoside was reported to suppress oxidative stress in vivo, but little is known about the metabolism of this potentially important compound. Therefore, we have studied the metabolites of sesaminol formed in the rat liver S9 mix and excreted in the liver of rats ingesting sesaminol triglucoside for 24 h. Nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses revealed that rat liver S9 mix transformed the sesaminol into a catechol-type metabolite. On the basis of a previous study with sesame lignans by culturing the genus Aspergillus, sesaminol-6-catechol was identified as the major metabolite. Sesaminol was further converted into 5 ''-methylated sesaminol-6-catechol by catechol-O-methyltransferase. Moreover, we successfully detected these metabolites in the liver of rats ingesting the sesaminol triglucoside.

DOI： 10.1021/jf901939m

Proline and Glycinebetaine Confer Cadmium Tolerance on Tobacco Bright Yellow-2 Cells by Increasing Ascorbate-Glutathione Cycle Enzyme Activities Reviewed

Mohammad Muzahidul Islam, Md. Anamul Hoque, Eiji Okuma, Rayhanur Jannat, Mst. Nasrin Akhter Banu, Md. Sarwar Jahan, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 73 ( 10 ) 2320 - 2323 2009.10

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Cadmium (Cd) stress significantly decreased membrane integrity and impaired the ascorbate (ASC)-glutathione (GSH) cycle in tobacco Bright Yellow-2 cells. Exogenous application of proline and glycinebetaine (betaine) significantly restored the membrane integrity and increased the activities of ASC-GSH cycle enzymes under Cd stress without maintenance of the rich ASC or GSH pools. Moreover, proline offered more efficient protection against Cd stress than betaine.

DOI： 10.1271/bbb.90305

Catechol Type Polyphenol Is a Potential Modifier of Protein Sulfhydryls: Development and Application of a New Probe for Understanding the Dietary Polyphenol Actions Reviewed

Takeshi Ishii, Miki Ishikawa, Noriyuki Miyoshi, Mayuko Yasunaga, Mitsugu Akagawa, Koji Uchida, Yoshimasa Nakamura

CHEMICAL RESEARCH IN TOXICOLOGY 22 ( 10 ) 1689 - 1698 2009.10

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

The oxidation of dietary polyphenols with a catechol structure leads to the formation of an o-quinone structure, which rapidly reacts with sulfhydryls such as glutathione and protein cysteine residues. This modification may be important for understanding the redox regulation of cell functions by polyphenols. In this study, to investigate the catechol modification of protein sulthydryls, we used 3,4-dihydroxyphenyl acetic acid (DPA) as a model catechol compound and developed a new probe to directly detect protein modification by catechol type polyphenols using a biotinylated DPA (Bio-DPA). The oxidation-dependent electrophilic reactivity of DPA with peptide sulfhydryls was confirmed by both mass spectrometry and nuclear magnetic resonance spectroscopy. When RL34 cells were treated with Bio-DPA, the significant incorporation of Bio-DPA into a 40 kDa protein was observed by Western blot analysis. The band was identified by mass spectrometry as the cytoskeletal protein, beta-actin. This identification was confirmed by the pull-down assay with anti-beta-actin antibody. To examine the reactivity of the catechol type polyphenols, such as flavonoids, to endogenous beta-actin, RL34 cells were coexposed to Bio-DPA and the flavonoids quercetin, (-)-epicatechin, and (-)-epicatechin gallate. Upon exposure of the cells to Bio-DPA in the presence of the flavonoids, we observed a significant decrease in the DPA-modified beta-actin. These results indicate that beta-actin is one of the major targets of protein modification by catechol type polyphenols and that Bio-DPA is an useful probe for understanding the redox regulation by dietary polyphenols. Furthermore, Keap1, a scaffold protein to the actin cytoskeleton controlling cytoprotective enzyme genes, was also identified as another plausible target of the catechol type polyphenols by oxidative modification of the intracellular sulfhydryls. These results provide an alternative approach to understand that catechol type polyphenol is a potential modifier of redox-dependent cellular events through sulfhydryl modification.

DOI： 10.1021/tx900148k

Exogenous Proline and Glycinebetaine Suppress Apoplastic Flow to Reduce Na+ Uptake in Rice Seedlings Reviewed

Muhammad Abdus Sobahan, Carlos Raul Arias, Eiji Okuma, Yasuaki Shimoishi, Yoshimasa Nakamura, Yoshihiko Hirai, Izumi C. Mori, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 73 ( 9 ) 2037 - 2042 2009.9

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

The application of exogenous proline and glycinebetaine (betaine) confers salt tolerance on plants under salt stress. The effects of exogenous proline and betaine on apoplastic How in rice plants under saline conditions were investigated using trisodium-8-hydroxy-1,3,6-pyrenetrisulphonic acid (PTS), an apoplastic tracer. Rice plants took up more PTS under light conditions than under dark conditions. Salt stress increased PTS uptake and Na+ content of rice leaves, but did not affect K+ content, resulting in a lower K+/Na+ ratio. Addition of proline or betaine to the saline medium suppressed Na+-induced PTS uptake and Na+ accumulation, while the K+ content was slightly increased, which led to a high K+/Na+ ratio under saline conditions. These results suggest that exogenous proline and betaine suppressed Na+-enhanced apoplastic flow to reduce Na+ uptake in rice plants.

DOI： 10.1271/bbb.90244

Myrosinases, TGG1 and TGG2, Redundantly Function in ABA and MeJA Signaling in Arabidopsis Guard Cells Reviewed

Mohammad Mahbub Islam, Chiharu Tani, Megumi Watanabe-Sugimoto, Misugi Uraji, Md. Sarwar Jahan, Choji Masuda, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

PLANT AND CELL PHYSIOLOGY 50 ( 6 ) 1171 - 1175 2009.6

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Thioglucoside glucohydrolase (myrosinase), TGG1, is a strikingly abundant protein in Arabidopsis guard cells. We investigated responses of tgg1-3, tgg2-1 and tgg1-3 tgg2-1 mutants to abscisic acid (ABA) and methyl jasmonate (MeJA) to clarify whether two myrosinases, TGG1 and TGG2, function during stomatal closure. ABA, MeJA and H2O2 induced stomatal closure in wild type, tgg1-3 and tgg2-1, but failed to induce stomatal closure in tgg1-3 tgg2-1. All mutants and wild type showed Ca-2-induced stomatal closure and ABA-induced reactive oxygen species (ROS)production. A model is discussed in which two myrosinases redundantly function downstream of ROS production and upstream of cytosolic Ca-2 elevation in ABA and MeJA signaling in guard cells.

DOI： 10.1093/pcp/pcp066

Induction of Apoptosis by beta-Carotene and Dimethyl Tetrasulfide Assisted by UVA Irradiation in HL-60 Cells Reviewed

Gongliang Zhang, Haitao Wu, Beiwei Zhu, Yasuaki Shimoishi, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 73 ( 5 ) 1014 - 1020 2009.5

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Cellular phototoxicity induced by UVA irradiation and its potential application to therapy has been reported. In the present study, the induction of apoptosis induced by beta-carotene and dimethyl tetrasulfide (Me2S4) assisted by UVA irradiation in HL-60 cells was assessed. beta-carotene assisted by UVA significantly decreased the cell viability and induced DNA fragmentation in HL-60 cells. Me2S4 combined with beta-carotene and assisted by UVA significantly inhibited the cell viability, and enhanced the caspase-3 activity which was completely inhibited by N-acety-L-cysteine. beta-carotene was significantly degraded by UVA, but this was not accellerated by Me2S4 in a cell culture system. The photodegradation products of beta-carotene prepared by UVA irradiation regardless of the addition of Me2S4 showed lower cytotoxicity than beta-carotene itself in HL-60 cells. These results suggest that the ROS- and caspase-3-dependent apoptosis induced by beta-carotene and Me2S4 assisted by UVA was due to a synergistic action rather than to the sole effect of the photodegradation products of beta-carotene in HL-60 cells.

DOI： 10.1271/bbb.80794

(-)-Epigallocatechin-3-gallate induces up-regulation of Th1 and Th2 cytokine genes in Jurkat T cells Reviewed

Haitao Wu, Beiwei Zhu, Yasuaki Shimoishi, Yoshiyuki Murata, Yoshimasa Nakamura

ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 483 ( 1 ) 99 - 105 2009.3

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

In the present Study, we found that (-)-epigallocatechin-3-gallate (EGCG) significantly up-regulated the mRNA expression of the Th1/Th2 cytokines including IL-2, IFN-gamma, IL-5 and IL-13 in Jurkat T cells. The EGCG-induced mRNA Up-regulation of IL-2 and IL-5 was predominantly affected by the extracellular signal-regulated protein kinase (ERK) signalling, whereas IL-13 gene expression, the most responsive to the EGCG treatment, was dependent on neither ERK nor c-jun NH(2)-terminal kinase (JNK) signalling. IFN-gamma gene expression was partially mitigated by both inhibitors of the ERK and JNK pathways. Furthermore, catalase significantly attenuated the intracellular peroxide production, phosphorylation of ERK and JNK, and all cytokine gene expressions induced by EGCG. In addition, physiologically relevant concentrations of both EGCG and H(2)O(2)-induced up-regulation of IL-5 gene expression. Our findings provide biological evidence that EGCG induces Th1/Th2 cytokine mRNA expression via H(2)O(2). production followed by activation of ERK or JNK in Jurkat T cells. (C) 2008 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.abb.2008.12.010

Exogenous proline and glycinebetaine increase antioxidant enzyme activities and confer tolerance to cadmium stress in cultured tobacco cells Reviewed

Mohammad Muzahidul Islam, Anamul Hoque, Eiji Okuma, Mst. Nasrin, Akhter Banu, Yasuaki Shimoishi, Yoshimasa Nakamura, Yoshiyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 166 ( 15 ) 1587 - 1597 2009

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

Environmental stress, including heavy metal stress, can cause oxidative damage to plants. Up-regulation of the antioxidant defense system induced by proline and glycinebetaine (betaine) alleviates the damaging effects of oxidative stress in plants. Here, we investigated the protective effects of exogenously applied proline and betaine on growth, accumulation of proline and betaine, lipid peroxidation and activity of antioxidant enzymes in cultured tobacco Bright Yellow-2 (BY-2) cells exposed to cadmium (Cd) stress. Cadmium stress (at 100 mu M Cd) caused a significant inhibition of the growth of BY-2 cells, and both proline and betaine significantly mitigated this inhibition. In addition, the mitigating effect of proline was more pronounced than that of betaine. Cadmium stress leads to an accumulation of Cd and endogenous proline in cultured cells, increased lipid peroxidation and peroxidase (POX) activity, and decreased activity of superoxide dismutase (SOD) and catalase (CAT). Exogenous application of proline resulted in a decrease in lipid peroxidation and an increase in SOD and CAT activities without reducing Cd contents under Cd stress, while application of betaine resulted in a decrease in lipid peroxidation and an increase in CAT activity with reducing Cd accumulation. Furthermore, exogenous proline and betaine intensified the accumulation of proline and betaine in Cd-stressed BY-2 cells, respectively. The present study suggests that proline and betaine confer tolerance to Cd stress in tobacco BY-2 cells by different mechanisms. (C) 2009 Elsevier GrnbH. All rights reserved.

DOI： 10.1016/j.jplph.2009.04.002

Proline and glyclinebetaine induce antioxidant defense gene expression and suppress cell death in cultured tobacco cells under salt stress Reviewed

Nasrin Akhter Banu, Anamul Hoque, Megumi Watanabe-Sugimoto, Ken Matsuoka, Yoshimasa Nakamura, Yasuaki Shimoishi, Yoshlyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 166 ( 2 ) 146 - 156 2009

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

Salt stress causes oxidative damage and cell death in plants. Plants accumulate proline and glycinebetaine (betaine) to mitigate detrimental effects of salt stress. The aim of this study was to investigate the protective effects of proline and betaine on cell death in NaCl-unadapted tobacco (Nicotiana tabacum) Bright Yellow-2 suspension-cultured cells subjected to salt stress. Salt stress increased reactive oxygen species (ROS) accumulation, lipid peroxidation, nuclear deformation and degradation, chromatin condensation, apoptosis-tike cell death and ATP contents. Neither proline nor betaine affected apoptosis-like cell death and G, phase population, and increased ATP contents in the 200 mM NaCl-stressed cells. However, both of them effectively decreased ROS accumulation and lipid peroxidation, and suppressed nuclear deformation and chromatin condensation induced by severe salt stress. Evans Blue staining experiment showed that both proline and betaine significantly suppressed increment of membrane permeability induced by 200 mM NaCl. Furthermore, among the ROS scavenging antioxidant defense genes studied here, mRNA levels of salicylic acid-binding (SAbind) catalase (CAT) and lignin-forming peroxidase (POX) were found to be increased by proline and betaine under salt stress. It is concluded that both proline and betaine provide a protection against NaCl-induced cell death via decreasing level of ROS accumulation and lipid peroxidation as well as improvement of membrane integrity. (C) 2008 Elsevier GmbH. ALL rights reserved.

DOI： 10.1016/j.jplph.2008.03.002

Nitric oxide functions in both methyl jasmonate signaling and abscisic acid signaling in Arabidopsis guard cells Reviewed

Naoki Saito, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

Plant Signaling and Behavior 4 ( 2 ) 119 - 120 2009

Language：English Publishing type：Research paper (scientific journal) Publisher：Landes Bioscience

Intracellular components in methyl jasmonate (MeJA) signaling remain largely unknown, to compare those in well-understood abscisic acid (ABA) signaling. We have reported that nitric oxide (NO) is a signaling component in MeJA-induced stomatal closure, as well as ABA-induced stomatal closure in the previous study. To gain further information about the role of NO in the guard cell signaling, NO production was examined in an ABA- and MeJA-insensitive Arabidopsis mutant, rcn1. Neither MeJA nor ABA induced NO production in rcn1 guard cells. Our data suggest that NO functions downstream of the branch point of MeJA and ABA signaling in Arabidopsis guard cells. ©2009 Landes Bioscience.

DOI： 10.4161/psb.4.2.7537

Chemoprevention by Isothiocyanates: Molecular Basis of Apoptosis Induction Invited Reviewed

Yoshimasa Nakamura

FOOD FACTORS FOR HEALTH PROMOTION 61 170 - 181 2009

Authorship：Lead author,　Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：KARGER

An important and promising group of compounds that have a cancer-chemopreventive property are organosulfur compounds, such as isothiocyanates (ITCs). Various ITCs are effective chemoprotective agents against chemical carcinogenesis in experimental animals. Several epidemiological studies also indicated that the dietary consumption of ITCs or ITC-containing foods inversely correlates with the risk of developing lung, breast, and colon cancers, providing evidence that they have a potential to prevent cancer in humans. Mechanistically, ITCs are capable of inhibiting both the formation and development of a cancer cell through multiple pathways; i.e. the inhibition of carcinogen-activating cytochrome P450 mono-oxygenases, induction of carcinogen-detoxifying phase 2 enzymes, induction of apoptosis, and inhibition of cell cycle progression. We have clarified the molecular mechanisms underlying the relationship between cell cycle regulation and apoptosis induced by benzyl ITC (BITC), a major ITC compound isolated from papaya (Corica papaya) fruit. We identified phosphorylated Bcl-2 as a key molecule linking p38 MAPK-dependent cell cycle regulation with the c-Jun N-terminal kinase activation by BITC. We also established that BITC exerts the cytotoxic effect more preferentially in the proliferating cells than in the quiescent cells. Furthermore, p53 was found to be a potential negative regulator of apoptosis induction by BITC in normal epithelial cells through inhibition of cell cycle progression at the G(0)/G(1) phase. In contrast, treatment with an excessive concentration of BITC resulted in necrotic cell death in an ATP-dependent manner. This review addresses the biological impact of cell death induction by BITC as well as other ITCs and the involved molecules regulating signal pathways. Copyright (C) 2009 S. Karger AG, Basel

DOI： 10.1159/000212749

(-)-Epigallocatechin-3-gallate Potentiates the Cytotoxicity Induced by Benzyl Isothiocyanate and Hydrogen Peroxide in Human Jurkat T Lymphocytes Reviewed

Haitao Wu, Tomoko Yokoyama, Beiwei Zhu, Yasuaki Shimoishi, Yoshiyuki Murata, Yoshimasa Nakamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 72 ( 11 ) 3034 - 3037 2008.11

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

(-)-Epigallocatechin-3-gallate (EGCG)-induced apoptosis was along both the extracellular signal-regulated protein kinase (ERK) and c-jun N-terminal kinase (JNK) pathways in Jurkat cells. Co-treatment with EGCG potentiated the cytotoxicity induced by benzyl isothiocyanate (BITC) and H2O2, both being inhibited by ERK and JNK inhibitors. These results suggest the significant role of mitogen-activated protein kinase (MAPK) signaling in the apoptosis induction regulated by EGCG alone and in combination.

DOI： 10.1271/bbb.80422

Effect of Dimethyl Sulfides on the Induction of Apoptosis in Human Leukemia Jurkat Cells and HL-60 Cells Reviewed

Gongliang Zhang, Haitao Wu, Beiwei Zhu, Yasuaki Shimoishi, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 72 ( 11 ) 2966 - 2972 2008.11

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Organosulfur compounds have been established to possess anticancer effects. To provide a better understanding of the biological function of dimethyl sulfides, dimethyl monosulfide (Me2S), dimethyl disulfide (Me2S2), dimethyl trisulfide (Me2S3) and dimethyl tetrasulfide (Me2S4) were used as experimental materials to investigate their effects on apoptosis induction in human leukemia Jurkat cells and HL-60 cells. Treatment with 20 Km dimethyl sulfides for 24 h decreased the viability of both cells. The cell viability-reducing effect of these sulfides was in the following order: Me2S4 approximate to Me2S3 > Me2S2 approximate to Me2S for Jurkat cells and Me2S4 > Me2S3 > Me2S2 approximate to Me2S for HL-60 cells. Me2S3 and Me2S4 significantly induced DNA fragmentation and caspase-3 activation. The addition of GSH or NAC completely suppressed the sulfide-induced apoptosis. Our results indicate that dimethyl sulfides with a larger number of sulfur atoms more strongly induced apoptosis in both human leukemia cells via ROS production and caspase-3 activation.

DOI： 10.1271/bbb.80453

Deficient Glutathione in Guard Cells Facilitates Abscisic Acid-Induced Stomatal Closure but Does Not Affect Light-Induced Stomatal Opening Reviewed

Md. Sarwar Jahan, Ken'ichi Ogawa, Yoshimasa Nakamura, Yasuaki Shimoishi, Izumi C. Mori, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 72 ( 10 ) 2795 - 2798 2008.10

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

We investigated the role of glutathione (GSH) in stomatal movements using a GSH deficient mutant, chlorinal-1 (ch1-1). Guard cells of ch1-1 mutants accumulated less GSH than wild types did. Light induced stomatal opening in ch1-1 and wild-type plants. Abscisic acid (ABA) induced stomatal closure in ch1-1 mutants more than wild types without enhanced reactive oxygen species (ROS) production. Therefore, GSH functioned downstream of ROS production in the ABA signaling cascade.

DOI： 10.1271/bbb.80407

Roles of RCN1, regulatory a subunit of protein phosphatase 2A, in methyl jasmonate signaling and signal crosstalk between methyl jasmonate and abscisic acid Reviewed

Naoki Saito, Shintaro Munemasa, Yoshimasa Nakamura, Yasuaki Shimoishi, Izumi C. Mori, Yoshiyuki Murata

PLANT AND CELL PHYSIOLOGY 49 ( 9 ) 1396 - 1401 2008.9

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Methyl jasmonate (MeJA) as well as abscisic acid (ABA) induces stomatal closure with their signal crosstalk. We investigated the function of a regulatory A subunit of protein phosphatase 2A, RCN1, in MeJA signaling. Both MeJA and ABA failed to induce stomatal closure in Arabidopsis rcn1 knockout mutants unlike in wild-type plants. Neither MeJA nor ABA induced reactive oxygen species (ROS) production and suppressed inward-rectifying potassium channel activities in rcn1 mutants but not in wild-type plants. These results suggest that RCN1 functions upstream of ROS production and downstream of the branch point of MeJA signaling and ABA signaling in Arabidopsis guard cells.

DOI： 10.1093/pcp/pcn106

Structure-dependent photodegradation of carotenoids accelerated by dimethyl tetrasulfide under UVA irradiation Reviewed

Gongliang Zhang, Beiwei Zhu, Yoshimasa Nakamura, Yasuaki Shimoishi, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 72 ( 8 ) 2176 - 2183 2008.8

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Carotenoids are used in wide-ranging food applications, but they are susceptible to degradation by many factors including light. We examined the photodegradation of five kinds of carotenoids and three kinds of anthocyanins to clarify which structures of pigments were favorable to accelerated degradation by sulfides under UVA irradiation. Under UVA irradiation, crocetin and crocin were decomposed more rapidly in the presence of dimethyl tetrasulfide than in the absence of the sulfide, but not as rapidly as beta-carotene, zeaxanthin and beta-cryptoxanthin were. However, cyanidin was decomposed more slowly in the presence of sulfide than in the absence of sulfide. Moreover, the photodegradation of kuromanin and keracyanin was not affected by the addition of a sulfide. We also examined the mechanism for this accelerated degradation. Normal hexane was more favorable to the photodegradation of beta-carotene than methanol and ethanol. The accelerated degradation was inhibited by free radical scavengers, but enhanced by the addition of deuterium oxide. These results suggest that conjugated double bonds were favorable to the accelerated photodegradation by sulfide and that this reaction was mediated by free radicals.

DOI： 10.1271/bbb.80251

Galloylated catechins as potent inhibitors of hypochlorous acid-induced DNA damage Reviewed

Yoshichika Kawai, Yuri Matsui, Hajime Kondo, Hiroshi Morinaga, Koji Uchida, Noriyuki Miyoshi, Yoshimasa Nakamura, Toshihiko Osawa

CHEMICAL RESEARCH IN TOXICOLOGY 21 ( 7 ) 1407 - 1414 2008.7

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Hypochlorous acid (HOC1), a strong oxidant derived from myeloperoxidase in neutrophils and macrophages, can chlorinate DNA bases at the site of inflammation. Because little is known about the protective role of natural antioxidants, such as polyphenols, for the myeloperoxidase-derived DNA damage, we screened the inhibitory effects of various phenolic antioxidants on the chlorination of the 2'-deoxycytidine residue by HOC1 in vitro and found that green tea catechins, especially (-)-epicatechin gallate (ECg) and (-)-epigallocatechin gallate (EGCg), significantly inhibited the chlorination. These catechins also reduced nucleoside- and taurine-chloramines, which can induce secondary oxidative damage, into their native forms. Mass spectrometric and nuclear magnetic resonance analyses showed that ECg and EGCg can effectively scavenge HOC1 and/or chloramine species resulting in the formation of mono-and dichlorinated ECg and EGCg. Using the HL-60 human leukemia cell line, it was found that ECg could efficiently accumulate in the cells. Immunocytometric analyses using antihalogenated 2'-deoxycytidine antibody showed that pretreatment of cells with ECg inhibited the HOC1-induced immunofluorescence. In addition, the chlorinated ECg derivatives were detected in the HOC1-treated HL-60 cells. These results showed that green tea catechins, especially 3-galloylated catechins, may be the plausible candidate for the prevention of inflammation-derived DNA damage and perhaps carcinogenesis.

DOI： 10.1021/tx800069e

Proline and glycinebetaine enhance antioxidant defense and methylglyoxal detoxification systems and reduce NaCl-induced damage in cultured tobacco cells Reviewed

Md. Anamul Hoque, Mst. Nasrin Akhter Banu, Yoshimasa Nakamura, Yasuaki Shimoishi, Yoshiyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 165 ( 8 ) 813 - 824 2008

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

Salt stress impairs reactive oxygen species (ROS) and methylglyoxal (MG) detoxification systems, and causes oxidative damage to plants. Up-regulation of the antioxidant and glyoxalase systems provides protection against NaCl-induced oxidative damage in plants. Thiol-disulfide contents, glutathione content and its associated enzyme activities involved in the antioxidant defense and glyoxalase systems, and protein carbonylation in tobacco Bright Yellow-2 cells grown in suspension culture were investigated to assess the protection offered by proline and glycinebetaine against salt stress. Salt stress increased protein carbonylation, contents of thiol, disulfide, reduced (GSH) and oxidized (GSSG) forms of glutathione, and the activity of glutathione-S-transferase and glyoxalase II enzymes, but decreased redox state of both thiol-disulfide and glutathione, and the activity of glutathione peroxidase and glyoxalase I enzymes involved in the ROS and MG detoxification systems. Exogenous application of proline or glycinebetaine resulted in a reduction of protein carbonylation, and in an increase in glutathione redox state and activity of glutathione peroxidase, glutathione-S-transferase and glyoxalase I under salt stress. Neither proline noi glycinebetaine, however, had any direct protective effect on NaCl-induced GSII-associated enzyme activities. The present study, therefore, suggests that both proline and glycinebetaine provide a protective action against NaCl-induced oxidative damage by reducing protein carbonylation, and enhancing antioxidant defense and MG detoxification systems. (C) 2007 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.jplph.2007.07.013

Exogenous proline and glycinebetaine increase NaCl-induced a scorbate-glutathione cycle enzyme activities, and proline improves salt tolerance more than glycinebetaine in tobacco Bright Yellow-2 suspension-cu ltured cells Reviewed

Md. Anamul Hoque, Mst. Nasrin Akhter Banu, Eiji Okuma, Yoshiyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 164 ( 11 ) 1457 - 1468 2007.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

Up-regulation of the antioxidant system provides protection against NaCl-induced oxidative damage in plants. Antioxidants and activity of enzymes involved in the ascorbate-glutathione (ASC-GSH) cycle in tobacco Bright Yellow-2 (BY-2) were investigated to assess the antioxidant protection offered by exogenous proline and glycinebetaine (betaine from now on) against salt stress using cells grown in suspension culture. Reduced ascorbate (ASC) was detected in BY-2 cells but dehydroascorbate (DHA) was not. Large quantities of a reduced form of glutathione (GSH) and smaller quantities of an oxidized form of glutathione (GSSG) were detected in BY-2 cells. Salt stress significantly reduced the contents of ASC and GSH as well. as activities of ASC-GSH cycle enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR). Exogenous proline or betaine increased the activities of all enzymes except MDHAR involved in NaCl-induced ASC-GSH cycle. Levels of ASC and GSH in BY-2 cells under salt stress were lower in the presence of proline or betaine than in the absence of proline or betaine whereas there was no difference in redox status. Proline proved more effective than betaine in maintaining the activity of enzymes involved in NaCl-induced ASC-GSH cycle. Neither proline nor betaine had any direct protective effect on NaCl-induced enzyme activity involved in the antioxidant system; however, both improved salt tolerance by increasing enzyme activity. The present study, together with our earlier findings [Hoque MA, Okuma E, Banu MNA, Nakamura Y, Shimoishi Y, Murata Y. Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities. J Plant Physiol 2006;164:553-61.], suggests that proline offered greater protection against salt stress than betaine did because proline was more effective in increasing the activity of enzymes involved in the antioxidant system. (C) 2006 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.jplph.2006.10.004

Dietary flavonoid apigenin is a potential inducer of intracellular oxidative stress: The role in the interruptive apoptotic signal Reviewed

Noriyuki Miyoshi, Kisa Naniwa, Takayo Yamada, Toshihiko Osawa, Yoshimasa Nakamura

ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 466 ( 2 ) 274 - 282 2007.10

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE INC

Apigenin is a representative dietary flavone (2-phenyl-4H-1-benzopyran-4-one) inhibiting cancer cell growth both in cell culture systems and in vivo. The prooxidant potential of apigenin was confirmed by the observations using flowcytometric and irnmunoblotting techniques that the intracellular accumulations of reactive oxygen species (ROS) and protein carbonyls were detected in the cells treated, with apigenin in a dose-dependent manner. Conversely, chrysin (5,7-dihydroxyflavone) did not show any prooxidant effect. A structure-activity relationship data thus indicated that a 4'-monohydroxyl group, which can be oxidized to semiquinone radical but not up to quinone-like metabolite, is essential for prooxidant effect. When HL-60 cells were treated with not only a heme synthesis inhibitor succinyl acetone (SA) but also myeloperoxidase (MPO) inhibitors, the ROS level enhanced by apigenin was significantly reduced. The gathered data suggested that peroxidase-catalyzed production of apigenin B-ring phenoxyl radicals might be responsible for the prooxidant effect. This is supported by the observation that MPO is able to catalyze production of apigenin phenoxyl radicals, detected by an electron spin resonance-spin trapping technique. We also reveal that both SA and a-tocopherol enhance cellular susceptibility to apoptosis-inducing stimuli by apigenin. In conclusion, the prooxidant effect of apigenin is likely to oxidize a variety of thiols through the formation of phenoxyl radicals and thus seems to play a significant role in the abortive apoptotic pathway switching to necrotic cell death. (c) 2007 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.abb.2007.07.026

Exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine by increasing antioxidant enzyme activities Reviewed

Md. Anamul Hoque, Eiji Okuma, Mst. Nasrin Akhter Banu, Yoshimasa Nakamura, Yasuaki Shimoishi, Yoshiyuki Murata

JOURNAL OF PLANT PHYSIOLOGY 164 ( 5 ) 553 - 561 2007.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER GMBH, URBAN & FISCHER VERLAG

Proline and betaine accumulate in plant cells under environmental stresses including stress. Here, we investigated effects of proline and betaine on the growth and activities of antioxidant enzymes in tobacco Bright Yellow-2 (BY-2) culture cells in suspension under salt stress. Both proline and betaine mitigated the inhibition of growth of BY-2 cells under salt stress and the mitigating effect of proline was more than that of betaine. Salt stress significantly decreased the activities of superoxide dismutase (SOD), catalase and peroxidase in BY-2 cells. Exogenous application of proline or betaine alleviated the reduction in catalase and peroxidase activities but not SOD activity under salt stress. In addition, proline was found to be effective in alleviating the inhibition of salt stress-induced catalase and peroxidase activities in BY-2 cells. Neither proline nor betaine directly scavenged superoxide (02) or hydrogen peroxide (H2O2). It is concluded that exogenous proline mitigates the detrimental effects of salt stress more than exogenous betaine because of its superior ability to increase the activities of antioxidant enzymes. (C) 2006 Elsevier GmbH. All rights reserved.

DOI： 10.1016/j.jplph.2006.03.010

Detection of modified tyrosines as an inflammation marker in a photo-aged skin model Reviewed

Yukiko Ishitsuka, Fumio Maniwa, Chiharu Koide, Natsuko Douzaki, Yoji Kato, Yoshimasa Nakamura, Toshihiko Osawa

PHOTOCHEMISTRY AND PHOTOBIOLOGY 83 ( 3 ) 698 - 705 2007.5

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC PHOTOBIOLOGY

Reactive nitrogen species, produced during the process of inflammation induced by various factors including UV radiation, modify amino acids in crucial proteins. It is assumed that skin tissue is more likely to be modified, as it is located at the outer layer of a body that is exposed to UV radiation on a daily basis. To investigate the influence of the modified tyrosine on UV-exposed skin, we detected the nitrotyrosine or halogenated tyrosine and dityrosine in photo-aged model mice. The back skin of mice was exposed to a dose of 10 J cm(-2) day(-1) every day for 15 weeks. Samples exhibiting typical symptoms of photo aging were provided to the immunofluorescence study. The quantification of modified proteins was accomplished through a chemical analytical method known as HPLC-tandem mass spectrometry. Analysis of the irradiated skin samples showed that all modified tyrosine except nitrotyrosine demonstrated statistically significant increases. The molecular weights of major modified proteins, confirmed as 25-50 kDa, were measured using Western blot analysis with an anti-nitrotyrosine antibody. Furthermore, the immunofluorescence study verified that the localization of myeloperoxidase conformed to that of nitrotyrosine. This result suggests that the modified tyrosine was produced during the process of inflammation by UV irradiation. In this study, we used a low dose of UV irradiation to which we are exposed in daily life. Our results suggest that UV exposure in daily life may induce the production of modified tyrosines and skin aging.

DOI： 10.1562/2006-07-24-RA-978

The coronatine-insensitive 1 mutation reveals the hormonal signaling interaction between abscisic acid and methyl jasmonate in arabidopsis guard cells. Specific impairment of ion channel activation and second messenger production Reviewed

Shintaro Munemasa, Kenji Oda, Megumi Watanabe-Sugimoto, Yoshimasa Nakamura, Yasuaki Shimoishi, Yoshiyuki Murata

PLANT PHYSIOLOGY 143 ( 3 ) 1398 - 1407 2007.3

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC PLANT BIOLOGISTS

Methyl jasmonate (MeJA) elicits stomatal closing similar to abscisic acid (ABA), but whether the two compounds use similar or different signaling mechanisms in guard cells remains to be clarified. We investigated the effects of MeJA and ABA on second messenger production and ion channel activation in guard cells of wild-type Arabidopsis ( Arabidopsis thaliana) and MeJA-insensitive coronatine-insensitive 1 (coi1) mutants. The coi1 mutation impaired MeJA-induced stomatal closing but not ABA-induced stomatal closing. MeJA as well as ABA induced production of reactive oxygen species (ROS) and nitric oxide (NO) in wild-type guard cells, whereas MeJA did not induce production of ROS and NO in coi1 guard cells. The experiments using an inhibitor and scavengers demonstrated that both ROS and NO are involved in MeJA-induced stomatal closing as well as ABA-induced stomatal closing. Not only ABA but also MeJA activated slow anion channels and Ca2+ permeable cation channels in the plasma membrane of wild-type guard cell protoplasts. However, in coi1 guard cell protoplasts, MeJA did not elicit either slow anion currents or Ca2+ permeable cation currents, but ABA activated both types of ion channels. Furthermore, to elucidate signaling interaction between ABA and MeJA in guard cells, we examined MeJA signaling in ABA-insensitive mutant ABA-insensitive 2 (abi2-1), whose ABA signal transduction cascade has some disruption downstream of ROS production and NO production. MeJA also did not induce stomatal closing but stimulated production of ROS and NO in abi2-1. These results suggest that MeJA triggers stomatal closing via a receptor distinct from the ABA receptor and that the coi1 mutation disrupts MeJA signaling upstream of the blanch point of ABA signaling and MeJA signaling in Arabidopsis guard cells.

DOI： 10.1104/pp.106.091298

Expression and Ca2+ dependency of plasma membrane K+ channels of tobacco suspension cells adapted to salt stress Reviewed

Naoki Kasukabe, Megumi Watanabe-Sugimoto, Ken Matsuoka, Eiji Okuma, Ichiro Obi, Yoshimasa Nakamura, Yasuaki Shimoishi, Yoshiyuki Murata, Tadaaki Kakutani

PLANT AND CELL PHYSIOLOGY 47 ( 12 ) 1674 - 1677 2006.12

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

The expression of plasma membrane K+ channels of NaCl-adapted tobacco suspension cells and effects of extracellular Ca2+ on plasma membrane K+ channels were investigated. Reverse transcription-PCR (RT-PCR) analysis showed that expression of TORK1, which encodes a K+ channel, was much lower in NaCl-adapted cells than in NaCl-unadapted cells. The magnitude of the outward K+ currents of NaCl-adapted as well as NaCl-unadapted cells decreased with increasing extracellular Ca2+ but there is no significant difference in Ca2+ dependency of the K+ current. These analyses suggest that reduction of the number of K+ channels might cause NaCl adaptation of cells through the decrease of outward K+ currents.

DOI： 10.1093/pcp/pcl030

A novel labdane-type trialdehyde from Myoga (Zingiber mioga Roscoe) that potently inhibits human platelet aggregation and human 5-lipoxygenase Reviewed

Masako Abe, Yoshio Ozawa, Yasushi Uda, Yasujiro Morimitsu, Yoshimasa Nakamura, Toshihiko Osawa

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 70 ( 10 ) 2494 - 2500 2006.10

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

We screened myoga extracts for inhibitors of human platelet aggregation and human 5-lipoxygenase. We identified a novel labdane type of diterpene, together with three known diterpenes (miogadial and galanals A and B) from the flower buds of myoga. Spectroscopic data indicated the structure of the new compound to be 12(E)-labdene-15,16,(8 beta)17-trial (miogatrial). Miogatrial and miogadial were potent inhibitors of human platelet aggregation and human 5-lipoxygenase (5-LOX). The sesquiterpene, polygodial, also exhibited strong inhibitory activity against human platelet aggregation and 5-LOX. On the other hand, galanals A and B did not have inhibitory activity in either experimental system. It thus appears that a 3-formyl-3-butenal structure was essential for the potent inhibition of human platelet aggregation and human 5-LOX.

DOI： 10.1271/bbb.60226

Cell death induction by isothiocyanates and their underlying molecular mechanisms Invited Reviewed

Yoshimasa Nakamura, Noriyuki Miyoshi

BIOFACTORS 26 ( 2 ) 123 - 134 2006

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IOS PRESS

An important and promising group of compounds that have a chemopreventive property are organosulfur compounds, such as isothiocyanates (ITCs). In recent years, it has been shown that ITCs induce apoptosis in various cancer cell lines and experimental rodents. During the course of apoptosis induction by ITC, multiple signal-transduction pathways and apoptosis intermediates are modulated. We have also clarified the molecular mechanism underlying the relationship between cell cycle arrest and apoptosis induced by benzyl isothiocyanate ( BITC), a major ITC compound isolated from papaya. The exposure of cells to BITC resulted in the inhibition of the G(2)/M progression that coincided with not only the up-regulated expression of the G(2)/M cell cycle arrest-regulating genes but also the apoptosis induction. The experiment using the phase-specific synchronized cells demonstrated that the G(2)/M phase-arrested cells are more sensitive to undergoing apoptotic stimulation by BITC than the cells in other phases. We identified the phosphorylated Bcl-2 as a key molecule linking the p38 MAPK-dependent cell cycle arrest with the JNK activation by BITC. We also found that BITC induced the cytotoxic effect more preferentially in the proliferating normal human colon epithelial cells than in the quiescent cells. Conversely, treatment with an excessive concentration of BITC resulted in necrotic cell death without DNA ladder formation. This review addresses the biological impact of cell death induction by BITC as well as other ITCs and the involved signal transduction pathways.

DOI： 10.1002/biof.5520260203

Dietary isothiocyanates modify mitochondrial functions through their electrophilic reaction Reviewed

M Kawakami, N Harada, M Hiratsuka, K Kawai, Y Nakamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 69 ( 12 ) 2439 - 2444 2005.12

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

We found that both benzyl isothiocyanate (ITC) and phenyl ITC inhibited respiration in the mitochondria in an electrophilic reaction-dependent manner. ITG induced mitochondrial swelling and cytochrome c release were prevented by cyclosporin A, indicating that they are mediated through the ITC moiety-dependent reaction to critical thiol groups for the opening of membrane permeability transition-dependent pores.

DOI： 10.1271/bbb.69.2439

A fermented grain food product extract ameliorates tumor promoter-induced skin oxidative stress Reviewed

Y Nakamura, T Osawa

FOOD SCIENCE AND TECHNOLOGY RESEARCH 11 ( 4 ) 373 - 375 2005.12

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：KARGER

We demonstrated that a dietary supplement, Antioxidant Biofactor (AOB (R)), a fermented grain food, inhibits phorbol ester (TPA)-induced inflammatory responses. Pretreatment of mouse skin with ethyl acetate extract of AOB (0.5 mg) significantly attenuated the hydrogen peroxide level in mouse skin without inhibition of edema formation. Also, exposure of AOB extract to differentiated HL-60 cells resulted in dose-dependent inhibition of TPA-induced superoxide generation, which was stronger than those of the raw materials of AOB. Our results suggest that AOB is effective for prevention of skin oxidative stress.

DOI： 10.3136/fstr.11.373

alpha-Tocopherol-mediated caspase-3 up-regulation enhances susceptibility to apoptotic stimuli Reviewed

N Miyoshi, K Naniwa, T Kumagai, K Uchida, T Osawa, Y Nakamura

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 334 ( 2 ) 466 - 473 2005.8

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

Although alpha-tocopherol is known as an essential micronutrient involved in various oxidative stress-related processes, its non-antioxidant activities have only been characterized in recent years. In this study, we reveal that (+)-alpha-tocopherol [RRR-alpha-tocopherol] enhances cellular susceptibility to both oxidative and non-oxidative apoptosis-inducing stimuli through up-regulation of caspase-3/ CPP32 expression in several human cell lines. Exposure of (+)-alpha-tocopherol pretreated cells to known apoptosis-inducing stimuli, such as Fas, H2O2, or etoposide, resulted in an increase in cellular apoptotsis. In addition, (+)-alpha-tocopherol also elevated the procaspase-3 protein level and mRNA expression in a time- and dose-dependent manner, while other tocopherol analogues showed no effect. Experiments using a GC-specific DNA binding agent, mithramycin A, and an electrophoretic mobility shift assay demonstrated that Sp1 might mediate the enhanced expression of caspase-3. Our results also confirmed that (+)-a-tocopherol promotes the expression, but not the activation, of caspase-3 in various human cell lines. These findings provide biological evidence showing that (+)-alpha-tocopherol can amplify the apoptotic response by up-regulating the expression of pro-caspase-3. (c) 2005 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2005.06.113

Antioxidative catechol lignans converted from sesamin and sesaminol triglucoside by culturing with Aspergillus Reviewed

Y Miyake, S Fukumoto, M Okada, K Sakaida, Y Nakamura, T Osawa

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 53 ( 1 ) 22 - 27 2005.1

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Sesamin and sesaminol triglucoside in sesame seeds are major lignans that display an abundance of biological activities. Although their antioxidative activity in vitro is weak, they have been reported to suppress oxidative stress in vivo. We investigated the production of new antioxidative lignans from sesame lignans by culturing with the genus Aspergillus to enhance the function of food materials. Media containing sesamin or sesaminol triglucoside increased antioxidative activity for DPPH radical scavenging by culturing with Aspergillus usamii mut. shirousamii RIB2503. The antioxidative lignans in sesamin medium were identified as sesamin 2,6-dicatechol and episesamin 2,6-dicatechol. Those in sesaminol triglucoside medium were identified as sesaminol 6-catechol and episesaminol 6-catechol, which are novel antioxidative lignans. It is suggested that they may exhibit higher antioxidative activity than sesamin and sesaminol triglucoside because they have the catechol functional moiety.

DOI： 10.1021/jf048043h

Endogenous formation of novel halogenated 2 '-deoxycytidine - Hypohalous acid-mediated DNA modification at the site of inflammation Reviewed

Y Kawai, H Morinaga, H Kondo, N Miyoshi, Y Nakamura, K Uchida, T Osawa

JOURNAL OF BIOLOGICAL CHEMISTRY 279 ( 49 ) 51241 - 51249 2004.12

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

A potential role of DNA damage by leukocyte-derived reactive species in carcinogenesis has been suggested. Leukocyte-derived peroxidases, such as myeloperoxidase and eosinophil peroxidase, use hydrogen peroxide and halides (Cl- and Br-) to generate hypohalous acids (HOCl and HOBr), halogenating intermediates. It has been suggested that these oxidants lead to the formation of halogenated products upon reaction with nucleobases. To verify the consequences of phagocyte-mediated DNA damage at the site of inflammation, we developed a novel monoclonal antibody (mAb2D3) that recognizes the hypohalous acid-modified DNA and found that the antibody most significantly recognized HOCl/HOBr-modified 2'-deoxycytidine residues. The immunoreactivity of HOCl-treated oligonucleotide was attenuated by excess methionine, suggesting that chloramine-like species may be the plausible epitopes of the antibody. On the basis of further characterization combined with mass spectrometric analysis, the epitopes of mAb2D3 were determined to be novel N-4,5-dihalogenated 2'-deoxycytidine residues. The formation of the dihalogenated 2'-deoxycytidine in vivo was immunohistochemically demonstrated in the lung and liver nuclei of mice treated with lipopolysaccharides, an experimental inflammatory model. These results strongly suggest that phagocyte-derived oxidants, hypohalous acids, endogenously generate the halogenated DNA bases such as a novel dihalogenated 2'-deoxycytidine in vivo. Halogenation ( chlorination and/or bromination) of DNA therefore may constitute one mechanism for oxidative DNA damage at the site of inflammation.

DOI： 10.1074/jbc.M408210200

Zerumbone, a tropical ginger sesquiterpene, activates phase II drug metabolizing enzymes Reviewed

Y Nakamura, C Yoshida, A Murakami, H Ohigashi, T Osawa, K Uchida

FEBS LETTERS 572 ( 1-3 ) 245 - 250 2004.8

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Zerumbone (ZER), a sesquiterpene compound occurring in tropical ginger Zingiber zerumbet Smith, has been implicated as one of the promising chemopreventive agents against colon and skin cancer. In the present study, we investigated the phase II detoxification enzymes induction of ZER using a cultured rat normal liver epithelial cell line. Exposure of RL34 cells to ZER resulted in the significant induction of glutathione S-transferase, while the reduced analogues of ZER (alpha-humulene and 8-hydroxy-alpha-humulene) did not show any inducing effect. Therefore, the electrophilic property, characterized by the reactivity with intracellular nucleophiles including protein sulfhydryls as well as low molecular weight thiols, at the 8-position alpha, beta-unsaturated carbonyl group plays an important role in the induction of phase II enzymes. ZER induced nuclear localization of the transcription factor Nrf2 that binds to antioxidant response element (ARE) of the phase II enzyme genes, suggesting that ZER is a potential activator of the Nrf2/ARE-dependent detoxification pathway. This is consistent with the observation that ZER potentiated the gene expression of several Nrf2/ARE-dependent phase II enzyme genes, including gamma-glutamylcysteine synthetase, glutathione peroxidase, and hemeoxygenase-1. The present study also implied the antioxidant role of this detoxification system activation by ZER in the neutralization of lipid peroxidation in hepatocytes, providing a new insight for cancer prevention. (C) 2004 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.

DOI： 10.1016/j.febslet.2004.07.042

Antimicrobial activities of diterpene dialdehydes, constituents from myoga (Zingiber mioga Roscoe), and their quantitative analysis Reviewed

M Abe, Y Ozawa, Y Uda, F Yamada, Y Morimitsu, Y Nakamura, T Osawa

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 68 ( 7 ) 1601 - 1604 2004.7

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

The antimicrobial activities of the three diterpene dialdehydes, miogadial, galanal A and galanal B, isolated from flower buds of the myoga (Zingiber mioga Roscoe) plant were investigated with some strains of bacteria, yeasts and molds. Among the three compounds, miogadial exhibited relatively greater antimicrobial activity than the others against Gram-positive bacteria and yeasts. Galanals A and B also behaved as antimicrobial agents against Gram-positive bacteria and yeasts. The content of miogadial in the flower buds was much higher than that in the leaves, whereas galanals A and B were contained at high levels in the leaves and rhizomes.

DOI： 10.1271/bbb.68.1601

Zerumbone, a sesquiterpene in subtropical ginger, suppresses skin tumor initiation and promotion stages in ICR mice Reviewed

A Murakami, T Tanaka, JY Lee, YJ Surh, HW Kim, K Kawabata, Y Nakamura, S Jiwajinda, H Ohigashi

INTERNATIONAL JOURNAL OF CANCER 110 ( 4 ) 481 - 490 2004.7

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-LISS

We recently showed that zerumbone, a sesquiterpene found in subtropical ginger, suppresses colonic tumor marker formation in rats and induces apoptosis in colon cancer cell lines. In our present study, the anti-tumor initiating and promoting activities of zerumbone in mouse skin were evaluated using a conventional 2-stage carcinogenesis model. A single topical pretreatment to mouse skin (2 mumol) 24 hr before application of dimethylbenz[a]anthracene (0.2 mumol) markedly suppressed tumor incidence by 60% and the number of tumors by 80% per mouse. Repeated pretreatment (16 nmol) twice weekly during the post-initiation phase reduced the number of 12-O-tetradecanoylphorbol-13-acetate (TPA, 1.6 nmol)-induced tumors by 83% as well as their diameter by 57%. Multiple reverse transcriptase (RT) PCR experiments revealed that zerumbone (2 mumol) enhanced the mRNA expression level of manganese superoxide dismutase, glutathione peroxidase-1, glutathione S-transferase-P1 and NAD(P)H quinone oxidoreductase in the epidermis, but not that of cytochrome P450 1A1 or 1B1. Further, it diminished TPA-induced cyclooxygenase-2 protein expression and phosphorylation of extracellular signal-regulated kinase 1/2, while pretreatment(s), in either the priming or activation stage or both, reduced double TPA application-induced hydrogen peroxide formation and edema induction by 29% to 86%, respectively. Histologic examination revealed that pretreatment(s) with zerumbone suppressed leukocyte infiltration and reduced proliferating cell nuclear antigen-labeling indices. Together, our results indicate that zerumbone is a promising agent for the prevention of both tumor initiating and promoting processes, through induction of anti-oxidative and phase II drug metabolizing enzymes as well as attenuation of proinflammatory signaling pathways. (C) 2004 Wiley-Liss, Inc.

DOI： 10.1002/ijc.20175

Extract of vinegar "Kurosu" from unpolished rice inhibits the proliferation of human cancer cells Reviewed

K Nanda, N Miyoshi, Y Nakamura, Y Shimoji, Y Tamura, Y Nishikawa, K Uenakai, H Kohno, T Tanaka

JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH 23 ( 1 ) 69 - 75 2004.3

Language：English Publishing type：Research paper (scientific journal) Publisher：APSIT ASSOC PROM STUD IMMUNOL TUMOR

The effects of the ethyl acetate extract of "Kurosu" (EK), Japanese traditional vinegar from unpolished rice, on the proliferation of a variety of human cancer cell lines were investigated by using the alamar blue assay. Cancer cell lines included colon adenocarcinoma (Caco-2), lung carcinoma (A549), breast adenocarcinoma (MCF-7), bladder carcinoma (5637), and prostate carcinoma (LNCaP) cells. EK inhibited the proliferation of all tested cell lines in a dose-dependent manner, with inhibition mostly pronounced in Caco-2 cells (up to 62% inhibition at a dose level of 0.025%). Flow cytometry of EK-treated Caco-2 cells showed a decrease in cell number in the G(2)/M phase and an increase in the sub-G(1) phase (apoptotic). In addition, DNA fragmentation was detected in Caco-2 cells cultured with EK by immunostaining. RT-PCR analysis revealed p21 mRNA expression was induced in EK-treated Caco-2 cells. Moreover, PARP cleavage was promoted in EK-treated Caco-2 cells. These results Suggest that EK causes G(0)/G(1) arrest through p21 induction and, thus, is a potential apoptosis inducer in Caco-2 cells.

Benzyl isothiocyanate modifies expression of the G(2)/M arrest-related genes Reviewed

N Miyoshi, K Uchida, T Osawa, Y Nakamura

BIOFACTORS 21 ( 1-4 ) 23 - 26 2004

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IOS PRESS

Naturally occurring isothiocyanates are effective chemoprotective agents against chemical carcinogenesis in experimental animals. In the present study, we clarified the molecular mechanism underlying the relationship between benzyl isothiocyanate (BITC)-induced cell cycle arrest and apoptosis. The exposure of HL-60 cells to BITC resulted in the inhibition of the G(2)/M progression that coincided with the apoptosis induction. We demonstrated that BITC significantly up-regulated expression of the G(2)/M cell cycle arrest-regulating genes including p21, GADD45, and 14-3-3sigma. Thus, these gathered data further supported that BITC has a potential to induce apoptosis selectively in the proliferating pre-cancerous cells through a cell cycle arrest-dependent mechanism.

Benzyl isothiocyanate inhibits oxidative stress in mouse skin: Involvement of attenuation of leukocyte infiltration Invited Reviewed

Y Nakamura, N Miyoshi, S Takabayashi, T Osawa

BIOFACTORS 21 ( 1-4 ) 255 - 257 2004

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：IOS PRESS

The exposure of benzyl isothiocyanate (BITC) to mouse skin resulted in the attenuation of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced oxidative damage through not only inhibition of the NADPH oxidase system but also leukocyte clearance at inflamed region. In spite of little ability to affect TPA-induced edema formation, pretreatments of mouse skin with BITC before the first or second TPA treatment significantly decrease the H2O2 level. A histological study also demonstrated that BITC enhanced the terminal deoxynucleotidyl transferase-dUTP nick end labeling (TUNEL)-positive index in mouse skin, suggesting that BITC might accelerate the disappearance of infiltrated leukocytes. Thus, these gathered data further supported that BITC has a potential as an anti-inflammatory agent.

Dietary ginger constituents, galanals A and B, are potent apoptosis inducers in Human T lymphoma Jurkat cells Reviewed

N Miyoshi, Y Nakamura, Y Ueda, M Abe, Y Ozawa, K Uchida, T Osawa

CANCER LETTERS 199 ( 2 ) 113 - 119 2003.9

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI IRELAND LTD

The effects of the constituents isolated from ginger species including curcumin, 6-gingerol and labdane-type diterpene compounds on cell proliferation and the induction of apoptosis in the cultured human T lymphoma Jurkat cells were studied. Among the tested compounds, Galanals A and 13, isolated from the flower buds of a Japanese ginger, myoga (Zingiber mioga Roscoe), showed the most potent cytotoxic effect. Exposure Of Jurkat human T-cell leukemia cells to galanals resulted in the induction of apoptotic cell death characterized by DNA fragmentation and caspase-3 activation. The mitochondrial damage pathway was suggested to be involved in galanal-induced apoptosis because the treatment of cells with galanals induced mitochondrial transmembrane potential (Deltapsim) alteration and cytochrome c release. The anti-apoptotic Bcl-2 protein was downregulated by the galanal treatment together with enhancement of the Bax expression. In conclusion, the results from this study provide biological evidence that ginger-specific constituents other than curcuminoids are potential anticancer agents. (C) 2003 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/S0304-3835(03)00381-1

Correlation of antimutagenic activity and suppression of CYP1A with the lipophilicity of alkyl gallates and other phenolic compounds Reviewed

Q Feng, T Kumagai, Y Nakamura, K Uchida, T Osawa

MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 537 ( 1 ) 101 - 108 2003.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Alkyl gallates are widely used as food antioxidants. Methyl, ethyl, propyl, lauryl, and cetyl gallates showed antimuta-genicity to activated 2-aminoanthracene (2AA)-induced SOS responses in Salmonella typhimurium TA1535/pSK1002. They also exhibited a suppressive effect on 3-methylcholanthrene (3-MC)-induced cytochrome P450 1A (CYP1A) in human hepatoma HepG2 cells, as indexed by the 7-ethoxyresorufin-O-deethylase (EROD) activity, and on CYP1A protein level. Both antimutagenicity and suppression of CYP1A appeared to be dependent on alkyl chain lengths, which suggested lipophilicity dependence. Based on those results, we investigated 26 other phenolic compounds for their lipophilicity, antimutagenicity and inhibition of EROD activity. The lipophilicity correlated well with the inhibition of EROD activity (r = 0.78), and the inhibition of EROD activity correlated with the antimutagenicity of those compounds (r = 0.71). The results suggest that the lipophilicity of the phenolic compounds may be an important factor in their ability to inhibit EROD activity. (C) 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S1383-5718(03)00057-3

Dihydrochalcones: Evaluation as novel radical scavenging antioxidants Reviewed

Y Nakamura, S Watanabe, N Miyake, H Kohno, T Osawa

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 51 ( 11 ) 3309 - 3312 2003.5

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Dihydrochalcones are a family of bicyclic flavonoids, defined by the presence of two benzene rings joined by a saturated three carbon bridge. In the present study, we systematically examined the antioxidant activities of dihydrochalcones against the stable free radical (1,1-diphenyl-2-picrylhydrazyl) and lipid peroxidation in the erythrocyte membrane. All dihydrochalcones exhibited higher antioxidant activities than the corresponding flavanones. The H-1 NMR analysis indicated that the active dihydrochalcone has a time-averaged conformation in which the aromatic A ring is orthogonal to the carbonyl group, while the inactive dihydrochalcone such as 2'-O-methyl-phloretin has a strongly hydrogen-bonded phenolic hydroxyl group, suggestive of a coplanar conformation. A hydroxyl group at the 2'-position of the dihydrochalcone A ring, newly formed by reduction of the flavanone C ring, is an essential pharmacophore for its radical scavenging potential.

DOI： 10.1021/jf0341060

Structures of (-)-epicatechin glucuronide identified from plasma and urine after oral ingestion of (-)-epicatechin: Differences between human and rat Reviewed

M Natsume, N Osakabe, M Oyama, M Sasaki, S Baba, Y Nakamura, T Osawa, J Terao

FREE RADICAL BIOLOGY AND MEDICINE 34 ( 7 ) 840 - 849 2003.4

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

(-)-Epicatechin is one of the most potent antioxidants present in the human diet. Particularly high levels are found in black tea, apples, and chocolate. High intake of catechins has been associated with reduced risk of cardiovascular diseases. There have been several reports concerning the bioavailability of catechins, however, the chemical structure of (-)-epicatechin metabolites in blood, tissues, and urine remains unclear. In the present study, we purified and elucidated the chemical structure of (-)-epicatechin metabolites in human and rat urine after oral administration. Three metabolites were purified from human urine including (-)-epicatechin-3'-O-glucuronide, 4'-O-methyl-(-)-epicatechin-3'-O-glucuronide, and 4'-O-methyl-(-)-epicatechin-5 or 7-O-glucuronide, according to H-1- and C-13-NMR, HMBC, and LC-MS analyses. The metabolites purified from rat urine were 3'-O-methyl-(-)-epicatechin, (-)-epicatechin-7-O-glucuronide, and 3'-O-methyl-(-)-epicatechin-7-O-glucuronide. These compounds were also detected in the blood of humans and rats by LC-MS. The presence of these metabolites in blood and urine suggests that catechins are metabolized and circulated in the body after administration of catechin-containing foods. (C) 2003 Elsevier Science Inc.

DOI： 10.1016/S0891-5849(02)01434-X

A phase II detoxification enzyme inducer from lemongrass: identification of citral and involvement of electrophilic reaction in the enzyme induction Reviewed

Y Nakamura, M Miyamoto, A Murakami, H Ohigashi, T Osawa, K Uchida

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 302 ( 3 ) 593 - 600 2003.3

Authorship：Lead author,　Last author Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

We have developed a simple system for the sensitive detection and measurement of glutathione S-transferase (GST) activity that detoxifies polycyclic aromatic hydrocarbons using the cultured rat normal liver epithelial cell line, RL34 cells. Citral (3,7-dimethyl-2,6-octadienal) was isolated from the methanol extract of lemongrass (Cymbopogon citratus) and identified as a novel inducer of GST. Citral, a mixture of the two stereoisomers geranial and neral, dose- and time-dependently induced the total and pi-class-specific activities of GST. The structure-activity relationship study revealed that geranial, an E-isomer, was mainly responsible for the inducing activity of citral mixture and the aldehyde group conjugated with a trans-double bond is an essential structural factor. The data were consistent with the in vitro observation that both glutathione (GSH) and protein thiol quickly and specifically reacted with the active isomer geranial, but not neral. Pretreatment of the cells with diethyl maleate significantly enhanced not only the basal activity but also the citral-stimulated activity of GST, while pretreatment with N-acetyl-cysteine inhibited it. Moreover, the treatment of RL 34 cells with geranial for 30 min significantly attenuated the intracellular GSH level, while application for 18 h enhanced it. These results strongly suggested that the electrophilic property characterized by the reactivity with intracellular nucleophiles including protein thiol or glutathione (GSH) plays an important role in the induction of GST. The present study also implied the antioxidant role of GST induction by citral in mouse skin, providing a new insight into skin cancer prevention. (C) 2003 Elsevier Science (USA). All rights reserved.

DOI： 10.1016/S0006-291X(03)00219-5

Induction of cytochrome P4501Al by autoclavable culture medium change in HepG2 cells Reviewed

Q Feng, T Kumagai, Y Nakamura, K Uchida, T Osawa

XENOBIOTICA 32 ( 11 ) 1033 - 1043 2002.11

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

1. Without the addition of xenobiotics, only by changing the Culture medium can one induce extensively and transiently cytochrome P4501A1 (CYP1A1) protein and mRNA in human hepatoma HepG2 cells. The induction was aryl hydrocarbon receptor (AhR)dependent, and was proven by: (1) the medium change activated the AhR, as judged by a electrophoretic mobility shift assay; and (2) the AhR inhibitor alpha-naphthoflavone inhibited the medium change-mediated induction.
2. Induction of CYP1A1 was related to medium prepared by autoclaving. By screening the ingredients in the medium, the serum had no effect on CYP1A1 induction, whereas both photo-oxidized and autoclaved tryptophan were shown to induce CYP1A1, as indicated by CYP1A1 protein or ethoxyresorufin-O-deethylase activity. The autoclaved tryptophan contained in an autoclavable medium was a more potent inducer of CYP1A1 than photo-oxidized tryptophan.
3. The results provide some practical suggestions with experiments related to CYP1A1.

DOI： 10.1080/0049825021000012583

Isolation and identification of DPPH radical scavenging compounds in Kurosu (Japanese unpolished rice vinegar) Reviewed

Y Shimoji, Y Tamura, Y Nakamura, K Nanda, S Nishidai, Y Nishikawa, N Ishihara, K Uenakai, H Ohigashi

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 50 ( 22 ) 6501 - 6503 2002.10

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Dihydroferulic acid (DFA) and dihydrosinapic acid (DSA) were isolated from Kurosu (unpolished rice vinegar) as the major constituents responsible for Kurosu's radical scavenging activity. The levels of antioxidative activity of DFA and DSA in DPPH radical scavenging were higher than those of their respective structurally related compounds, ferulic acid and sinapic acid. The concentrations of DFA and DSA were low in common rice vinegar (polished rice vinegar), suggesting that Kurosu is more advantageous than rice vinegars as an antioxidative food item. As the concentrations of DFA and DSA were low in unpolished rice, too, these acids are thought to be produced in Kurosu through the process of the fermentation from ferulic acid and sinapic acid, respectively.

DOI： 10.1021/jf020458f

FA15, a hydrophobic derivative of ferulic acid, suppresses inflammatory responses and skin tumor promotion: comparison with ferulic acid Reviewed

A Murakami, Y Nakamura, K Koshimizu, D Takahashi, K Matsumoto, K Hagihara, H Taniguchi, E Nomura, A Hosoda, T Tsuno, Y Maruta, HW Kim, K Kawabata, H Ohigashi

CANCER LETTERS 180 ( 2 ) 121 - 129 2002.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI IRELAND LTD

In our previous study. FA15 (2-methyl-I-butyl ferulic acid) was chemically synthesized as a novel ferulic acid (FA) analog, and found to notably suppress phorbol ester-induced Epstein-Barr virus activation and superoxide anion generation in vitro. In this report, we demonstrated that FA15 in contrast to FA, markedly Suppressed the combined lipopolysaccharide and interferon-gamma-induced protein expressions of inducible nitric oxide synthase and cyclooxygenase-2, and also inhibited the release of tumor necrosis factor-alpha accompanied by suppression of I-kappaB degradation in RAW264.7, a murine macrophage cell line. In ICR mouse skin, topical application of FA15 significantly attenuated phorbol ester-triggered hydrogen peroxide production and edema formation as well as papilloma development while that of FA did not. Our results suggest that FA15, derived front natural sources. is a novel chemopreventive agent, both structurally and functionally. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

DOI： 10.1016/S0304-3835(01)00858-8

Zerumbone, a Southeast Asian ginger sesquiterpene, markedly suppresses free radical generation, proinflammatory protein production, and cancer cell proliferation accompanied by apoptosis: the alpha,beta-unsaturated carbonyl group is a prerequisite Reviewed

A Murakami, D Takahashi, T Kinoshita, K Koshimizu, HW Kim, A Yoshihiro, Y Nakamura, S Jiwajinda, J Terao, H Ohigashi

CARCINOGENESIS 23 ( 5 ) 795 - 802 2002.5

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Zerumbone (ZER), a sesquiterpene from the edible plant Zingiber zerumbet Smith, has recently been found to suppress tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced Epstein-Barr virus activation in a potent manner. In the present study, we evaluated the antiinflammatory and chemopreventive potentials of ZER in a variety of cell culture experiments. ZER effectively suppressed TPA-induced superoxide anion generation from both NADPH oxidase in dimethylsulfoxide-differentiated HL-60 human acute promyelocytic leukemia cells and xanthine oxidase in AS52 Chinese hamster ovary cells. The combined lipopolysaccharide- and interferon-gamma-stimulated protein expressions of inducible nitric oxide synthase and cyclooxygenase (COX)-2, together with the release of tumor necrosis factor-alpha, in RAW 264.7 mouse macrophages were also markedly diminished. These suppressive events were accompanied with a combined decrease in the medium concentrations of nitrite and prostaglandin E-2, while the expression level of COX-1 was unchanged. ZER inhibited the proliferation of human colonic adenocarcinoma cell lines (LS174T, LS180, COLO205, and COLO320DM) in a dose-dependent manner, while the growth of normal human dermal (2F0-C25) and colon (CCD-18 Co) fibroblasts was less affected. It also induced apoptosis in COLO205 cells, as detected by dysfunction of the mitochondria transmembrane, Annexin V-detected translocation of phosphatidylserine, and chromatin condensation. Intriguingly, alpha-humulene, a structural analog lacking only the carbonyl group in ZER, was virtually inactive in all experiments conducted, indicating that the alpha,beta-unsaturated carbonyl group in ZER may play some pivotal roles in interactions with unidentified target molecule(s). Taken together, our results indicate that ZER is a food phytochemical that has distinct potentials for use in anti-inflammation, chemoprevention, and chemotherapy strategies.

Screening of edible Japanese plants for suppressive effects on phorbol ester-induced superoxide generation in differentiated HL-60 cells and AS52 cells Reviewed

HW Kim, A Murakami, Y Nakamura, H Ohigashi

CANCER LETTERS 176 ( 1 ) 7 - 16 2002.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI IRELAND LTD

Epithelial xanthine oxidase (XOD) is one of the major enzymes responsible for superoxide (O-2(-)) generation, which is involved in oxidative stress. However, there are few known reports of a convenient bioassay to detect Cellular XOD activity. We tested several cell lines, and found that AS52, from Chinese hamster ovary cells, produced a significant level of O-2(-) in 2 response to 12-O-tetradecanoylphorbol 13-acetate (TPA), and this activity was markedly inhibited by allopurinol, an XOD inhibitor. Using AS52 cells and differentiated HL-60 cells, we conducted screening tests of edible Japanese plant extracts for their inhibitory activities toward TPA-induced O-2(-) generation from both reduced nicotinamide adenine dinucleotide oxidase (HL-60) and XOD (AS52). Notably, the extracts from mioga ginger, rape, avocado, carrot, turnip, taro, and shiineji showed potent inhibition of O-2(-) generation in both cell lines. These results suggest that several edible Japanese plants carry a significant antioxidative and cancer preventive potential. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

DOI： 10.1016/S0304-3835(01)00735-2

A sulforaphane analogue that potently activates the Nrf2-dependent detoxification pathway Reviewed

Y Morimitsu, Y Nakagawa, K Hayashi, H Fujii, T Kumagai, Y Nakamura, T Osawa, F Horio, K Itoh, K Iida, M Yamamoto, K Uchida

JOURNAL OF BIOLOGICAL CHEMISTRY 277 ( 5 ) 3456 - 3463 2002.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Exposure of cells to a wide variety of chemoprotective compounds confers resistance to a broad set of carcinogens. For a subset of the chemoprotective compounds, protection is generated by an increase in the abundance of the protective phase II detoxification enzymes, such as glutathione S-transferase (GST). We have recently developed a cell culture system, using rat liver epithelial RL 34 cells, that potently responds to the phenolic antioxidants resulting in the induction of GST activity (Kawamoto, Y., Nakamura, Y., Naito, Y., Torii, Y., Kumagai, T., Osawa, T., Ohigashi, H., Satoh, K., Imagawa, M., and Uchida, K. (2000) J. Biol. Chem. 275, 11291-11299.) In the present study, we investigated the phase II-inducing potency of an isothiocyanate compound in vitro and in vivo and examined a possible induction mechanism. Based on an extensive screening of vegetable extracts for GST inducer activity in RL34 cells, we found Japanese horseradish, wasabi (Wasabia japonica, syn. Eutrema wasabi), as the richest source and identified 6-methylsulfinylhexyl isothiocyanate (6-HITC), an analogue of sulforaphane (4-methylsulfinylbutyl isothiocyanate) isolated from broccoli, as the major GST inducer in wasabi. 6-HITC potently induced both class alpha GSTA1 and class pi GSTP1 isozymes in RL34 cells. In animal experiments, we found that 6-MSHI was rapidly absorbed into the body and induced hepatic phase 11 detoxification enzymes more potently than sulforaphane. The observations that W 6-HITC activated the antioxidant response element (ARE), (ii) 6-HITC induced nuclear localization of the transcription factor Nrf2 that binds to ARE, and (iii) the induction of phase 11 enzyme genes by 6-HITC was completely abrogated in the nrf2-deficient mice, suggest that 6-HITC is a potential activator of the Nrf2/ARE-dependent detoxification pathway.

DOI： 10.1074/jbc.M110244200

Labdane-type Diterpene Dialdehyde, Pungent Principle of Myoga, Zingiber mioga Roscoe Reviewed

Masako Abe, Yoshio Ozawa, Yasushi Uda, Yoichi Yamada, Yasujiro Morimitsu, Yoshimasa Nakamura, Toshihiko Osawa

Bioscience, Biotechnology and Biochemistry 66 ( 12 ) 2698 - 2700 2002.1

Language：English Publishing type：Research paper (scientific journal)

The pungent principle of myoga (Zingiber mioga Roscoe) was identified as (E)-8β(17)-epoxylabd-12-ene-15,16-dial (miogadial) on the basis of its physical and spectroscopic properties (MS, NMR, IR, and UV). Galanal A and B, isolated as well as miogadial, had no hot taste. Reduced miogadial also was tasteless. The pungency of miogadial depended on the presence of αβ-unsaturated-1,4-dialdehyde group. © 2002 by Japan Society for Bioscience, Biotechnology, and Agrochemistry.

DOI： 10.1271/bbb.66.2698

Black tea polyphenols, theaflavins, prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P450 1A1 in cell cultures Reviewed

Q Feng, Y Torii, K Uchida, Y Nakamura, Y Hara, T Osawa

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 50 ( 1 ) 213 - 220 2002.1

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Tea polyphenols have been demonstrated as chemopreventive agents in a number of experimental models. However, less is known about the mechanism of chemoprevention by black tea compared with that of green tea. Some beneficial properties of theaflavins, the black tea polyphenols, were investigated in the present study. Theaflavins showed inhibitory effects on H2O2- and tert-butyl hydroperoxide (tBuOOH)-induced cytotoxicity (evaluated by tetrazolium bromide reduction), cellular oxidative stress (detected by oxidation of 2', 7'-dichlorofluorescin), and DNA damage (measured by amount of 8-OHdG and comet assay) in rat normal liver epithelium cell RL-34 cell lines. In addition, theaflavins also exhibited suppression of cytochrome P450 1A1 induced by omeprazole in the human hepatoma HepG2 cell line. Furthermore, when HepG2 cells were pretreated with omeprazole to induce CYP1A1, then exposed to benzo[a]pyrene (B[a]P), DNA damage was observed using the comet assay. However, theaflavins could inhibit this DNA damage. These results indicated that theaflavins could prevent cellular DNA damage by inhibiting oxidative stress and suppressing cytochrome P450 1A1 in cell cultures.

DOI： 10.1021/jf010875c

Role of p38 mitogen-activated protein kinase in the 4-hydroxy-2-nonenal-induced cyclooxygenase-2 expression Reviewed

T Kumagai, Y Nakamura, T Osawa, K Uchida

ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 397 ( 2 ) 240 - 245 2002.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

COX-2 is rapidly expressed by various stimuli and plays a key role in conversion of free arachidonic acid to prostaglandins (PGs). 4-Hydroxy-2-nonenal (HNE), one of the lipid peroxidation end-products, has been recently identified as a potent COX-2 inducer in rat epithelial cell RL34 cells (Kumagai et al (2000) Biochem. Biophys. Res. Commun. 273, 437-441. Here we investigated the molecular mechanism underlying the COX-2 induction by HNE mainly focusing on the activation of p38 mitogen-activated protein kinase (MAPK) pathways. The observations that (i) HNE induced phosphorylation of p38 MAPK and MKK3/MKK6 within 5 min and that (ii) SB203580, a p38 MAPK-specific inhibitor, suppressed the HNE-induced COX-2 expression suggested that the p38 MAPK pathway was involved in the HNE-induced COX-2 expression. Overexpression of p38 MAPK enhanced the HNE-induced COX-2 expression, whereas the overexpression of dominant negative p38 MAPK suppressed it. Furthermore, we also found that HNE upregulated the COX-2 expression by the stabilization of COX-2 mRNA via the p38 MAPK pathway. (C) 2001 Elsevier Science.

DOI： 10.1006/abbi.2001.2601

The amide hydrogen of (-)-indolactam-V and benzolactam-V8's plays a critical role in protein kinase C binding and tumor-promoting activities Reviewed

Y Nakagawa, K Irie, Y Nakamura, H Ohigashi

BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 11 ( 5 ) 723 - 728 2001.3

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

To investigate the role of the amide hydrogen of (-)-indolactam-V (1) and benzolactam-V8's on protein kinase C (PKC) binding and tumor promotion, 8-decylbenzolactone-V8 (6), a new lactone analogue of 8-decylbenzolactam-V8 (4), was synthesized from 2-nitrophenylpyruvic acid (7) in 11 steps. The PKC binding ability and tumor-promoting activities in vitro of 6 were much lower than those of 1 and 4, suggesting that the amide hydrogen of 1 and benzolactam-V8's plays a critical role in tumor promotion. However, it is noteworthy that 6 showed significant selectivity in the PKC isozyme surrogate binding. (C) 2001 Published by Elsevier Science Ltd.

DOI： 10.1016/S0960-894X(01)00047-6

The C4 hydroxyl group of phorbol esters is not necessary for protein kinase C binding Reviewed

M Tanaka, K Irie, Y Nakagawa, Y Nakamura, H Ohigashi, PA Wender

BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 11 ( 5 ) 719 - 722 2001.3

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

To investigate the role of the hydroxyl group at position 4 of the phorbol esters in protein kinase C (PKC) binding and function, 4 beta -deoxy-phorbol-12,13-dibutyrate (4 beta -deoxy-PDBu, 5a) and 4 beta -deoxy-phorbol-13-acetate (6a) were synthesized from phorbol (1). The binding affinities of these 4 beta -deoxy compounds (5a, 6a) to the 13 PKC isozyme C1 domains were quite similar to those of the corresponding 4 beta -hydroxy compounds (4a, 4b), suggesting that the C4 hydroxyl group of phorbol esters is not necessary for PKC binding. Moreover, functional assays showed that 4 beta -deoxy-PDBu (5a) exhibited biological activities (Epstein-Barr virus induction and superoxide generation) equally potent to those of PDBu (4a). These solution phase results differ from expectations based on the previously reported solid-phase structure of the complex of PKC delta -C1B and phorbol-13-acetate (4b). (C) 2001 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0960-894X(01)00045-2

Anticarcinogenic antioxidants as inhibitors against intracellular oxidative stress Reviewed

Q Feng, T Kumagai, Y Torii, Y Nakamura, T Osawa, K Uchida

FREE RADICAL RESEARCH 35 ( 6 ) 779 - 788 2001

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

Oxidative stress has been implicated in the pathogenesis of numerous diseases, including cancer. In the present study, the protective effect of natural antioxidants, such as quercetin and tea polyphenols, on intracellular oxidative stress was studied. Here we report a novel function of quercetin and tea polyphenols, as potential inhibitors of 4-hydroxy2-nonenal (HNE)-induced intracellular oxidative stress and cytotoxicity In rat liver epithelial RL34 cells, a potent electrophile HNE dramatically induced the productions of reactive oxygen species (ROS), which correlated well with the reduction in cell viability We found that quercetin and tea polyphenols, such as epigallocatechin gallate and theaflavins and their gallate esters, significantly inhibited the HNE-induced ROS production and cytotoxicity. In addition, HNE induced a transient decrease in the mitochondrial membrane potential (Deltapsi), which was also retarded by the antioxidants. These data suggest that the antioxidants, such as quercetin and tea polyphenols, are inhibitors against mitochondrial ROS production.

DOI： 10.1080/10715760100301281

Toxic dose of a simple phenolic antioxidant, protocatechuic acid, attenuates the glutathione level in ICR mouse liver and kidney Reviewed

Y. Nakamura, K. Torikai, H. Ohigashi

Journal of Agricultural and Food Chemistry 49 ( 11 ) 5674 - 5678 2001

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

It has previously been reported that a toxic dose of protocatechuic acid (PA), a naturally occurring simple phenolic antioxidant in dietary plant foodstuff, has a potential to enhance tumorigenesis and induce contact hypersensitivity in mouse skin. In this study, the modifying effect of a toxic dose of PA on the glutathione (GSH) level in mouse liver and kidney was examined. Intraperitoneal administration of PA (500 mg/kg) caused significant hepatic and nephrotic GSH depletion. Interestingly, slight but significant hepatotoxicity and nephrotoxicity, characterized by the enhancement of plasmic alanine aminotrasferase (ALT) activity and urea level, respectively, were also observed. The subchronic administration of PA (0.1% in drinking water) for 60 days showed not only a significant decrease in the GSH level in kidney but also a significant enhancement of ALT activity in plasma. The protective role of GSH for acute hepatotoxicity using GSH-depleted mice administered a GSH synthesis inhibitor buthionine sulfoximine was also demonstrated. Thus, it is suggested that overdoses of PA can disturb the detoxification of other electrophilic toxicants including ultimate carcinogens.

DOI： 10.1021/jf0106594

Suppression by citrus auraptene of phorbol ester and endotoxin-induced inflammatory responses: role of attenuation of leukocyte activation Reviewed

A Murakami, Y Nakamura, T Tanaka, K Kawabata, D Takahashi, K Koshimizu, H Ohigashi

CARCINOGENESIS 21 ( 10 ) 1843 - 1850 2000.10

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Auraptene (AUR), a citrus coumarin derivative, is one of the promising chemopreventive agents against skin, tongue, esophagus and colon carcinogenesis in rodents, We reported previously that AUR suppresses superoxide anion (O-2(-)) generation from inflammatory leukocytes in in vitro experiments, In the present study, we investigated the antiinflammatory activities of AUR using a 12-O-tetradecanoylphorbol-13-acetate-treated mouse skin model, and compared them with those nf umbelliferone (UMB), a structural analog of AUR that is virtually inactive toward O-2(-) generation inhibition. Double pre-treatments of mouse skin with AUR, but not UMB, markedly suppressed edema formation, hydrogen peroxide production, leukocyte infiltration, and the rate of proliferating cell nuclear antigen-stained cells. These inhibitory effects by AUR are attributable to its selective blockade of the activation stage, as revealed by single pre-treatment experiments. In a murine macrophage line, RAW 264.7, AUR significantly attenuated the lipopolysaccharide-induced protein expression of inducible isoforms of both nitric oxide synthase and cyclooxygenase, with decreased production of nitrite anion and prostaglandin E-2, and yet suppressed the release of tumor necrosis factor-alpha. Conversely, UMB did not show any inhibitory effect, This contrasting activity profile between AUR and UMB was rationalized to be a result of their distinct differences in cellular uptake efficiencies, i.e. the geranyloxyl group in AUR was found to play an essential role in incorporation Thus, our findings indicate that AUR is an effective agent to attenuate the biochemical responsiveness of inflammatory leukocytes, which may be essential for a greater understanding of the action mechanism that underlies its inhibition of inflammation-associated carcinogenesis.

DOI： 10.1093/carcin/21.10.1843

Inhibitory effect of citrus nobiletin on phorbol ester-induced skin inflammation, oxidative stress, and tumor promotion in mice Reviewed

A Murakami, Y Nakamura, K Torikai, T Tanaka, T Koshiba, K Koshimizu, S Kuwahara, Y Takahashi, K Ogawa, M Yano, H Tokuda, H Nishino, Y Mimaki, Y Sashida, S Kitanaka, H Ohigashi

CANCER RESEARCH 60 ( 18 ) 5059 - 5066 2000.9

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER ASSOC CANCER RESEARCH

The intake of citrus fruits has been suggested as a way to prevent the development of some types of human cancer. Nitric oxide (NO) is closely associated with the processes of epithelial carcinogenesis. We attempted a search for NO generation inhibitors in Cia rcs unshiu. The active constituent was traced by an activity-guiding separation. NO and superoxide (O(2)(-)) generation was induced by a combination of lipopolysaccharide and IFN-gamma in mouse macrophage RAW 264.7 cells, and by 12-O-tetradecanoylphorbol-13-acetate (TPA) in differentiated human promyelocyte HL-60, respectively. Expression of inducible NO synthase and cyclooxygenase 2 proteins were detected by Western blotting, The in vivo anti-inflammatory and antitumor promoting activities were evaluated by topical TPA application to ICR mouse skin with measurement of edema formation, epidermal thickness, leukocyte infiltration, hydrogen peroxide production, and the rate of proliferating cell nuclear antigen-stained cells. As a result, nobiletin, a polymethoxyflavonoid, was identified as an inhibitor of both NO and O(2)(-) generation, Nobiletin significantly inhibited two distinct stages of skin inflammation induced by double TPA application [first stage priming (leukocyte infiltration) and second stage activation (oxidative insult by leukocytes)] by decreasing the inflammatory parameters. It also suppressed the expression of cyclooxygenase-2 and inducible NO synthase proteins and prostaglandin E(2) release. Nobiletin inhibited dimethylbenz[a]anthracene (0.19 mu mol)/TPA (1.6 nmol)-induced skin tumor formation at doses of 160 and 320 nmol by reducing the number of tumors per mouse by 61.2% (P < 0.001) and 75.7% (P < 0.001), respectively. The present study suggests that nobiletin is a functionally novel and possible chemopreventive agent in inflammation-associated tumorigenesis.

4-hydroxy-2-nonenal, the end product of lipid peroxidation, is a specific inducer of cyclooxygenase-2 gene expression Reviewed

T Kumagai, Y Kawamoto, Y Nakamura, Hatayama, I, K Satoh, T Osawa, K Uchida

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 273 ( 2 ) 437 - 441 2000.7

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC

Cyclooxygenase-2 (COX-2), an enzyme responsible for catalyzing the committed step in prostanoid biosynthesis, is the product of an immediate early gene capable of being upregulated by diverse stimuli. Based on the experimental evidence that oxidative stress is associated with the upregulation of COX-2, we evaluated the effect of the oxidized fatty acid metabolites on COX-2 induction in rat liver epithelial RL34 cells, Among the compounds tested, only 4-hydroxy-2-nonenal (HNE), a highly mutagenic and genotoxic aldehyde generated during oxidative stress, dramatically induced COX-2. Enhanced gene expression of COX-2 by treatment with HNE was evident as a drastic elevation of the mRNA level. We also found that intracellular glutathione status was strictly related to HNE-induced COX-2 expression. These findings suggest the presence of a signaling pathway in the cellular response mediated by locally produced lipid peroxidation products under oxidative stress. (C) 2000 Academic Press.

DOI： 10.1006/bbrc.2000.2967

Novel nitric oxide and superoxide generation inhibitors, persenone A and B, from avocado fruit Reviewed

OK Kim, A Murakami, Y Nakamura, N Takeda, H Yoshizumi, H Ohigashi

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 48 ( 5 ) 1557 - 1563 2000.5

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

One known, (2R)-(12Z,15Z)-2-hydroxy-4-oxoheneicosa-12,15-dien-1-yl acetate (1), and two novel compounds, persenone A (2) and B (3), have been isolated from avocado fruit (Persea americana P. Mill), as inhibitors of superoxide (O-2(-)) and nitric oxide (NO) generation in cell culture systems. They showed marked inhibitory activities toward NO generation induced by lipopolysaccharide in combination with interferon-gamma in mouse macrophage RAW 264.7 cells. Their inhibitory potencies of NO generation (1, IC50 = 3.6; 2, IC50 = 1.2; and 3, IC50 = 3.5 mu M) were comparable to or higher than that of a natural NO generation inhibitor, docosahexaenoic acid (DKA; IC50 = 4.3 mu M). Furthermore, compounds 1-3 and DHA markedly suppressed tumor promoter 12-O-tetradecanoylphorbol-13-acetate-induced O-2(-) generation in differentiated human promyelocytic HL-60 cells (1, EC50 = 33.7; 2, IC50 = 1.4; 3, IC50 = 1.8; and DHA, IC50 = 10.3 mu M). It is notable that they were found to be suppressors of both NO- and O-2(-)-generating biochemical pathways but not to be radical scavengers. The results indicate that these compounds are unique antioxidants, preferentially suppressing radical generation, and thus may be promising as effective chemopreventive agent candidates in inflammation-associated carcinogenesis.

DOI： 10.1021/jf990977r

Cyclopentenone prostaglandins as potential inducers of phase II detoxification enzymes - 15-deoxy-Delta(12,14)-prostaglandin J2-induced expression of glutathione S-transferases Reviewed

Y Kawamoto, Y Nakamura, Y Naito, Y Torii, T Kumagai, T Osawa, H Ohigashi, K Satoh, M Imagawa, K Uchida

JOURNAL OF BIOLOGICAL CHEMISTRY 275 ( 15 ) 11291 - 11299 2000.4

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Exposure of cells to a wide variety of chemoprotective compounds confers resistance to a broad set of carcinogens. For a subset of the chemoprotective compounds, protection is generated by an increase in the abundance of protective enzymes, such as glutathione S-transferases (GSTs), In the present study, we developed a cell culture system that potently responds to phenolic antioxidants and found that antitumor prostaglandins (PGs) are potential inducers of GSTs, We screened primary hepatocytes and multiple cell lines for inducing GST activity upon incubation with the phenolic antioxidant (tert-butylhydroquinone) and found that rat liver epithelial RL34 cells most potently responded. Based on an extensive screening of diverse chemical agents on the induction of GST activity in RL34 cells, the J2 series of PGs, 15-deoxy-Delta(12,14)-prostaglandin J2 (15-deoxy-Delta(12,14)- PGJ2) in particular, were found to be potential inducers of GST, Enhanced gene expression of Class rr GST isozyme (GSTP1) by 15-deoxy-Delta(12,14)-PGJ2 was evident as a drastic elevation of the mRNA level, Hence, we examined the molecular mechanism underlying the 15-deoxy-Delta(12,14)-PGJ2-induced GSTP1 gene expression, From functional analysis of various deletion mutant genes, we found that the 15-deoxy-Delta(12,14)-PGJ2 reponse element was localized in a region containing a GSTP1 enhancer I (GPEI) that consists of two imperfect phorbol 12-O-tetradecanoylphorbol-13-acetate response elements. When the GPEI was combined with the minimum GSTP1 promoter, the element indeed showed an enhancer activity in response to 15-deoxy-Delta(12,14)-PGJ2. Point mutations of either of the two imperfect 12-O-tetradecanoylphorbol-13-acetate response elements in GPEI completely abolished the enhancer activity. Gel mobility shift assays demonstrated that 15-deoxy-Delta(12,14)-PGJ2 specifically stimulated the binding of nuclear proteins including the transcription factor c-Jun, but not Nrf2, to GPEI, These results suggest that 15-deoxy-Delta(12,14)-PGJ2 induces the expression of the rat GSTP1 gene through binding of proteins, including c-Jun, to a specific GPEI.

DOI： 10.1074/jbc.275.15.11291

Search for Naturally-occurring Antioxidative Chemopreventors on the Basis of the Involvement of Leukocyte-derived Reactive Oxygen Species in Carcinogenesis Reviewed

Yoshimasa Nakamura, Akira Murakami, Hajime Ohigashi

Asian Pacific Journal of Cancer Prevention 1 115 - 120 2000.1

Authorship：Lead author

Chemoprevention with food phytochemicals is currently regarded as one of the most attractive strategies for cancer control. We have been continuously working on the identification and characterization of chemopreventive phytochemicals extracted from a diverse range of edible plants. Recently, we have utilized a convenient assay, the tumor promoter-induced superoxide generation test, with differentiated HL-60 cells for primary screening, and performed chemical studies of antioxidative food phytochemicals. Here, we report our criteria for evaluation of new types of chemopreventors on the basis of the involvement of leukocyte-derived reactive oxygen in carcinogenesis.

Suppressive effects of citrus fruits on free radical generation and nobiletin, an anti-inflammatory polymethoxyflavonoid Reviewed

A Murakami, Y Nakamura, Y Ohto, M Yano, T Koshiba, K Koshimizu, H Tokuda, H Nishino, H Ohigashi

BIOFACTORS 12 ( 1-4 ) 187 - 192 2000

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

Citrus fruit intake is known to be associated with a reduction of cancer incidence. Free radicals, including superoxide (O(2)(-)) and nitric oxide (NO), are involved in some epithelial carcinogenesis processes. In the present study, we screened thirty-one citrus fruits for their suppressive activities toward three lines of free radical generating systems: 1) O(2)(-) generation by the xanthine (XA)-xanthine oxidase (XOD) system; 2) O(2)(-) generation induced by 1 2-O-tetradecanoylphorbol-13-acetate (TPA) in differentiated human promyelocytic HL-60 cells; and 3) NO generation in murine macrophage RAW264.7 cells stimulated with lipopolysaccharide (LPS) and interferon (IFN)-gamma. As a result, the inhibitory activities of peel parts were largely found to be higher than those of the corresponding juice sac parts. In particular, the peel portion of Dancy tangerine (Citrus tangerina) showed marked anti-oxidative activities in these systems. In addition, nobiletin, a polymethoxyflavonoid isolated from C. nobilis, showed a higher anti-inflammatory activity than indomethacin in a TPA-induced edema formation test in mouse ears. These results indicate that citrus fruits could be notable sources of anti-oxidative, anti-inflammatory, and cancer preventive compounds.

Kurosu, a traditional vinegar produced from unpolished rice, suppresses lipid peroxidation in vitro and in mouse skin Reviewed

Shoko Nishidai, Yoshimasa Nakamura, Koji Torikai, Mikako Yamamoto, Nobuhiro Ishihara, Hirotaka Mori, Hajime Ohigashi

Bioscience, Biotechnology and Biochemistry 64 ( 9 ) 1909 - 1914 2000

Language：English Publishing type：Research paper (scientific journal)

The in vitro antioxidative activities of various kinds of vinegar were investigated by using a linoleic acid autoxidation model detected by the thiobarbituric acid (TBA) method and the 1,1-diphenyl-2-picrylhydrazyl radical system. An ethyl acetate extract of Kurosu (EK), a vinegar made from unpolished rice, exhibited the highest antioxidative activity in both systems. EK (5 mg) inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced edema formation (14%) and myeloperoxidase activity (52%, P&lt
0.01) in female ICR mouse skin. Furthermore, EK significantly suppressed double TPA application-induced H2O2 generation (53%, P&lt
0.01) and lipid peroxidation determined by the TBA-reacting substance level (95%, P&lt
0.01). In a two-stage carcinogenesis experiment with dimethylbenz[a]anthracene/TPA, EK significantly reduced the number of tumors per mouse by 36% (P&lt
0.05) at 15 weeks after promotion. These results suggest that the antitumor-promoting effect may be partially due to the antioxidative properties of EK such as the decomposition of free radicals and interference with free radical-generating leukocytes. © 2000, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.64.1909

An avocado constituent, persenone A, suppresses expression of inducible forms of nitric oxide synthase and cyclooxygenase in macrophages, and hydrogen peroxide generation in mouse skin Reviewed

Oe Kyung Kim, Akira Murakami, Daisuke Takahashi, Yoshimasa Nakamura, Koji Torikai, Ha Won Kim, Hajime Ohigashi

Bioscience, Biotechnology and Biochemistry 64 ( 11 ) 2504 - 2507 2000

Language：English Publishing type：Research paper (scientific journal)

We investigated the suppressive effects of an avocado constituent, persenone A, on lipopolysaccharide- and interferon-γ-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) in a mouse macrophage cell line RAW 264.7. Persenone A at concentration of 20 μM almost completely suppressed both iNOS and COX-2 protein expression. In mouse skin, double treatments with persenone A (810 nmol) significantly suppressed double 12-O-tetradecanoylphorbol-13-acetate (TPA, 8.1 nmol) application-induced hydrogen peroxide (H2O2) generation. Treatment with persenone A before the second TPA treatment was sufficient to inhibit H2O2 generation, while the first treatment was not. This study thus suggests that persenone A is a possible agent to prevent inflammation-associated diseases including cancer. © 2000, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.64.2504

Inhibition by (-)-Persenone A-related compounds of nitric oxide and superoxide generation from inflammatory leukocytes Reviewed

Oe Kyung Kim, Akira Murakami, Yoshimasa Nakamura, Ha Won Kim, Hajime Ohigashi

Bioscience, Biotechnology and Biochemistry 64 ( 11 ) 2500 - 2503 2000

Language：English Publishing type：Research paper (scientific journal)

We have previously reported that persenone A, isolated from avocado fruit, is an effective inhibitor of both nitric oxide (NO) and superoxide (O2−) generation in cell culture systems. In this study, we have prepared four persenone A-related compounds and examined their inhibition of NO and O2− generation from inflammatory leukocytes. Some structural importance in persenone A to attenuate free radical generation is discussed. © 2000, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.64.2500

Synthesis and tumor-promoting activities of 12-Epi-phorbol-12,13-dibutyrate Reviewed

Kazuhiro Irie, Akifumi Nakahara, Yasuyuki Ikawa, Minoru Tanaka, Yu Nakagavva, Yoshimasa Nakamura, Hajime Ohigashi, Paul A. Wender

Bioscience, Biotechnology and Biochemistry 64 ( 11 ) 2429 - 2436 2000

Language：English Publishing type：Research paper (scientific journal)

12-Epi-phorbol-12,13-dibutyrate (1), the C12-epimer of the most frequently used phorbol ester probe, phorbol-12,13-dibutyrate (PDBu), has been synthesized from phorbol in 9 steps in order to investigate the structural requirements for tumor-promoting activity. Compound 1 showed about 100-fold weaker in vitro biological activities related to in vivo tumor promotion, Epstein-Barr virus early antigen (EBV-EA)-inducing ability, superoxide (O2 −) generation-inducing ability, and binding to the protein kinase C (PKC) regulatory domain surrogate peptides. The results indicated that the β-stereochemistry at position 12 of the phorbol skeleton is important for optimal activity. Binding selectivity to each PKC C1 domain of 1 was almost equal to that of PDBu. © 2000, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.64.2429

Nitric oxide synthase is induced in tumor promoter-sensitive, but not tumor promoter-resistant, JB6 mouse epidermal cells cocultured with interferon-γ-stimulated RAW 264.7 Cells: The role of tumor necrosis factor-α Reviewed

A. Murakami, K. Kawabata, T. Koshiba, G. Gao, Y. Nakamura, K. Koshimizu, H. Ohigashi

Cancer Research 60 ( 22 ) 6326 - 6331 2000

Language：English Publishing type：Research paper (scientific journal)

Expression of inducible nitric oxide synthase (iNOS) has been reported to be involved in certain organs of potential tumorigenesis, including the stomach and colon. The mechanisms for iNOS expression in epithelial cells, however, are not fully understood. In the present study, we investigated the role of macrophages in epithelial iNOS expression by coculturing a stimulated murine macrophage-like cell line, RAW 264.7, with either tumor promoter-sensitive (P+) or promoter-resistant (P-) JB6 murine epidermal cells. After monoculture, treatment of RAW 264.7 cells with IFN-γ for 24 h generated a large amount of nitrite (NO2-), as reported previously, whereas no increase in NO2- concentration was observed in the IFN-γ-treated P+ or P- subclones. Interestingly, when IFN-γ-treated RAW 264.7 cells were cocultured with P+ but not P- cells, we observed a marked increase in NO2- concentration (30.8 ± 3.6 μM), which significantly exceeded (P &lt
0.01) the sum of the concentrations (20.0 ± 2.3 μM) added from each cell line monoculture. Western blotting analysis revealed that, after coculture, iNOS protein was up-regulated 55-fold more than the control in JB6 P+ but not in P- cells. IFN-γ-treated RAW 264.7 cells secreted proinflammatory cytokines, including tumor necrosis factor (TNF)-α and interleukin (IL)-1β. The addition of IFN-γ-treated RAW 264.7 cell-conditioned media to P+ subclones led to a significant enhancement of NO2- formation that was diminished by the TNF-α-specific but not IL-1β-specific antibody. When combined with IFN-γ, the recombinant TNF-α (1-100 ng/ml) enhanced NO2- formation in JB6 P+ cells, whereas IL-1β (1-100 ng/ml) did not. These results led us to conclude that IFN-γ-treated RAW 264.7 cells release TNF-α to induce iNOS expression in promoter-sensitive JB6 cells. Thus, we propose the hypothesis that macrophages stimulate neoplastic cells with TNF-α via a paracrine loop to induce epithelial iNOS protein expression.

A diacetylenic spiroketal enol ether epoxide, AL-1, from Artemisia lactiflora inhibits 12-O-tetradecanoylphorbol-13-acetate-induced tumor promotion possibly by suppression of oxidative stress Reviewed

Y Nakamura, N Kawamoto, Y Ohto, K Torikai, A Murakami, H Ohigashi

CANCER LETTERS 140 ( 1-2 ) 37 - 45 1999.6

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI IRELAND LTD

The inhibitory effects of the diacetylenic spiroketal enol ether epoxide AL-1 from Artemisia lactiflora on a variety of tumor promoter-induced biological responses such as oxidative stress as well as tumor promotion in ICR mouse skin were investigated. AL-1 inhibited TPA-induced intracellular peroxide formation in differentiated HL-60 cells, suggesting that this suppression might be attributable to the inhibition of O-2(-) generation. In a double TPA application system in mouse skin, double pretreatments of AL-1 (810 nmol) significantly suppressed double TPA application-induced H2O2 generation. Pretreatment of AL-1 only before the second TPA treatment was sufficient to inhibit, while only with first treatment was not. From these results we concluded that AL-1 is a specific inhibitor of the activation phase in H2O2 production induced by double TPA treatments. In addition, AL-1 strongly inhibited tumor promoter-induced Epstein-Barr virus (EBV) activation in Raji cells (IC50 = 0.5 mu M), which was comparable to or even stronger than that of curcumin, a well-known antioxidative chemopreventer from turmeric. In a two-stage carcinogenesis experiment with TPA (topical application at 1.6 nmol) and 7,12-dimethylbenz[a]anthracene (DMBA, at 0.19 mu mol) in ICR mouse skin, topical application of AL-1 (at 160 nmol) significantly reduced tumor incidence, the numbers of tumors per mouse, and edema formation by 58% (P < 0.01 in t-test), 20% (P < 0.005 in chi(2)-test) and 42% (P < 0.01), respectively. These results together indicate that an inhibitor of O-2(-) generation is an effective chemopreventer of mouse skin carcinogenesis by their antioxidative property. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

DOI： 10.1016/S0304-3835(99)00048-8

Activation of stress signaling pathways by the end product of lipid peroxidation - 4-hydroxy-2-nonenal is a potential inducer of intracellular peroxide production Reviewed

K Uchida, M Shiraishi, Y Naito, Y Torii, Y Nakamura, T Osawa

JOURNAL OF BIOLOGICAL CHEMISTRY 274 ( 4 ) 2234 - 2242 1999.1

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

In the present study, we studied the signal transduction mechanism that is involved in the expression of c-Jun protein evident after exposure of rat liver epithelial RL34 cells to the major end product of oxidized fatty acid metabolism, 4-hydroxy-2-nonenal (HNE). HNE treatment of the cells resulted in depletion of intracellular glutathione (GSH) and in the formation of protein-bound HNE in plasma membrane. In addition, HNE strongly induced intracellular peroxide production, suggesting that HNE exerted oxidative stress on the cells. Potent expression of c-Jun occurred within 30 min of HNE treatment, which was accompanied by a time-dependent increase in activator protein-1 (AP-1) DNA binding activity. We found that HNE caused an immediate increase in tyrosine phosphorylation in RL34 cells, In addition, HNE strongly induced phosphorylation of c-Jun N-terminal kinases (JNK) and p38 mitogen-activated protein kinases and also moderately induced phosphorylation of extracellular signal-regulated kinases. The phosphorylation of JNK was accompanied by a rapid and transient increase in JNK and p38 activities, whereas changes in the activity of extracellular signal-regulated kinase were scarcely observed. GSH depletion by L-buthionine-S,R-sulfoximine, a specific inhibitor of GSH biosynthesis, only slightly enhanced peroxide production and JNK activation, suggesting that HNE exerted these effects independent of GSH depletion. This and the findings that (i) HNE strongly induced intracellular peroxide production, (ii) HNE-induced JNK activation was inhibited by pretreatment of the cells with a thiol antioxidant, N-acetylcysteine, and (iii) H2O2 significantly activated JNK support the hypothesis that pro-oxidants play a crucial role in the HNE-induced activation of stress signaling pathways. In addition, we found that, among the inhibitors of tyrosine kinases, cyclooxygenase, and Ca2+ influx, only quercetin exerted a significant inhibitory effect on HNE-induced JNK activation. In light of the JNK-dependent induction of c-jun transcription and the AP-1-induced transcription of xenobiotic-metabolizing enzymes, these data may show a potential critical role for JNK in the induction of a cellular defense program against toxic products generated from lipid peroxidation.

DOI： 10.1074/jbc.274.4.2234

Isolation and identification of acetylenic spiroketal enol ethers from Artemisia lactiflora as inhibitors of superoxide generation induced by a tumor promoter in differentiated HL-60 cells Reviewed

Y Nakamura, Y Ohto, A Murakami, S Jiwajinda, H Ohigashi

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 46 ( 12 ) 5031 - 5036 1998.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Six acetylenic compounds were isolated from the leaves of Artemisia lactiflora (Compositae), an edible plant of Thailand. Four of them were identified as the stereoisomers of 3,4-epoxy-2-(2,4-hexadiynylidene)-1,6-dioxaspiro[4.5]decane and its derivatives, whose planar structures have already been reported. The other two were identified as novel chlorohydrin derivatives of the corresponding diacetylene spiroketal enol ethers. The inhibitory effects of the polyacetylenes isolated in the present study together with genistein on TPA-induced O-2(-) generation were examined. It was revealed that an acyloxyl group at the C-2 position enhanced-the inhibitory effect, while the absolute configurations at C-5, -6, and -7 were not important. While polyacetylenes are known to possess several biological roles in various ecosystems, we first found inhibitory effects of the diacetylenes on TPA-induced O-2(-) generation in differentiated HL-60 cells.

DOI： 10.1021/jf980521u

Superoxide scavenging activity of rosmarinic acid from Perilla frutescens Britton var. acuta f. viridis Reviewed

Y Nakamura, Y Ohto, A Murakami, H Ohigashi

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 46 ( 11 ) 4545 - 4550 1998.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Rosmarinic acid (RoA) has been isolated in high yield (0.1%) from the leaves of Perilla frutescens Britton var, acuta f. viridis, one of the most common garnishes in Japan, as a superoxide scavenger in a xanthine/xanthine oxidase system. The scavenging activity of RoA was significantly higher than that of ascorbic acid (AA). The structure-activity relationships using RoA, caffeic acid (CaA), and its related compounds indicated that the presence of an ortho dihydroxyphenyl group is essential for the scavenging effect. In addition, the conjugated double bond in the C3 carbon chain is important for enhancing the effect. The activity of RoA was then shown to be due to the additive effect of both CaA and (3,4-dihydroxyphenyl)lactic acid units, both of which are hydrolyzed products of RoA. RoA significantly inhibited both intracellular superoxide and peroxide formation in differentiated HL-60 cells, suggesting that RoA effectively exhibited antioxidative activity in the biological systems through the scavenging of superoxide.

DOI： 10.1021/jf980557m

Screening of edible Japanese plants for nitric oxide generation inhibitory activities in RAW 264.7 cells Reviewed

OK Kim, A Murakami, Y Nakamura, H Ohigashi

CANCER LETTERS 125 ( 1-2 ) 199 - 207 1998.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI IRELAND LTD

A total of 48 (60 test samples) species of plants commonly eaten in Japan were randomly collected and their methanol extracts were tested for in vitro nitric oxide (NO) generation inhibitory activities in a murine macrophage cell line, RAW 264.7, stimulated with both lipopolysaccharide (LPS, 100 ng/ml) and interferon-gamma (IFN-gamma, 100 U/ml). Seventeen (28.3%) of the 48 extracts strongly inhibited NO generation at a concentration of 200 mu g/ml by 70% or more with significant cell viability (>50%). The extracts from avocado, tare, red turnip, sereves, komatsuna, basil, mitsuba and Chinese mustard markedly inhibited iNOS activity. These results suggest that a wide variety of edible plants in Japan contain the secondary metabolites carrying cancer preventive activity through reduction of excess amounts of NO. (C) 1998 Elsevier Science Ireland Ltd.

DOI： 10.1016/S0304-3835(97)00513-2

Synthesis and Biological Activities of (-)-6-n-Octyl-indolactam-V, a New Potent Analogue of the Tumor Promoter (-)-Indolactam-V Reviewed

Yu Nakagawa, Kazuhiro Irie, Yoshimasa Nakamura, Hajime Ohigashi, Hideo Hayashi

Bioscience, Biotechnology and Biochemistry 62 ( 8 ) 1568 - 1573 1998

Language：English Publishing type：Research paper (scientific journal)

(-)-Indolactam-V (1) without a hydrophobic chain at positions 6 and 7 of the indole ring is a weak tumor promoter compared with teleocidin Bs. To investigate the effects of the hydrophobic substituent at position 6 of teleocidin Bs, we synthesized (-)-6-n-octyl-indolactam-V (2) by a palladium-catalyzed coupling reaction from (-)-6-bromo-indolactam-V (7) which had been obtained by microbial conversion with Streptoverticillium blastmyceticum NA34-17 as the key step. (-)-7-n-Octyl-indolactam-V (3) with potent biological activities comparable to those of teleocidin Bs was similarly synthesized from (-)-7-bromo-indolactam-V as a positive control. Compound 2 showed similar biological activities to those of 3, indicating that the effect of the hydrophobic substituent at position 6 of 1 was identical to that at position 7. © 1998, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.62.1568

Cellular response to the redox active lipid peroxidation products: Induction of glutathione S-transferase P by 4-hydroxy-2-nonenal Reviewed

A Fukuda, Y Nakamura, H Ohigashi, T Osawa, K Uchida

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 236 ( 2 ) 505 - 509 1997.7

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS

Membrane lipid peroxidation is known to produce various aldehydic compounds which cause a wide range of biological effects including heart disease, aging, and cancer. To investigate the effect of lipid peroxidation products on the expression of glutathione S-transferases (GSTs), which catalyze the conjugation of reactive chemicals with glutathione and play an important role in protecting cells, normal rat liver epitherial cells (RL34) were exposed to a variety of aldehydic compounds. We found that the GST activity in RL34 cells was induced by alpha,beta-unsaturated aldehydes, such as acrolein (1.3-fold), crotonaldehyde (1.3-fold), 4-hydroxy-2-hexenal (HHE) (1.4-fold), and 4-hydroxy-2-nonenal (HNE) (1.7-fold). The induction of GST activity by HNE was time-dependent, reaching a plateau after 16 h. The immunoblot analysis using the polyclonal antibodies against GST isozymes demonstrated that GST-P (pi-class), a well-known tumor marker, was significantly induced 16 h after the HNE treatment. Also, immunostaining for the presence of GST-P confirmed the enhanced expression of GST-P in the cytoplasm of the cells, Northern blot analysis revealed that the HNE treatment of RL34 cells for 1 h enhanced the expression of GST-P mRNA, which returned to the control level after 16 h. These data suggest that the induction of GST-P by HNE may represent an important cellular defense mechanism against oxidative injury. (C) 1997 Academic Press.

DOI： 10.1006/bbrc.1997.6585

Auraptene, a citrus coumarin, inhibits 12-O-tetradecanoylphorbol-13-acetate-induced tumor promotion in ICR mouse skin, possibly through suppression of superoxide generation in leukocytes Reviewed

A Murakami, W Kuki, Y Takahashi, H Yonei, Y Nakamura, Y Ohto, H Ohigashi, K Koshimizu

JAPANESE JOURNAL OF CANCER RESEARCH 88 ( 5 ) 443 - 452 1997.5

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPANESE CANCER ASSOC

Coumarin-related compounds, auraptene and umbelliferone, have been isolated from the cold-pressed oil of natsumkian (Citrus natsudaidai HAYATA), and tested as inhibitors of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced Epstein-Barr virus activation in Raji cells. The 50% inhibitory concentration (IC50) of auraptene (18 mu M) was almost equal to that of genistein. Umbelliferone, which lacks a geranyloxyl group present in auraptene, was less active (IC50 = 450 mu M). In a two-stage carcinogenesis experiment with 7,12-dimethylbenz[a]anthracene (topical application at 0.19 mu mol) and TPA (topical application at 1.6 nmol) in ICR mouse skin, topical application of auraptene (at 160 nmol) significantly reduced tumor incidence and the numbers of tumors per mouse by 27% (P < 0.01) and 23% (P < 0.05), respectively. Auraptene at a concentration of 50 mu M markedly suppressed superoxide (O-2(-)) generation induced by 100 nM TPA in differentiated human promyelocytic HL-60 cells. Having no O-2(-) scavenging potential, auraptene may inhibit the multicomponent NADPH oxidase system, Inhibition of intracellular hydroperoxide formation in differentiated HL-60 cells by auraptene was also confirmed by flow-cytometric analysis using 2',7'-dichlorofluorescein diacetate as a fluorescence probe. Quantitative analyses using high-performance liquid chromatography showed the occurrence of auraptene not only in both the peels and sarcocarps of natsumikan, but also in those of hassaku orange (C. hassaku) and grapefruit (C. paradisi), and even in their bottled fresh juice form. These results indicate that auraptene is a chemopreventer of skin tumorigenesis, and implies that suppression of leukocyte activation might be the mechanism through which it inhibits tumor promotion.

Synthesis and Biological Activities of Indolactone-V, the Lactone Analogue of the Tumor Promoter (–)-Indolactam-V Reviewed

Yu Nakagawa, Kazuhiro Irie, Yoshimasa Nakamura, Hajime Ohigashi, Hideo Hayashi

Bioscience, Biotechnology and Biochemistry 61 ( 8 ) 1415 - 1417 1997

Language：English Publishing type：Research paper (scientific journal)

The tumor promoter (–)-indolactam-V (1) exists in two stable conformers (twist and sofa) due to isomerization of the amide group. Indolactone-V (2), the lactone analogue of 1, has been synthesized to investigate the effects of the amide group on its conformation and biological activities. Indolactone-V (2) existed only as the inactive sofa-like conformer, indicating that the amide group of 1 plays a critical role in formation of the active twist conformation. © 1997, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.61.1415

Synthesis and biological activities of new conformationally restricted analogues of (-)-indolactam-V: Elucidation of the biologically active conformation of the tumor-promoting teleocidins Reviewed

K Irie, T Isaka, Y Iwata, Y Yanai, Y Nakamura, F Koizumi, H Ohigashi, PA Wender, Y Satomi, H Nishino

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 118 ( 44 ) 10733 - 10743 1996.11

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

The tumor-promoting teleocidins and their core structure (-)-indolactam-V (1) exist in two stable conformers in solution at room temperature. The cis amide assumes a twist conformation while the trans amide exists in a sofa form. In order to identify the biologically active conformation of the teleocidins, we have synthesized new twist-restricted analogues 5a and 6 based on an aza-Claisen rearrangement of (-)-N-13-desmethyl-N-13-allylindolactam-V (3) and a sofa-restricted analogue, (-)-5-methylindolactam-V (22). The activities of these new compounds were evaluated in three in vitro bioassays associated with in vivo tumor-promoting activity: binding to the protein kinase C regulatory domain, induction of the Epstein-Barr virus early antigen, and stimulation of radioactive inorganic phosphate incorporation into phospholipids of HeLa cells. These three biological activities correlated well for each derivative, Twist-restricted analogues 5a and 6 showed significant activities in the three assays, comparable to 1 itself. In contrast, sofa-restricted 22 showed little activity related to tumor promotion. Introduction of a prenyl group into position 7 or 18 of 5a and 6 significantly enhanced the activity while sofa-restricted (-)-5-prenylindolactam-V (23) showed only very weak activity. These results indicate that the active conformation of the teleocidins and 1 is close to the twist form. This is the first evidence beating on the active conformation of the teleocidins based on conformationally restricted analogues with an intact indolactam skeleton and is in accord with conclusions reported for benzolactams, analogues without the pyrrole moiety. This study also describes the synthesis of hew biologically active compounds (26a, 26b, 28) based on inactive (+)-epiindolactam-V (24), involving a further application of the aza-Claisen rearrangement. Bridge formation between positions 5 and 13 of indolactam derivatives represents a particularly effective analogue design strategy, allowing for the remote control of the conformation of this ring system and for the introduction of a wide range of structural variations, as required for the development of new protein kinase C activators with high isozyme selectivity.

DOI： 10.1021/ja961727j

1’prime;-Acetoxychavicol acetate, a superoxide anion generation inhibitor, potently inhibits tumor promotion by 12-O-tetradecanoylphorbol-13-acetate in ICR mouse skin Reviewed

Akira Murakami, Shin Ohura, Yoshimasa Nakamura, Koichi Koshimizu, Hajime Ohigashi

Oncology (Switzerland) 53 ( 5 ) 386 - 391 1996.1

Language：English Publishing type：Research paper (scientific journal)

The anti-tumor-promoting activity of 1’-acetoxychavicol acetate (ACA) was examined in a two-stage carcinogenesis experiment in ICR mouse skin using 7,12-dimethylbenz[a]anthracene (0.19 μmol) and 12-O-tetradecanoylphorbol-13-acetate (TPA
1.6 nmol). Topical application of ACA (160 nmol) markedly reduced the average number of tumors per mouse and the ratio of tumor-bearing mice: inhibition ratios 90% (p &lt
0.001) and 42% (p &lt
0.005), respectively. ACA even at a dose equimolar to TPA (1.6 nmol) significantly reduced theaverage number of tumors per mouse: inhibitory ratio 44% (p &lt
0.05). ACA potently inhibited TPA-induced superoxide (O2) generation in differentiated HL-60 cells (IC50 = 4.3μM) and suppressed the lipid hydroperoxide formation by42% (p &lt
0.001) in the ethyl linoleate autoxidation test. © 1996 S. Karger AG, Basel.

DOI： 10.1159/000227593

Photocytotoxicity of water-soluble fullerene derivatives Reviewed

Kazuhiro Irie, Yoshimasa Nakamura, Hajime Ohigashi, Hidetoshi Tokuyama, Shigeru Yamago, Eiichi Nakamura

Bioscience, Biotechnology and Biochemistry 60 ( 8 ) 1359 - 1361 1996

Language：English Publishing type：Research paper (scientific journal)

New water-soluble fullerene carboxylic acids (1 and 2) derived from C60 and C70 fullerenes, respectively, were examined for photocytotoxicity toward Raji cells (B lymphocyte). These compounds did not show any photocytotoxic effect even at 50μ m, while pheophorbide a showed significant photocytotoxicity at 0.5 μ m. Therefore, fullerene derivatives derived from C60 and C70 would not be practical agents for photodynamic therapy. © 1996, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.60.1359

Identification of Pheophorbide a and Its Related Compounds as Possible Anti-tumor Promoters in the Leaves of Neptunia oleracea Reviewed

Yoshimasa Nakamura, Akira Murakami, Koichi Koshimizu, Hajime Ohigashi

Bioscience, Biotechnology and Biochemistry 60 ( 6 ) 1028 - 1030 1996

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Six chlorophyll-related compounds isolated from leaves of Neptunia oleracea (Leguminosae) inhibited the activation of tumor promoter-induced Epstein-Barr virus (EBV). Photo-irradiation of pheophorbide a, the major active constituent, did not enhance this inhibitory activity, and thus ruled out any photosensitizing effect playing the major role. © 1996, Taylor &amp
Francis Group, LLC. All rights reserved.

DOI： 10.1271/bbb.60.1028

GLYCEROGLYCOLIPIDS FROM CITRUS HYSTRIX, A TRADITIONAL HERB IN THAILAND, POTENTLY INHIBIT THE TUMOR-PROMOTING ACTIVITY OF 12-O-TETRADECANOYLPHORBOL 13-ACETATE IN MOUSE SKIN Reviewed

A MURAKAMI, Y NAKAMURA, K KOSHIMIZU, H OHIGASHI

JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 43 ( 10 ) 2779 - 2783 1995.10

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Two glyceroglycolipids were isolated from the leaves of Citrus hystrix (bitter orange), a traditional herb in Thailand. They were identified as 1,2-di-O-alpha-linolenoyl-3-O-beta-galactopyransyl-sn-glycerol (DLGG, I) and a mixture of two compounds, 1-O-alpha-linolenoyl-2-O-palmitoyl-3-O-beta-galactopyranosyl-sn-glycerol (2a) and its counterpart (2b) (LPGG, 2). Both lipids were potent inhibitors of tumor promoter-induced Epstein-Barr virus (EBV) activation. The IC50 values of 1 and 2 were strikingly lower than those of representative cancer preventive agents such as alpha-linolenic acid, beta-carotene, or (-)-epigallocatechin gallate. In a two-stage carcinogenesis experiment on ICR mouse skin with dimethylbenz[alpha]anthracene (DMBA) and 12-O-tetradecanoylphorbol 13-acetate (TPA), compound 1 exhibited anti-tumor-promoting activity even at a dose 10 times lower than that of alpha-linolenic acid. As some synthetic detergents or saponins were entirely inactive in the EBV activation inhibition test, detergency was suggested not to play a major role in the mode of inhibitory action in vivo. The inhibition of the arachidonic acid cascade may be involved in anti-tumor promotion since 1 inhibited TPA-induced edema formation in the anti-inflammation test using ICR mouse ears.

DOI： 10.1021/jf00058a043

SYNTHESIS AND BIOLOGICAL-ACTIVITIES OF NEW CONFORMATIONALLY FIXED ANALOGS OF (-)-INDOLACTAM-V, THE CORE STRUCTURE OF TUMOR-PROMOTING TELEOCIDINS Reviewed

K IRIE, F KOIZUMI, Y IWATA, T ISHII, Y YANAI, Y NAKAMURA, H OHIGASHI, PA WENDER

BIOORGANIC & MEDICINAL CHEMISTRY LETTERS 5 ( 5 ) 453 - 458 1995.3

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

(-)-Indolactam-V(1) exists as two stable conformers, the twist and the sofa form, in solution at room temperature. 3-Aza-Cope rearrangement of (-)-N-13-desmethyl-N-13-allylindolactam-V (5) gave new conformationally restricted analogues (2a and 3) along with a normal rearrangement product (7). Both 2a and 3, whose fixed conformation was the twist form, showed significant biological activities related to tumor promotion.

DOI： 10.1016/0960-894X(95)00047-W

Possible anti-tumor promoting properties of edible plants from thailand, and identification of an active constituent, cardamonin, of boesenbergia pandurata Reviewed

Akira Murakami, Akira Kondo, Yoshimasa Nakamura, Hajime Ohigashi, Koichi Koshimizu

Bioscience, Biotechnology and Biochemistry 57 ( 11 ) 1971 - 1973 1993

Language：English Publishing type：Research paper (scientific journal)

Possible anti-tumor promoting properties of a total of 40 methanol extracts from Thai edible plants, including 5 non-edible species, were estimated in vitro by an inhibition test of tumor promoter-induced Epstein-Barr virus (EBV) activation. Fourteen species (35% of the total) were found to be strongly active. In addition, cardamonin (2′,4′-dihydroxy-6′-methoxychalcone) was identified as a potently active constituent (IC50 = 3.1μM) of Boesenbergia pandurata (Zingiberaceae), suggesting it to be an effective anti-tumor promoter. © 1993 Taylor &amp
Francis Group LLC.

DOI： 10.1080/bbb.57.1971

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