Updated on 2025/08/15

写真a

 
NAKAMURA Toshiyuki
 
Organization
Faculty of Environmental, Life, Natural Science and Technology Associate Professor
Position
Associate Professor
External link

Degree

  • 博士

Research Interests

  • Food function

Research Areas

  • Life Science / Food sciences

 

Papers

  • 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

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    DOI: 10.1093/bbb/zbaf062

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

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

    Journal of plant physiology   306   154447 - 154447   2025.2

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    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

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

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

    Physiologia plantarum   177 ( 1 )   e70094   2025

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    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

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  • 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

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    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

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  • Quercetin Attenuates Acetaldehyde-Induced Cytotoxicity via the Heme Oxygenase-1-Dependent Antioxidant Mechanism in Hepatocytes. 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

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    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

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  • 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 Reviewed

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

    Nutraceuticals   2024.8

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    DOI: 10.3390/nutraceuticals4030024

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  • 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

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    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

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  • 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

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    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

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  • 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

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    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

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  • 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   1 - 16   2024.2

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    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

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  • 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   2023.8

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    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

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  • 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

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    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

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

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    Authorship:Lead author   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

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  • The stability and reactivity of isothiocyanates and the plausible behavior of their dithiocarbamate- and thiourea-conjugates Reviewed

    Nakamura Toshiyuki

    Journal of Biological Macromolecules   23 ( 1 )   13 - 17   2023

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    Authorship:Lead author, Corresponding author   Language:English   Publisher:Japan Science Society of Biological Macromolecules  

    Isothiocyanates (ITCs) are organosulfur compounds derived from cruciferous plants. An electrophilic ITC group (-N=C=S) reacts with some functional groups such as a hydroxyl ion, a thiol group and amine groups in proteins. It is known that ITCs are decomposed easily by the addition of a hydroxyl ion to the ITC group in aqueous solutions. In the intracellular behavior, the primary target of ITCs is a thiol group, which results in the formation of their dithiocarbamate conjugates. The reaction is considered to induce the health promoting and disease preventive effects of ITCs. ITCs also react with amine groups to form stable thioureas. This review offers a short summary of the stability and reactivity of ITCs and the plausible behavior of their dithiocarbamate- and thiourea-conjugates.

    DOI: 10.14533/jbm.23.13

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  • 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

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    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

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  • 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

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    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

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  • 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

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    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

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  • 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

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    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

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  • 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

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    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

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  • 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

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    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

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  • 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 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

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    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.

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  • RING FISSION CATABOLITES OF QUERCETIN GLYCOSIDES

    LI Kexin, NAKAMURA Toshiyuki, NAKAMURA Yoshimasa

    Journal of Environmental Science for Sustainable Society (Web)   11 ( Supplement )   2022

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  • 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

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    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.

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  • 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

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    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.

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  • 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

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    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.

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  • 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

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    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.

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  • Predominant rice phytochemicals and their disease-preventive effects

    Hongyan WU, Toshiyuki NAKAMURA, Yoshimasa NAKAMURA

    Journal of Environmental Science for Sustainable Society   10 ( Supplement )   MR01_p1 - MR01_p4   2021.4

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    DOI: 10.3107/jesss.10.mr01

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  • Neither glutamate nor alanine but arginine sensitizes BY-2 cells to arsenate.

    Nahar, M.N., Prodhan, M.Y., Mimata, Y., Yonezawa, A., Nakamura, T., Nakamura, Y., Munemasa, S., Murata, Y.

    Biosci. Biotechnol. Biochem.   2021

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  • 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

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  • 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

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    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.

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  • 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

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    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.

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  • 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

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    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.

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  • 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

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    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.

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  • 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

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    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.

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  • 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

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    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.

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  • 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   2019.4

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    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.

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  • The golgin protein giantin regulates interconnections between Golgi stacks Reviewed

    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   2019

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  • 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

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    <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

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  • 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

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    <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

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  • 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

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  • 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

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  • 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 ( Pt A )   305 - 313   2017.10

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  • 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

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  • (-)-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

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  • Oleuropein aglycone enhances UCP1 expression in brown adipose tissue in high-fat-diet-induced obese rats by activating beta-adrenergic signaling Reviewed

    Yuriko Oi-Kano, Yusaku Iwasaki, Toshiyuki Nakamura, Tatsuo Watanabe, Tsuyoshi Goto, Teruo Kawada, Kenichi Watanabe, Kazuo Iwai

    JOURNAL OF NUTRITIONAL BIOCHEMISTRY   40   209 - 218   2017.2

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  • 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

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    DOI: 10.1080/09168451.2017.1374830

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  • 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

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    DOI: 10.1080/09168451.2017.1332979

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  • 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

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    DOI: 10.1080/09168451.2017.1340088

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  • 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

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    DOI: 10.1080/09168451.2017.1361809

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  • 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

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    DOI: 10.1016/j.bbrep.2016.06.020

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  • Activation of transient receptor potential ankyrin 1 by quercetin and its analogs Reviewed

    Toshiyuki Nakamura, Noriyuki Miyoshi, Takeshi Ishii, Miyu Nishikawa, Shinichi Ikushiro, Tatsuo Watanabe

    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY   80 ( 5 )   949 - 954   2016.5

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    DOI: 10.1080/09168451.2015.1132148

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  • 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

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    DOI: 10.3136/fstr.22.847

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  • Location of α-tocopherol and α-tocotrienol to heterogeneous cell membranes and inhibition of production of peroxidized cholesterol in mouse fibroblasts Reviewed

    Toshiyuki Nakamura, Ayako Noma, Junji Terao

    Journal of the Korean Physical Society   3 ( 1 )   1 - 6   2014.9

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    DOI: 10.1186/2193-1801-3-550

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  • Plasma metabolites of dietary flavonoids after combination meal consumption with onion and tofu in humans Reviewed

    Toshiyuki Nakamura, Kaeko Murota, Shun Kumamoto, Kazuhiro Misumi, Noriko Bando, Shinichi Ikushiro, Nobuyuki Takahashi, Keiko Sekido, Yoji Kato, Junji Terao

    MOLECULAR NUTRITION & FOOD RESEARCH   58 ( 2 )   310 - 317   2014.2

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    DOI: 10.1002/mnfr.201300234

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  • The human bitter taste receptor hTAS2R39 is the primary receptor for the bitterness of theaflavins Reviewed

    Toyomi Yamazaki, Miki Sagisaka, Riko Ikeda, Toshiyuki Nakamura, Noriko Matsuda, Takeshi Ishii, Tsutomu Nakayama, Tatsuo Watanabe

    Bioscience, Biotechnology and Biochemistry   78 ( 10 )   1753 - 1756   2014

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    DOI: 10.1080/09168451.2014.930326

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  • Immunomodulatory activity of enzymatically synthesized glycogen and its digested metabolite in a co-culture system consisting of differentiated Caco-2 cells and RAW264.7 macrophages Reviewed

    Michiko Yasuda, Takashi Furuyashiki, Toshiyuki Nakamura, Ryo Kakutani, Hiroki Takata, Hitoshi Ashida

    FOOD & FUNCTION   4 ( 9 )   1387 - 1393   2013.9

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    DOI: 10.1039/c3fo60035a

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  • Plasma HDL Reduces Nonesterified Fatty Acid Hydroperoxides Originating from Oxidized LDL: a Mechanism for Its Antioxidant Ability Reviewed

    Mari Kotosai, Sachiko Shimada, Mai Kanda, Namiko Matsuda, Keiko Sekido, Yoshibumi Shimizu, Akira Tokumura, Toshiyuki Nakamura, Kaeko Murota, Yoshichika Kawai, Junji Terao

    LIPIDS   48 ( 6 )   569 - 578   2013.6

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    DOI: 10.1007/s11745-013-3779-1

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  • Non-selective distribution of isomeric cholesterol hydroperoxides to microdomains in cell membranes and activation of matrix metalloproteinase activity in a model of dermal cells Reviewed

    Toshiyuki Nakamura, Ayako Noma, Sachiko Shimada, Nanase Ishii, Noriko Bando, Yoshichika Kawai, Junji Terao

    Chemistry and Physics of Lipids   174   17 - 23   2013

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    DOI: 10.1016/j.chemphyslip.2013.05.004

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  • Fermented Tea Improves Glucose Intolerance in Mice by Enhancing Translocation of Glucose Transporter 4 in Skeletal Muscle Reviewed

    Yoko Yamashita, Lihua Wang, Zhang Tinshun, Toshiyuki Nakamura, Hitoshi Ashida

    JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY   60 ( 45 )   11366 - 11371   2012.11

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    DOI: 10.1021/jf303597c

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  • Absorption and metabolism of 4-hydroxyderricin and xanthoangelol after oral administration of Angelica keiskei (Ashitaba) extract in mice Reviewed

    Toshiyuki Nakamura, Takahiro Tokushima, Kyuichi Kawabata, Norio Yamamoto, Masaaki Miyamoto, Hitoshi Ashida

    ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS   521 ( 1-2 )   71 - 76   2012.5

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    DOI: 10.1016/j.abb.2012.03.013

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  • Comparative analysis of carbohydrate-binding specificities of two anti-glycogen monoclonal antibodies using ELISA and surface plasmon resonance Reviewed

    Sachiko Nakamura-Tsuruta, Michiko Yasuda, Toshiyuki Nakamura, Eri Shinoda, Takashi Furuyashiki, Ryo Kakutani, Hiroki Takata, Yoji Kato, Hitoshi Ashida

    CARBOHYDRATE RESEARCH   350   49 - 54   2012.3

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    DOI: 10.1016/j.carres.2011.12.029

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  • Accumulation of orally administered quercetin in brain tissue and its antioxidative effects in rats Reviewed

    Akari Ishisaka, Satomi Ichikawa, Hiroyuki Sakakibara, Mariusz K. Piskula, Toshiyuki Nakamura, Yoji Kato, Mikiko Ito, Ken-ichi Miyamoto, Akira Tsuji, Yoshichika Kawai, Junji Terao

    FREE RADICAL BIOLOGY AND MEDICINE   51 ( 7 )   1329 - 1336   2011.10

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    DOI: 10.1016/j.freeradbiomed.2011.06.017

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  • Possible Evidence of Contamination by Catechins in Deconjugation Enzymes from Helix pomatia and Abalone entrails Reviewed

    Toshiyuki Nakamura, Ryohei Tanaka, Hitoshi Ashida

    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY   75 ( 8 )   1506 - 1510   2011.8

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  • alpha-Oligoglucosylation of a sugar moiety enhances the bioavailability of quercetin glucosides in humans Reviewed

    Kaeko Murota, Namiko Matsuda, Yasuaki Kashino, Yutaka Fujikura, Toshiyuki Nakamura, Yoji Kato, Ryosuke Shimizu, Syuji Okuyama, Hisashi Tanaka, Takatoshi Koda, Keiko Sekido, Junji Terao

    ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS   501 ( 1 )   91 - 97   2010.9

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    DOI: 10.1016/j.abb.2010.06.036

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  • Immunochemical Detection of Food-Derived Isothiocyanate as a Lysine Conjugate Reviewed

    Toshiyuki Nakamura, Noritoshi Kitamoto, Toshihiko Osawa, Yoji Kato

    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY   74 ( 3 )   536 - 540   2010.3

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    DOI: 10.1271/bbb.90728

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  • Covalent Modification of Lysine Residues by Allyl Isothiocyanate in Physiological Conditions: Plausible Transformation of Isothiocyanate from Thiol to Amine Reviewed

    Toshiyuki Nakamura, Yoshichika Kawai, Noritoshi Kitamoto, Toshihiko Osawa, Yoji Kato

    CHEMICAL RESEARCH IN TOXICOLOGY   22 ( 3 )   536 - 542   2009.3

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    DOI: 10.1021/tx8003906

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  • Quantification of Modified Tyrosines in Healthy and Diabetic Human Urine using Liquid Chromatography/Tandem Mass Spectrometry Reviewed

    Yoji Kato, Natsuko Dozaki, Toshiyuki Nakamura, Noritoshi Kitamoto, Akihiro Yoshida, Michitaka Naito, Masayasu Kitamura, Toshihiko Osawa

    JOURNAL OF CLINICAL BIOCHEMISTRY AND NUTRITION   44 ( 1 )   67 - 78   2009.1

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    DOI: 10.3164/jcbn.08-185

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Books

  • ポリフェノールの科学 : 基礎化学から健康機能まで

    寺尾, 純二, 下位, 香代子, 越阪部, 奈緒美, 榊原, 啓之, 中村, 宜督, 三好, 規之, 室田, 佳恵子

    朝倉書店  2023.11  ( ISBN:9784254103038

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MISC

  • 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

    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

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  • Difference in antioxidant capacity of rice extracts among rice categories and degree of milling and processing

    Hongyan Wu, Miho Hirooka, Toshiyuki Nakamura, Shintaro Munemasa, Yoshiyuki Murata, Yoshimasa Nakamura

    The 7th International Conference on Food Factors (ICoFF)proceedings   2019.12

Research Projects

  • Novel signal molecules mediating guard-cell signaling

    Grant number:25H00921  2025.04 - 2030.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    村田 芳行, 宗正 晋太郎, 中村 俊之

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    Grant amount:\46150000 ( Direct expense: \35500000 、 Indirect expense:\10650000 )

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  • Establishment of Molecular Basis of Aldehyde Paradox and its Control by Food Ingredients

    Grant number:23K26854  2023.04 - 2027.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    中村 宜督, 松本 明子, 佐藤 あやの, 中村 俊之

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    Grant amount:\18590000 ( Direct expense: \14300000 、 Indirect expense:\4290000 )

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  • 活性カルボニル種とグルタチオンによる気孔閉口信号伝達の二次元的制御

    Grant number:22H02303  2022.04 - 2026.03

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    村田 芳行, 宗正 晋太郎, 中村 俊之

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    Grant amount:\17810000 ( Direct expense: \13700000 、 Indirect expense:\4110000 )

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  • 活性カルボニル種とグルタチオンによる気孔閉口信号伝達の二次元的制御

    Grant number:23K23569  2022.04 - 2026.03

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    村田 芳行, 宗正 晋太郎, 中村 俊之

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    Grant amount:\17810000 ( Direct expense: \13700000 、 Indirect expense:\4110000 )

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  • 生体利用性を考慮した植物性食品成分の機能性評価

    Grant number:21K11676  2021.04 - 2024.03

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    中村 俊之

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    Grant amount:\4160000 ( Direct expense: \3200000 、 Indirect expense:\960000 )

    植物性食品成分の多くは植物中では配糖体として存在しており、摂取した配糖体は小腸や大腸で代謝変換を受け生体内では代謝物として存在している。そのため、それらの有効性は抱合代謝物や分解代謝物の寄与が考えられるが、多くの抱合/分解代謝物の生理活性は不明である。加えて、食品成分の生体利用性は、食品の単独摂取と日常的な食生活の形態である複数同時摂取で異なる。しかしながら、複数同時摂取でのそれらの代謝変化を評価した報告はない。そこで本申請研究では、植物性食品成分の複数同時摂取がそれらの生体利用性に及ぼす影響を検討するとともに、食品成分の代謝変換物の機能性を評価する。これらの研究を通して、機能性食品成分の実質的な有効性を評価し、健康増進・維持への貢献を目指す。
    本年度は、代表的なフラボノイドであるケルセチンに着目し(1)DPPHラジカル消去活性ならびにORAC(Oxygen Radical Absorbance Capacity)法によりケルセチン代謝物の抗酸化能を評価した。その結果、ケルセチン>>ケルセチングルクロン酸抱合体>硫酸抱合体の順に抗酸化能を示した。(2)ケルセチン代謝物による抗酸化酵素Heme oxygenase-1(HO-1)の遺伝子発現を評価した。その結果、ケルセチン代謝物処理によりHO-1遺伝子の有為な発現上昇が認められた。
    (3)ケルセチンとその他食品成分の同時摂取がケルセチンの吸収に及ぼす影響を評価した。その結果、ケルセチン単独投与に比べ、他成分との同時摂取により総ケルセチン吸収量の変化が認められた。

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  • Lymphatic transport of dietary flavonoids: elucidation of its driving force and physiological roles

    Grant number:20H04104  2020.04 - 2024.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    室田 佳恵子, 高橋 信之, 早坂 晴子, 中村 俊之

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    フラボノイドは代表的な機能性食品成分であり、その生体利用性を明らかにすることは作用機序解明に重要である。本研究においては、リンパカニュレーションラットを用いて、どのような構造を持つフラボノイドがリンパ系に輸送されやすいのかを明らかにし、またフラボノイドのリンパ輸送の生理的意義を解明することを目的としている。フラボノイドの構造とリンパ輸送の関係性については、血漿/リンパ液の分配比がフラボノイドの基本骨格により異なることが示唆されている。この時、通常脂質吸収経路としての役割を果たすリンパ液への輸送であるが、食品中に存在するフラボノイドの極性はリンパ輸送の要因とはならないと考えられた。現在さらに種類を増やして構造輸送相関を検討している。また、一部の配糖体が直接リンパ液に出現することを明らかにした。リンパ系へ輸送されたフラボノイドの生理的役割については、既にリンパ液へ輸送されることを明らかにしているケルセチンとアピゲニンを中心に影響を調べたところ、リンパ管内皮細胞における炎症時の応答に対する抑制効果はフラボノイドの構造により異なることが示唆された。しかし現時点では、どのような分子内構造が活性発揮に重要かは明確でなく、特にフラボノイド基本骨格と抱合代謝による活性変化に着目しながら、引き続き検討している。また、リンパ液へ輸送されるフラボノイドの標的と考えられるリンパ節におけるフラボノイドの作用を探索するため、樹状細胞を用いた実験系の確立を開始した。

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  • Influence of genetic background unique to the Japanese on metabolism and physiological activities of functional food components

    Grant number:20H02933  2020.04 - 2023.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    中村 宜督, 松本 明子, 佐藤 あやの, 中村 俊之, 増田 潤子

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    Grant amount:\18070000 ( Direct expense: \13900000 、 Indirect expense:\4170000 )

    本申請課題では、代表的な機能性食品成分であるケルセチンとイソチオシアネート(ITC)に注目して、日本人特有の遺伝的背景であるALDH2変異が機能性食品成分の代謝・生理機能に与える影響を明らかにすることを目的とした。以下に、本年度の具体的な成果を示す。
    1)昨年度確立した薬物代謝酵素活性が高い肝臓培養細胞モデル(マウスHepa1c1c7)を用いて、ケルセチン腸内細菌代謝物の3-ヒドロキシフェニル酢酸(OPAC)にALDH活性増強作用及びアセトアルデヒド毒性に対する保護作用を見出した。OPACは抗酸化作用を示さないだけでなく、Nrf2も活性化せず、AhR依存的に総ALDH活性を増強することにより、アセトアルデヒド誘導細胞毒性を緩和したことから、ポリフェノールのなかでも非常にユニークな生理活性発現機構を持つことが示唆された。
    2)皮膚培養細胞モデル(ヒトHaCaT)を用いて、ケルセチンのアセトアルデヒドに対する保護作用とそのメカニズムを明らかにした。ケルセチンは第2相薬物代謝酵素群や細胞内グルタチオン量を上方調節することで細胞内抗酸化活性を増強し、アセトアルデヒド誘導酸化ストレスを軽減することが示唆された。
    3)肝臓培養細胞モデルを用いて、米抽出物とα-トコフェロールの細胞内抗酸化活性の増強作用を見出した。抽出物レベルでは、白米に玄米と同等の抗酸化潜在能力があることが示唆された。
    4)ALDH2ノックアウトマウスとLC-MS/MSを用いて、ケルセチン摂取後のケルセチン代謝物(グルクロン酸/硫酸抱合体)の血中動態を解析したところ、野生型とほぼ同様であることを観察した。

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  • Identification of biomolecules controlled by food ingredients and elucidation of their functions

    Grant number:17H04725  2017.04 - 2021.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (A)

    Nakamura Toshiyuki

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    Grant amount:\25740000 ( Direct expense: \19800000 、 Indirect expense:\5940000 )

    We investigated the interaction of benzyl isothiocyanate (BITC) with biomolecules. BITC modified ethanolamine was detected from cultured cells after treatment of BITC. It was suggested that phosphatidylethanolamine modified with BITC was degraded by phosphatases. In addition, some proteins were modified with BITC. A correlation was found between the activity and BITC modification in one of the modified proteins, suggesting that BITC directly regulated the protein activity via the modification.

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  • Identification and characterization of phytochemical-targeted genes using a genome wide yeast screening system

    Grant number:17H03818  2017.04 - 2020.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Nakamura Yoshimasa

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    Grant amount:\17680000 ( Direct expense: \13600000 、 Indirect expense:\4080000 )

    We identified 12 resistance genes against benzyl isothiocyanate (BITC) from total 6000 yeast genes using a new evaluation model system, the budding yeast gene tug-of-war method (gTOW method). A human cancer cell line stably overexpressing the human homologue (Mis12) of BITC resistance gene MTW1 was established, which showed high resistance to BITC. Mis12 knockdown conversely increased sensitivity. It was also suggested that the expression of Mis12 is down-regulated by BITC via post-translational modification, which contributes to suppressive effect of BITC on colon cancer cell proliferation by enhancing the sensitivity to apoptosis in a cell cycle-dependent manner.

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  • Authenticity of premium honeys by multi-component analysis to prevent food disguise

    Grant number:17H01960  2017.04 - 2020.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Kato Yoji

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    Grant amount:\18330000 ( Direct expense: \14100000 、 Indirect expense:\4230000 )

    We ivestigate the contents of 70 honey samples from domestic and foregin coutries using liquid chromatography-precise mass spectometry to apply the possible authentication of origin of the honey. When the changes in contents by heating were analyzed by chemical and immunochemical approaches, we have found two unstable chemicals; One chemical is vapoured and the other is decreased by amino-carbonyl reaction. In culture cells, hydrophobic chemicals are incorporated and then metabolized to water-soluble (hydrophilic) metabolites by intracellular esterase and so on. The hydrophilic metabolite is accumulated in a cell for a while. The accumulation may induce some functionality in the cell.

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  • Constitutive and structural changes of membrane microdomains and lipid accumulation control by food chemicals

    Grant number:16K14928  2016.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Challenging Exploratory Research

    NAKAMURA Yoshimasa, LIU Xiaoyang, YANG Qifu, LIANG Ying, SASAKI Ikumi

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    Grant amount:\3510000 ( Direct expense: \2700000 、 Indirect expense:\810000 )

    The purpose of this study was to clarify the physiological significance of the constitutive and structural changes of membrane microdomains by food chemicals through studies on their modulation of insulin signaling activation and its consequent phenomena such as the cancer cell survival and lipid accumulation. We identified benzyl isothiocyanate (BITC) as an insulin signal modulator. BITC enhanced glucose uptake in adipocytes as well as the survival pathway and autophagy in colorectal cancer cells, possibly through the activation of insulin signaling. The anti-cancer effect of BITC was potentiated by insulin signaling inhibitors as well as methyl-β-cyclodextrin, a depleting agent of membrane cholesterol.

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  • Investigation of mechanism of dietary ligands-TRPA1 interactions

    Grant number:15K16212  2015.04 - 2017.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    NAKAMURA Toshiyuki

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    Grant amount:\4030000 ( Direct expense: \3100000 、 Indirect expense:\930000 )

    We investigated the interaction between TRPA1 and food compounds. We indicated some novel agonists of TRPA1 such as Kaempferol and Myricetin. In addition, the agonistic activities of several major quercetin glycosides and metabolites towards TRPA1 were also evaluated. Methylated quercetin activated TRPA1 receptor. To identify the site of interaction of these flavonoids and TRPA1, we attempted to prepare the monoclonal antibodies to flavonoids. We developed a novel monoclonal antibody using dihydroxyphenylacetic acid as an immunogen.

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  • 「冷え」改善効果を有する食品の評価系の開発

    Grant number:15K00826  2015.04 - 2016.03

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    渡辺 達夫, 中村 俊之

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    Grant amount:\4550000 ( Direct expense: \3500000 、 Indirect expense:\1050000 )

    冬期や夏期の空調下において、手や足の指先などが冷える、いわゆる「冷え」は、日本では冷え症などと言われていて、QOLを低下させ、多くのヒトを悩ませている。伝承的に体を温めるといわれている食品が複数存在するが、その中のショウガやヒハツなどの一部の食品は、摂取することによってヒトにおいて指先の温度上昇をもたらし、「冷え」の解消に役立つ食品と考えられているが、その作用機構並びに作用成分は不明である。そこで、本研究では、まず、ヒトでの「冷え」を評価する実験系をマウスにて構築し、次いで、作用機構と作用成分の解明につなげることを目的とした。
    マウスを用いて、無麻酔にて赤外線サーモグラフィー装置にて表面温度を測定する実験系にて「冷え」評価系の構築を試みた。マウスをいれる撮影容器のサイズ・形状・素材等を種々検討し、軽度の寒冷負荷下で、被検試料を投与後にマウスを無麻酔試験用撮影台にのせ、マウスの尾部温度への試料投与の影響を検討する系で再現性のある実験データが得られた。ついで、「冷え」の改善効果が認められている食品成分としてショウガとヒハツの抽出物をそれぞれ投与した結果、ヒトの指先温と同様にマウスの尾温の寒冷負荷による低下をこれらの食品抽出物が抑制した。これらのことから、本実験系が、少なくともヒト指先血流改善効果の検証に用いうることが推察された。
    さらに、ショウガやヒハツ中の有効成分候補化合物をマウスでの実験系に供し、ヒハツではヒハツ中の辛味化合物が有効成分であること、ショウガではショウガ辛味化合物は活性成分ではあるものの辛味化合物のみではショウガ抽出物のマウス尾温上昇活性は説明がつかないことを見出した。ヒハツ中の辛味化合物によるマウス尾温の低減抑制活性へのTRPV1の関与を調べたところ、TRPV1アンタゴニストで辛味化合物による活性は消失し、ヒハツに関してはTRPV1の関与することが示された。

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  • Evaluation of the significance of prenylation on the physiological function of flavonoids

    Grant number:25292075  2013.04 - 2016.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    TERAO Junji, MUKAI Rie

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    Grant amount:\14040000 ( Direct expense: \10800000 、 Indirect expense:\3240000 )

    This study was aimed to evaluate the effect of prenylation on the functionality of flavonoids from the viewpoint of structure-activity relationship. The compounds used were 6-prenylquercetin (6-PQ), 5-PQ and 8-PQ. We found that hydrophobicity is changed depending on the positon of prenyl group in the flavonoid structure. 6-PQ with the highest hydrophobicity showed the highest induction of heme oxygenase-1 in accordance with the highest efficiency of cellular uptake in human blood endothelial cells. The result that quercetin modulated the vascular function of caveolin-1 in the cells may indicate that caveolin-1 and caveolae are potential targets for the action of prenylated flavonoids

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  • Seminar in Food Biochemistry (2023academic year) Late  - その他

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  • Current Topics in Food Biochemistry (2023academic year) Prophase  - その他

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