Updated on 2024/01/18

写真a

 
KUBOTA Takaaki
 
Organization
Faculty of Medicine, Dentistry and Pharmaceutical Sciences Professor
Position
Professor
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Degree

  • 2002, Ph. D. (Pharmaceutical Sciences), Hokkaido University ( 2002.3   Hokkaido University )

Research Interests

  • 立体化学

  • アルカロイド

  • 海洋由来真菌

  • アクチン

  • チューブリン

  • 分子標的

  • リード化合物

  • Natural Products Chemistry

  • 天然物有機化学

  • がん分子標的

  • がん治療

  • バイオプローブ

  • 殺細胞活性

  • 医薬リード

  • 海洋天然物

  • イエジマリド

  • 天然薬物

  • 天然物ライブラリー

  • 機能性天然分子

  • 海洋生物

  • ポリケチド合成酵素

  • 生物・生体工学

  • 天然資源

Research Areas

  • Life Science / Bioorganic chemistry

  • Nanotechnology/Materials / Structural organic chemistry and physical organic chemistry

  • Nanotechnology/Materials / Chemistry and chemical methodology of biomolecules

  • Life Science / Pharmaceutical chemistry and drug development sciences

Education

  • Hokkaido University   大学院薬学研究科   博士後期課程

    1999.4 - 2002.3

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    Country: Japan

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  • Hokkaido University   大学院薬学研究科   修士課程

    1997.4 - 1999.3

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    Country: Japan

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  • Tokyo University of Science   薬学部   製薬学科

    1992.4 - 1996.3

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    Country: Japan

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Research History

  • Okayama University   Faculty of Medicine , Dentistry, and Pharmaceutical Sciences   Professor

    2021.4

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  • Okayama University   Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences   Professor

    2020.11 - 2021.3

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  • Showa Pharmaceutical University   薬学部   Professor

    2015.4 - 2020.10

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  • Hokkaido University   大学院薬学研究院   Associate Professor

    2010.4 - 2015.3

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  • Hokkaido University   大学院先端生命科学研究院   Associate Professor

    2009.2 - 2010.3

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  • Hokkaido University   大学院薬学研究院   Associate Professor

    2008.9 - 2009.1

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  • Hokkaido University   大学院薬学研究院   Lecturer

    2006.4 - 2008.8

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  • Hokkaido University   大学院薬学研究科   Lecturer

    2005.4 - 2006.3

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  • Hokkaido University   大学院薬学研究科   Research Associate

    2005.2 - 2005.3

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  • University of Washington   Department of Chemistry   Research Associate

    2003.4 - 2005.1

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  • Japan Society for Promotion of Science   Postdoctoral Fellowships of Japan Society for the Promotion of Science

    2002.4 - 2003.3

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  • Japan Society for Promotion of Science   Postdoctoral Fellowships of Japan Society for the Promotion of Science

    2001.4 - 2002.3

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Professional Memberships

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Committee Memberships

  • 日本薬学会   中国四国支部大学選出幹事  

    2023.2   

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    Committee type:Academic society

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  • 日本薬学会   代議員  

    2023.2   

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    Committee type:Academic society

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  • 日本薬学会   生薬天然物部会常任世話人  

    2021.4   

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  • 日本生薬学会   関西支部委員  

    2021.4   

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  • 日本薬学会   関東支部執行部  

    2020.3 - 2021.2   

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  • 日本生薬学会   財務理事  

    2018.4 - 2022.3   

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    Committee type:Academic society

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  • 日本生薬学会   学会誌編集委員会編集副委員長  

    2018   

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  • 日本生薬学会   財務理事補佐  

    2017   

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  • 日本生薬学会   学会誌編集委員会委員  

    2016 - 2017   

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  • 日本生薬学会   代議員  

    2016 - 2017   

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    Committee type:Academic society

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  • 日本生薬学会   北海道支部庶務  

    2014   

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  • 日本生薬学会   北海道支部監事  

    2012 - 2013   

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  • 日本生薬学会   北海道支部委員  

    2010 - 2011   

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  • 日本生薬学会   北海道支部監事  

    2008 - 2009   

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    Committee type:Academic society

    日本生薬学会

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  • 日本薬学会   代議員  

    2008 - 2009   

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  • 日本薬学会   北海道支部庶務幹事  

    2008   

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    Committee type:Academic society

    日本薬学会

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  • 日本薬学会   トピックス専門小委員  

    2007 - 2008   

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    Committee type:Academic society

    日本薬学会

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  • 日本薬学会   北海道支部幹事  

    2007   

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    Committee type:Academic society

    日本薬学会

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  • 日本生薬学会   北海道支部庶務  

    2006 - 2007   

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    Committee type:Academic society

    日本生薬学会

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Papers

  • Evaluating the activity of N-89 as an oral antimalarial drug Reviewed

    Nagwa S. M. Aly, Hiroaki Matsumori, Thi Quyen Dinh, Akira Sato, Shin-ichi Miyoshi, Kyung-Soo Chang, Hak Sun Yu, Takaaki Kubota, Yuji Kurosaki, Duc Tuan Cao, Gehan A. Rashed, Hye-Sook Kim

    Parasites, Hosts and Diseases   61 ( 3 )   282 - 291   2023.8

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    Publishing type:Research paper (scientific journal)   Publisher:Korean Society for Parasitology  

    Despite the recent progress in public health measures, malaria remains a troublesome disease that needs to be eradicated. It is essential to develop new antimalarial medications that are reliable and secure. This report evaluated the pharmacokinetics and antimalarial activity of 1,2,6,7-tetraoxaspiro[7.11]nonadecane (N-89) using the rodent malaria parasite Plasmodium berghei in vivo. After a single oral dose (75 mg /kg) of N-89, its pharmacokinetic parameters were measured, and t<sub>1/2</sub> was 0.97 h, T<sub>max</sub> was 0.75 h, and bioavailability was 7.01%. A plasma concentration of 8.1 ng/ml of N-89 was maintained for 8 h but could not be detected at 10 h. The dose inhibiting 50% of parasite growth (ED<sub>50</sub>) and ED<sub>90</sub> values of oral N-89 obtained following a 4-day suppressive test were 20 and 40 mg/kg, respectively. Based on the plasma concentration of N-89, we evaluated the antimalarial activity and cure effects of oral N-89 at a dose of 75 mg/kg 3 times daily for 3 consecutive days in mice harboring more than 0.5% parasitemia. In all the N-89- treated groups, the parasites were eliminated on day 5 post-treatment, and all mice recovered without a parasite recurrence for 30 days. Additionally, administering oral N-89 at a low dose of 50 mg/kg was sufficient to cure mice from day 6 without parasite recurrence. This work was the first to investigate the pharmacokinetic characteristics and antimalarial activity of N-89 as an oral drug. In the future, the following steps should be focused on developing N-89 for malaria treatments; its administration schedule and metabolic pathways should be investigated.

    DOI: 10.3347/phd.23044

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  • Zamamiphidins B and C, Manzamine-Related Alkaloids from an Amphimedon sp. Marine Sponge Collected in Okinawa Reviewed International journal

    Shin-ichiro Kurimoto, Shoichi Suzuki, Mayumi Ueno, Jane Fromont, Jun’ichi Kobayashi, Takaaki Kubota

    Journal of Natural Products   85 ( 9 )   2226 - 2231   2022.9

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

    Zamamiphidins B (1) and C (2), two new manzamine-related alkaloids with an unprecedented fused diazahexacyclic ring system, were isolated from an Amphimedon sp. marine sponge collected in Okinawa. The structures of zamamiphidins B (1) and C (2) including the relative configurations were elucidated on the basis of spectroscopic data.

    DOI: 10.1021/acs.jnatprod.2c00395

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  • Ma'edamines E and F, rare bromotyrosine alkaloids possessing a 1,2,3,5-tetrasubstituted pyridinium moiety from an Okinawan marine sponge Suberea sp. Reviewed

    Shin ichiro Kurimoto, Ayano Okamoto, Satsuki Seino, Jane Fromont, Jun'ichi Kobayashi, Takaaki Kubota

    Tetrahedron Letters   103   2022.8

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    Two new bromotyrosine alkaloids, ma'edamines E (1) and F (2), were isolated from an Okinawan marine sponge Suberea sp., and their structures were elucidated by the analyses of spectroscopic (UV, IR, and NMR) and spectrometric (MS) data. Ma'edamines E (1) and F (2) are the second and third examples of natural products possessing an N-alkyl-3,5-diethyl-2-propylpyridinium moiety. Ma'edamine F (2) is the first bromotyrosine alkaloid having both pyridinium and quaternary ammonium moieties. Ma'edamines E (1) and F (2) showed moderate cytotoxicity against L1210 murine leukemia cells in vitro.

    DOI: 10.1016/j.tetlet.2022.153985

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  • Teuchamaedol A, a new neo-clerodane diterpenoid from the aerial parts of Teucrium chamaedrys Reviewed

    Shin-ichiro Kurimoto, Koji Wakabayashi, Yu F. Sasaki, Takanori Nakamura, Takaaki Kubota

    TETRAHEDRON LETTERS   100   2022.6

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

    A new neo-clerodane diterpenoid, teuchamaedol A (1) was isolated from the EtOAc-soluble materials of the aerial parts of Teucrium chamaedrys. The structure of 1 was elucidated on the basis of spectral data. The absolute configuration of 1 was determined by modified Mosher's method. Teuchamaedol A (1) is the first neo-clerodane diterpenoid possessing a tetrahydrofuran moiety without additional oxygen function. (C) 2022 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.tetlet.2022.153890

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  • Macrocarquinoid D, New Meroterpenoid from Brown Alga, Sargassum macrocarpum Reviewed

    Mitsuhiro Sekiguchi, Seiya Shinoda, Shin-ichiro Kurimoto, Takaaki Kubota

    HETEROCYCLES   104 ( 6 )   1141 - 1141   2022

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    Publishing type:Research paper (scientific journal)   Publisher:The Japan Institute of Heterocyclic Chemistry  

    DOI: 10.3987/com-22-14651

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  • Macrocarquinoids A–C, new meroterpenoids from Sargassum macrocarpum Reviewed

    Hiromi Niwa, Shin ichiro Kurimoto, Takaaki Kubota, Mitsuhiro Sekiguchi

    Journal of Natural Medicines   75 ( 1 )   194 - 200   2021.1

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

    The production and accumulation of advanced glycation end products (AGEs) have been implicated in diabetes and diabetic complication. This study was conducted as a search for an AGE inhibitor from brown alga,Sargassum macrocarpum.Separation and purification were performed using AGEs inhibitory activity as an index, yielding isolation of 11 meroterpenoids, of which 3 were new compounds: macrocarquinoids A (1), B (6), and C (9). Their structures were elucidated using NMR spectral analysis with 2D techniques. All tested compounds showed AGEs inhibitory activity. Particularly, macrocarquinoid C (9) possessed the strongest activity (IC50: 1.0 mM) of isolated compounds. This activity was stronger than that of aminoguanidine (positive control).[GRAPHICS].

    DOI: 10.1007/s11418-020-01449-y

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  • Kamiohnoyneosides A and B, two new polyacetylene glycosides from flowers of edible Chrysanthemum "Kamiohno" Reviewed

    Shin ichiro Kurimoto, Hiroki Fujita, Satomi Kawaguchi, Yu F. Sasaki, Takanori Nakamura, Takaaki Kubota

    Journal of Natural Medicines   75 ( 1 )   167 - 172   2021.1

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

    Two new polyacetylene glycosides, kamiohnoyneosides A and B, were isolated from the flowers of edible Chrysanthemum "Kamiohno", along with a known polyacetylene glycoside and two known monoterpene glycosides. The structures of new compounds were elucidated on the basis of spectroscopic data. Kamiohnoyneoside A and three known compounds moderately inhibited formation of Nε-(carboxymethyl)lysine, one of the representative advanced glycation endproducts.

    DOI: 10.1007/s11418-020-01443-4

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  • Integrated omics unveil the secondary metabolic landscape of a basal dinoflagellate Reviewed

    Girish Beedessee, Takaaki Kubota, Asuka Arimoto, Koki Nishitsuji, Ross F. Waller, Kanako Hisata, Shinichi Yamasaki, Noriyuki Satoh, Jun’ichi Kobayashi, Eiichi Shoguchi

    BMC Biology   18 ( 1 )   2020.12

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    Background: Some dinoflagellates cause harmful algal blooms, releasing toxic secondary metabolites, to the detriment of marine ecosystems and human health. Our understanding of dinoflagellate toxin biosynthesis has been hampered by their unusually large genomes. To overcome this challenge, for the first time, we sequenced the genome, microRNAs, and mRNA isoforms of a basal dinoflagellate, Amphidinium gibbosum, and employed an integrated omics approach to understand its secondary metabolite biosynthesis. Results: We assembled the ~ 6.4-Gb A. gibbosum genome, and by probing decoded dinoflagellate genomes and transcriptomes, we identified the non-ribosomal peptide synthetase adenylation domain as essential for generation of specialized metabolites. Upon starving the cells of phosphate and nitrogen, we observed pronounced shifts in metabolite biosynthesis, suggestive of post-transcriptional regulation by microRNAs. Using Iso-Seq and RNA-seq data, we found that alternative splicing and polycistronic expression generate different transcripts for secondary metabolism. Conclusions: Our genomic findings suggest intricate integration of various metabolic enzymes that function iteratively to synthesize metabolites, providing mechanistic insights into how dinoflagellates synthesize secondary metabolites, depending upon nutrient availability. This study provides insights into toxin production associated with dinoflagellate blooms. The genome of this basal dinoflagellate provides important clues about dinoflagellate evolution and overcomes the large genome size, which has been a challenge previously.

    DOI: 10.1186/s12915-020-00873-6

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  • The manzamine alkaloids Reviewed International journal

    Takaaki Kubota, Shin ichiro Kurimoto, Jun'ichi Kobayashi

    Alkaloids: Chemistry and Biology   84   1 - 124   2020

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    Language:English   Publishing type:Part of collection (book)  

    The manzamine alkaloids are absolutely one of the most fascinating marine natural products. The representative manzamine alkaloids, manzamines A-C, were isolated from a marine sponge Haliclona sp. collected off Cape Manzamo, Okinawa, Japan. The manzamine alkaloids are a unique class of alkaloids possessing a characteristic heterocyclic system, and exhibit a diverse range of bioactivities including cytotoxicity, antimicrobial activity, antimalarial activity, antiviral and antiinflammatory activities, antiinsecticidal activity, and proteasome inhibitory activity. About 100 manzamine alkaloids have been isolated from more than 16 species of marine sponges belonging to 5 families. The unusual ring systems, an intriguing suggested biogenetic pathway, and promising biological activities of manzamine alkaloids have attracted great interest as challenging targets for the total synthesis. This review is the continuation of the previous review published in volume 60 of The Alkaloids and covers isolation, structure elucidation, biosynthesis and biogenesis, chemical synthesis, and biological activity of manzamine alkaloids reported from 2003 to 2018.

    DOI: 10.1016/bs.alkal.2020.03.001

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  • Ma'edamines C and D, New Bromotyrosine Alkaloids Possessing a Unique Tetrasubstituted Pyridinium Moiety from an Okinawan Marine Sponge Suberea sp. Reviewed

    Shin ichiro Kurimoto, Satsuki Seino, Jane Fromont, Jun'ichi Kobayashi, Takaaki Kubota

    Organic Letters   21 ( 21 )   8824 - 8826   2019.11

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    Publishing type:Research paper (scientific journal)   Publisher:American Chemical Society ({ACS})  

    Two new bromotyrosine alkaloids, ma'edamines C and D, were isolated from an Okinawan marine sponge Suberea sp. The structures of ma'edamines C and D were elucidated on the basis of spectroscopic data. Ma'edamines C and D were the first natural products possessing a unique tetrasubstituted pyridinium moiety such as N-alkyl-3,5-diethyl-2-propylpyridinium and N-alkyl-3,5-diethyl-4-propylpyridinium, respectively. Ma'edamines C and D exhibited moderate cytotoxicity against murine leukemia cell line L1210 in vitro.

    DOI: 10.1021/acs.orglett.9b03457

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  • Symbiodinolactone A, a new 12-membered macrolide from symbiotic marine dinoflagellate Symbiodinium sp. Reviewed

    Shin ichiro Kurimoto, Yurika Iinuma, Jun'ichi Kobayashi, Takaaki Kubota

    Tetrahedron Letters   59 ( 51 )   4496 - 4499   2018.12

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier {BV}  

    A new 12-membered macrolide, symbiodinolactone A, was isolated from the culture broth of symbiotic marine dinoflagellate Symbiodinium sp. The gross structure of symbiodinolactone A was elucidated by spectroscopic analyses, and the relative configuration was elucidated by the J-based configuration analysis and density-functional theory calculations. Symbiodinolactone A is the new 12-membered macrolide possessing an E double bond between C-4 and C-5, a branched methyl group at C-7, and a 1,2,3-trihydroxybutyl group at C-11. Symbiodinolactone A is the first usual size macrolide and the first non-nitrogen-containing macrolide from dinoflagellate Symbiodinium sp. Symbiodinolactone A might be generated by the unexplained dinoflagellate polyketide biosynthetic machinery.

    DOI: 10.1016/j.tetlet.2018.11.018

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  • Ishigadine A, a new canthin-6-one alkaloid from an Okinawan marine sponge Hyrtios sp. Reviewed

    Hideaki Takahashi, Shin ichiro Kurimoto, Jun'ichi Kobayashi, Takaaki Kubota

    Tetrahedron Letters   59 ( 51 )   4500 - 4502   2018.12

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    Publishing type:Research paper (scientific journal)   Publisher:Elsevier {BV}  

    A new indole alkaloid with the canthin-6-one skeleton, ishigadine A, has been isolated from an Okinawan marine sponge Hyrtios sp. The structure of ishigadine A was elucidated on the basis of spectroscopic analyses. Ishigadine A is a new canthin-6-one alkaloid possessing a hydroxy group, a 1,3-dimethyl-4-methylthioimidazolium, and a 1-propylguanidine. Ishigadine A is the third canthin-6-one alkaloid from sponges. Ishigadine A might be generated from L-arginine, L-histidine, and L-tryptophan. Ishigadine A exhibited moderate cytotoxicity against L1210 murine leukemia cells.

    DOI: 10.1016/j.tetlet.2018.11.019

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  • Ceratinadins E and F, new bromotyrosine alkaloids from an Okinawan marine sponge Pseudoceratina sp. Reviewed International journal

    Shin Ichiro Kurimoto, Taito Ohno, Rei Hokari, Aki Ishiyama, Masato Iwatsuki, Satoshi Ōmura, Jun’ichi Kobayashi, Takaaki Kubota

    Marine Drugs   16 ( 12 )   463   2018.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:MDPI} {AG  

    Two new bromotyrosine alkaloids, ceratinadins E (1) and F (2), were isolated from an Okinawan marine sponge Pseudoceratina sp. as well as a known bromotyrosine alkaloid, psammaplysin F (3). The gross structures of 1 and 2 were elucidated on the basis of spectroscopic data. The absolute configurations of 1 and 2 were assigned by comparison of the NMR and ECD data with those of a known related bromotyrosine alkaloid, psammaplysin A (4). Ceratinadins E (1) and F (2) are new bromotyrosine alkaloids possessing an 8,10-dibromo-9-methoxy-1,6-dioxa-2-azaspiro[4.6]undeca-2,7,9-trien-4-ol unit with two or three 11-N-methylmoloka'iamine units connected by carbonyl groups, respectively. Ceratinadin E (1) exhibited antimalarial activities against a drug-resistant and a drug-sensitive strains of Plasmodium falciparum (K1 and FCR3 strains, respectively).

    DOI: 10.3390/md16120463

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  • New merosesquiterpenes from a Vietnamese marine sponge of Spongia sp. and their biological activities Reviewed

    Hien Minh Nguyen, Takuya Ito, Shin ichiro Kurimoto, Mika Ogawa, Nwet Nwet Win, Vo Quoc Hung, Hoai Thi Nguyen, Takaaki Kubota, Jun'ichi Kobayashi, Hiroyuki Morita

    Bioorganic and Medicinal Chemistry Letters   27 ( 14 )   3043 - 3047   2017.7

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

    The investigation of the Vietnamese marine sponge Spongia sp. led to the isolation of three new sesquiterpene phenols, langconols A-C (1-3), and one new sesquiterpene hydroxyquinone, langcoquinone C (4), together with two known meroterpenoids (5 and 6). Their structures were determined on the basis of spectroscopic analyses and comparisons with published data. Furthermore, the antibacterial assays of the isolates 1-6 suggested that 4 and 6 had significant antibacterial activities against Bacillus subtilis and Staphylococcus aureus, with MICs ranging from 6.25 to 25.0 mu M, while 1 and 3 possessed significant antibacterial activities against B. subtilis with MICs of 12.5 and 25.0 mu M, respectively. In contrast, cyto-toxic assays of the isolated compounds 1-6, as well as compounds 7-15 previously isolated from this sponge, indicated that 1 and the previously reported anti-B. subtilis and anti-S. aureus sesquiterpene phenol 9 lacked cytotoxic activities against three human cancer cell lines (A549, lung cancer; MCF7, breast cancer; HeLa, cervix cancer) and a human normal cell line (WI-38 fibroblast). (C) 2017 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.bmcl.2017.05.060

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  • Zamamidine D, a Manzamine Alkaloid from an Okinawan Amphimedon sp. Marine Sponge Reviewed

    Takaaki Kubota, Kenta Nakamura, Shin ichiro Kurimoto, Kanae Sakai, Jane Fromont, Tohru Gonoi, Jun’ichi Kobayashi

    Journal of Natural Products   80 ( 4 )   1196 - 1199   2017.4

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

    A new manzamine alkaloid, zamamidine D (1), was isolated from an Okinawan Amphimedon sp. marine sponge. The structure of zamamidine D (1) including the relative configuration was elucidated on the basis of spectroscopic data. Zamamidine D (1) is the first manzamine alkaloid possessing a 2,2'-methylenebistryptamine unit as the aromatic moiety instead of a beta-carboline unit. Zamamidine D (1) showed antimicrobial activity against several bacteria and fungi.

    DOI: 10.1021/acs.jnatprod.6b01110

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  • Stylissamide I, a new cyclic heptapeptide from an okinawan marine sponge Stylissa sp. Reviewed

    Takaaki Kubota, Kenta Nakamura, Shin Ichiro Kurimoto, Kanae Sakai, Jane Fromont, Tohru Gonoi, Jun'ichi Kobayashi

    Heterocycles   95 ( 2 )   799 - 806   2017.1

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

    A new cyclic heptapeptide, stylissamide I (1), was isolated from an Okinawan marine sponge Stylissa sp. The structure of stylissamide I (1) was elucidated to be cydo-(L-Tyr(1)-L-Tyr(2)-L-Tyr(3)-L-Pro(1)-L-Pro(2)-L-Val-L-Pro(3)) by extensive spectral analyses and Marfey's method. Stylissamide I (1) showed antifungal activity against Aspergillus niger.

    DOI: 10.3987/COM-16-S(S)45

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  • Hyrtinadines C and D, new azepinoindole-type alkaloids from a marine sponge Hyrtios sp. Reviewed

    Takaaki Kubota, Kenta Nakamura, Kanae Sakai, Jane Fromont, Tohru Gonoi, Jun'ichi Kobayashi

    Chemical and Pharmaceutical Bulletin   64 ( 7 )   975 - 978   2016.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHARMACEUTICAL SOC JAPAN  

    New bisindole alkaloids, hyrtinadines C (1) and D (2), have been isolated from an Okinawan marine sponge Hyrtios sp. The structures of hyrtinadines C (1) and D (2) were elucidated based on analyses of the spectral data. Hyrtinadines C (1) and D (2) were the relatively rare alkaloids possessing a 3,4-fused azepinoindole skeleton. Hyrtinadines C (1) and D (2) showed antimicrobial activity.

    DOI: 10.1248/cpb.c16-00201

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  • Biosynthetic study of amphidinin A and Amphidinolide P Reviewed

    Takaaki Kubota, Hayato Sato, Takahiro Iwai, Jun'ichi Kobayashi

    Chemical and Pharmaceutical Bulletin   64 ( 7 )   979 - 981   2016.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:PHARMACEUTICAL SOC JAPAN  

    The biogenetic origins of amphidinin A (1) and amphidinolide P (2) were investigated by feeding experiments with C-13-labeled acetates. C-13-NMR data of C-13-enriched samples revealed that the all carbons of 1 and 2 were derived from acetates. The polyketide chain of 1 was formed from one triketide chain, two diketide chains, and three unusual isolated C-1 units derived from C-2 of cleaved acetates, while the polyketide chain of 2 was formed from one pentaketide chain, two acetate units, and three unusual isolated C-1 units derived from C-2 of cleaved acetates. The all branched C-1 units of 1 and 2 were derived from C-2 of cleaved acetates.

    DOI: 10.1248/cpb.c16-00202

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  • Total Synthesis of the 7,10-Epimer of the Proposed Structure of Amphidinolide N, Part I: Synthesis of the C1-C13 Subunit Reviewed

    Koji Ochiai, Sankar Kuppusamy, Yusuke Yasui, Tsubasa Okano, Yasunobu Matsumoto, Nishant R. Gupta, Yohei Takahashi, Takaaki Kubota, Jun'ichi Kobayashi, Yujiro Hayashi

    Chemistry - A European Journal   22 ( 10 )   3282 - 3286   2016.3

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    Amphidinolide N, the structure of which has been recently revised, is a 26-membered macrolide featuring allyl epoxide and tetrahydropyran moieties with 13 chiral centers. Due to its challenging structure and extraordinary potent cytotoxicity, amphidinolide N is a highly attractive target of total synthesis. During our total synthesis studies of the 7,10-epimer of the proposed structure of amphidinolide N, we have synthesized the C1-C13 subunit enantio- and diastereoselectively. Key reactions include an l-proline catalyzed enantioselective intramolecular aldol reaction, Evans aldol reaction, Sharpless asymmetric epoxidation and Tamao-Fleming oxidation. To aid late-stage manipulations, we also developed the 4-(N-benzyloxycarbonyl-N-methylamino)butyryl group as a novel ester protective group for the C9 alcohol.

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  • Total Synthesis of the 7,10-Epimer of the Proposed Structure of Amphidinolide N, Part II: Synthesis of C17-C29 Subunit and Completion of the Synthesis Reviewed

    Koji Ochiai, Sankar Kuppusamy, Yusuke Yasui, Kenji Harada, Nishant R. Gupta, Yohei Takahashi, Takaaki Kubota, Jun'ichi Kobayashi, Yujiro Hayashi

    Chemistry - A European Journal   22 ( 10 )   3287 - 3291   2016.3

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    The total synthesis of 7,10-epimer of the proposed structure of amphidinolideN was accomplished. The requisite chiral C17-C29 subunit was assembled stereoselectively via Keck allylation, Shi epoxidation, diastereoselective 1,3-reduction, and a later oxidative synthesis of the THF framework. The C1-C13 and C17-C29 subunits were successfully coupled using a Enders RAMP linchpin as the C14-C16 three carbon unit, thereby controlling the chirality at C14 and C16. The labile allyl epoxy moiety was successfully constructed by Grieco-Nishizawa olefination at a final stage of the synthesis.

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  • Cyclopiazonic acid biosynthesis gene cluster gene cpaM is required for speradine A biosynthesis Reviewed

    Masafumi Tokuoka, Tomoki Kikuchi, Yasutomo Shinohara, Akifumi Koyama, Shin Ichiro Iio, Takaaki Kubota, Jun'ichi Kobayashi, Yasuji Koyama, Akira Totsuka, Hitoshi Shindo, Kazuo Sato

    Bioscience, Biotechnology and Biochemistry   79 ( 12 )   2081 - 2085   2015.12

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    Speradine A is a derivative of cyclopiazonic acid (CPA) found in culture of an Aspergillus tamarii isolate. Heterologous expression of a predicted methyltransferase gene, cpaM, in the cpa biosynthesis gene cluster of A. tamarii resulted in the speradine A production in a 2-oxoCPA producing A. oryzae strain, indicating cpaM is involved in the speradine A biosynthesis.

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  • Tyrokeradines G and H, new bromotyrosine alkaloids from an Okinawan Verongid sponge Reviewed

    Takaaki Kubota, Shinya Watase, Kanae Sakai, Jane Fromont, Tohru Gonoi, Jun'Ichi Kobayashi

    Bioorganic and Medicinal Chemistry Letters   25 ( 22 )   5221 - 5223   2015.11

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    Two new bromotyrosine alkaloids, tyrokeradines G (1) and H (2), have been isolated from an Okinawan marine sponge of the order Verongida. The structures of 1 and 2 were elucidated on the basis of spectroscopic data. Tyrokeradine G (1) is the first bromotyrosine alkaloid possessing a beta-alanine unit, while tyrokeradine H (2) is a rare bromotyrosine alkaloid possessing a N-substituted pyridinium ring. Tyrokeradines G (1) and H (2) showed antifungal activity. (C) 2015 Elsevier Ltd. All rights reserved.

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  • Amphidinin G, a putative biosynthetic precursor of amphidinin A from marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Takahiro Iwai, Haruaki Ishiyama, Kanae Sakai, Tohru Gonoi, Jun'Ichi Kobayashi

    Tetrahedron Letters   56 ( 8 )   990 - 993   2015.2

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    A new linear polyketide, amphidinin G (1), has been isolated from a symbiotic marine dinoflagellate Amphidinium sp. The planar structure of 1 was established mainly based on the 2D NMR data and the stereochemistry was elucidated by the combination off-value analysis, modified Mosher's method, and NMR chemical shift comparison with synthetic analogues. Amphidinin G (1) was expected to be a biosynthetic precursor of amphidinin A (2), a known linear dinoflagellate polyketide. Amphidinin G (1) showed antifungal activity against Trichophyton mentagrophytes. (C) 2015 Elsevier Ltd. All rights reserved.

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  • Iejimalide C is a potent V-ATPase inhibitor, and induces actin disorganization Reviewed

    Sayaka Kazami, Masak Takaine, Hiroyasu Itoh, Takaaki Kubota, Jun'ichi Kobayashi, Takeo Usui

    Biological and Pharmaceutical Bulletin   37 ( 12 )   1944 - 1947   2014.12

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    Iejimalides (IEJLs) A-D are 24-membered macrolides isolated from a tunicate Eudistoma cf. rigida, and exhibit potent cytotoxicity in vitro and antitumor activity in vivo. We previously reported that the molecular target of IEJL-A and -B was the vacuolar-type H+-ATPases (V-ATPases). However IEJL-C and -D, which are sulfonylated IEJL-A and -B, respectively, show more potent antitumor activity, and their molecular targets remain to be discovered. Here, we report that IEJL-C is also a potent V-ATPase inhibitor by binding in a site similar to the bafilomycin-binding site. Two-hour treatment with IEJL-C resulted in the complete disappearance of acidic organelles in HeLa cells. Interestingly, after 24-h treatment, small actin aggregates were observed instead of actin fibers. The same actin reorganization was also observed in cells treated with another V-ATPase inhibitor, bafilomycin A(1). Because IEJLs did not inhibit actin polymerization in vitro, these results suggest that the primary target of IEJL-C, as well as IEJL-A and -B, is V-ATPase, and actin reorganizations are probably caused by the disruption of pH homeostasis via V-ATPase inhibition.

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  • Amphidinins C-F, amphidinolide Q analogues from marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Takahiro Iwai, Kanae Sakai, Tohru Gonoi, Jun'ichi Kobayashi

    Organic Letters   16 ( 21 )   5624 - 5627   2014.11

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    Four new polyketides, amphidinins CF (14), have been isolated from the culture broth of symbiotic dinoflagellate Amphidinium sp. The analysis of their spectral data revealed that amphidinins CF (14) were 4,5-seco-analogues of amphidinolide Q (5). The absolute configurations of the new compounds were elucidated by the combination of J-based configuration analysis, modified Moshers method, and chemical derivatization. Amphidinins D (2) and F (4) are the first glycosides related to amphidinolides. Amphidinins CF (14) showed antimicrobial activity against bacteria and/or fungi.

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  • Absolute configuration of amphidinin A Reviewed

    Takahiro Iwai, Takaaki Kubota, Jun'Ichi Kobayashi

    Journal of Natural Products   77 ( 6 )   1541 - 1544   2014.6

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    The absolute configurations at six stereogenic centers in amphidinin A (1), a cytotoxic linear polyketide isolated from a symbiotic marine dinoflagellate, Amphidinium sp., were elucidated to be 2R, 4R, 6S, 9R 11R, and 12S by the combination of J-based configuration analysis, modified Mosher's method, and density-functional theory calculations.

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  • Nagelamide I and 2,2'-Didebromonagelamide B, new dimeric bromopyrrole-imidazole alkaloids from a marine sponge agelas sp Reviewed

    Takahiro Iwai, Takaaki Kubota, Jane Fromont, Junichi Kobayashi

    Chemical and Pharmaceutical Bulletin   62 ( 2 )   213 - 216   2014.2

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    New dimeric bromopyrrole-imidazole alkaloids, nagelamide I (1) and 2,2'-didebromonagelamide B (2), have been isolated from an Okinawan marine sponge Agelas species. The structures of 1 and 2 were elucidated based on analyses of the spectral data. Nagelamide I (1) was the first symmetric dimeric bromopyrrole-imidazole alkaloid consisting of two subunits connected with a single bond.

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  • Nakijiquinone S and nakijinol C, new meroterpenoids from a marine sponge of the family spongiidae Reviewed

    Haruna Suzuki, Takaaki Kubota, Azusa Takahashi-Nakaguchi, Jane Fromont, Tohru Gonoi, Junichi Kobayashi

    Chemical and Pharmaceutical Bulletin   62 ( 2 )   209 - 212   2014.2

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    New meroterpenoids, nakijiquinone S (1) and nakijinol C (2), have been isolated from an Okinawan marine sponge of the family Spongiidae. The gross structures and relative stereochemistries of 1 and 2 were elucidated on the basis of their spectral data. Nakijiquinone S (1) and nakijinol C (2) were new meroterpenoids consisting of a clerodane-type decalin ring connected to a 2-butoxy-5-hydroxy-benzoquinone unit or methyl 2,3,4-trihydroxybenzoate unit through a methylene, respectively. Nakijiquinone S (1) and nakijinol C (2) showed antimicrobial activities against several bacteria and fungi.

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  • Taurospongins B and C, new acetylenic fatty acid derivatives possessing a taurine amide residue from a marine sponge of the family Spongiidae Reviewed

    Takaaki Kubota, Haruna Suzuki, Azusa Takahashi-Nakaguchi, Jane Fromont, Tohru Gonoi, Jun'Ichi Kobayashi

    RSC Advances   4 ( 22 )   11073 - 11079   2014

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    Two new acetylenic fatty acid derivatives possessing a taurine amide residue, taurospongins B (1) and C (2), have been isolated from an Okinawan marine sponge of the family Spongiidae. The gross structures of 1 and 2 were elucidated on the basis of their spectral data, especially 2D NMR and FABMS/MS data. The absolute configurations for 1 and 2 were established by chemical means. Taurospongin C (2) showed inhibitory activity against Cryptococcus neoformans.

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  • Hyrtimomines D and E, bisindole alkaloids from a marine sponge Hyrtios sp. Reviewed

    Naonobu Tanaka, Rei Momose, Yohei Takahashi, Takaaki Kubota, Azusa Takahashi-Nakaguchi, Tohru Gonoi, Jane Fromont, Jun'Ichi Kobayashi

    Tetrahedron Letters   54 ( 31 )   4038 - 4040   2013.7

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    Two new alkaloids, hyrtimomines D (1) and E (2), were isolated from an Okinawan marine sponge Hyrtios sp. The structures of 1 and 2 were elucidated on the basis of spectroscopic analysis. Hyrtimomines D (1) and E (2) are structurally unique bisindole alkaloids possessing the canthin-6-one skeleton with a hydroxyindole and an imidazolium units. Hyrtimomines D (1) and E (2) exhibited antimicrobial activity. © 2013 Elsevier Ltd. All rights reserved.

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  • Revised structure and stereochemical assignments of amphidinolide N Reviewed

    Yohei Takahashi, Takaaki Kubota, Misako Imachi, Markus R. Wälchli, Jun'ichi Kobayashi

    Journal of Antibiotics   66 ( 5 )   277 - 279   2013.5

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  • Stereochemistry of theonezolides A-C Reviewed

    Kohei Nozawa, Masashi Tsuda, Naonobu Tanaka, Takaaki Kubota, Eri Fukushi, Jun Kawabata, Jun'Ichi Kobayashi

    Tetrahedron Letters   54 ( 8 )   783 - 787   2013.2

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    Theonezolides A-C (1-3) are cytotoxic 37-membered macrolides with a long side chain isolated from an Okinawan marine sponge Theonella sp. The relative stereochemistry of 1-3 was investigated by combination of NMR analysis including application of a JBCA method, a Universal NMR database, and a C-13-acetonide method. Furthermore, the absolute configurations at 14 chiral centers in 1-3 were found to be 19S, 22R, 24S, 28S, 44S, 45S, 47R, 49S, 53R, 55S, 57S, 59S, 60S, and 63S by application of a modified Mosher's method. (C) 2012 Elsevier Ltd. All rights reserved.

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  • Zamamiphidin A, a new manzamine related alkaloid from an Okinawan marine sponge amphimedon sp. Reviewed

    Takaaki Kubota, Yuki Kamijyo, Azusa Takahashi-Nakaguchi, Jane Fromont, Tohru Gonoi, Jun'Ichi Kobayashi

    Organic Letters   15 ( 3 )   610 - 612   2013.2

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    A manzamine related alkaloid, zamamiphidin A (1), consisting of a new heptacyclic ring system has been isolated from an Okinawan marine sponge Amphimedon sp. The structure of 1 including the relative stereochemistry was elucidated on the basis of the spectroscopic data. Compound 1 showed antibacterial activity against Staphylococcus aureus (MIC, 32 mu g/mL).

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  • Pyrinodemins G-I, new bis-3-alkylpyridine alkaloids from a marine sponge Amphimedon sp. Reviewed

    Takaaki Kubota, Ken'Ichi Kura, Jane Fromont, Jun'Ichi Kobayashi

    Tetrahedron   69 ( 1 )   96 - 100   2013.1

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    Three new bis-3-alkylpyridine alkaloids, pyrinodemins G-I (1-3), were isolated from an Okinawan marine sponge Amphimedon sp. and the structures of 1-3 were elucidated on the basis of spectroscopic data. Pyrinodemins G-I (1-3) were novel bis-3-alkylpyridine alkaloids possessing an N-methoxy amide moiety, an alpha,beta-unsaturated 3,5-disubstituted gamma-lactone moiety, and a 2,3-di-substituted acrolein at a junction of two 3-alkylpyridines, respectively. Pyrinodemins G (1) and H (2) showed cytotoxicity against P388 murine leukemia cells. (C) 2012 Elsevier Ltd. All rights reserved.

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  • Inhibitory effects of metachromins L-Q and its related analogs against receptor tyrosine kinases EGFR and HER2 Reviewed

    Yohei Takahashi, Takaaki Kubota, Sunao Yamamoto, Jun'Ichi Kobayashi

    Bioorganic and Medicinal Chemistry Letters   23 ( 1 )   117 - 118   2013.1

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    Metachromins are a series of sesquiterpenoid quinones isolated from Okinawan marine sponges. Inhibitory effects of metachromins L-Q (1-6), sesquiterpenoid quinones with an amino acid residue, and their related analogs (7-18) prepared from metachromins A (19) and C (20) against receptor tyrosine kinases EGFR and HER2 were investigated. Two analogs 11 and 12 showed relatively stronger inhibitory activity against EGFR, while metachromins L-Q (1-6) and seven analogs (8, 10, 11, and 15-18) showed inhibitory activities against HER2.

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  • Manzamenones L-N, new dimeric fatty-acid derivatives from an Okinawan marine sponge Plakortis sp. Reviewed

    Takaaki Kubota, Yuichiro Ishiguro, Azusa Takahashi-Nakaguchi, Jane Fromont, Tohru Gonoi, Jun'Ichi Kobayashi

    Bioorganic and Medicinal Chemistry Letters   23 ( 1 )   244 - 247   2013.1

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    Three new polyketides, manzamenones L-N (1-3), have been isolated from an Okinawan marine sponge of the genus Plakortis. The structures of 1-3 were elucidated on the basis of spectroscopic data. Manzamenones L-N (1-3) were new dimeric fatty-acid derivatives consisting of a tetrahydroindenone with three carboxy groups and two hexadecanyl chains. Manzamenones M (2) and N (3) showed antimicrobial activity against several bacteria and fungi. (c) 2012 Elsevier Ltd. All rights reserved.

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  • Tyrokeradines C-F, new bromotyrosine alkaloids from the Verongid sponges Reviewed

    Takaaki Kubota, Shinya Watase, Hiroya Mukai, Jane Fromont, Jun'ichi Kobayashi

    Chemical and Pharmaceutical Bulletin   60 ( 12 )   1599 - 1601   2012.12

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    Four new bromotyrosine alkaloids, tyrokeradines C-F (1-4), have been isolated from Okinawan marine sponges of the order Verongidae. The structures of 1-4 were elucidated on the basis of spectroscopic data. Tyrokeradines C (1) and D (2) are new bromotyrosine alkaloids possesing an imidazole ring, while tyrokeradines E (3) and F (4) are new bromotyrosine alkaloids possesing a cyano group.

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  • Agelasines O-U, new diterpene alkaloids with a 9-N-methyladenine unit from a marine sponge Agelas sp. Reviewed

    Takaaki Kubota, Takahiro Iwai, Azusa Takahashi-Nakaguchi, Jane Fromont, Tohru Gonoi, Jun'Ichi Kobayashi

    Tetrahedron   68 ( 47 )   9738 - 9744   2012.11

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    New diterpene alkaloids, agelasines O-U (1-7), have been isolated from an Okinawan marine sponge Agelas sp. The gloss structures and relative stereochemistries of 1-7 were elucidated from the spectroscopic data. Agelasines O-R (1-4) were the third examples of diterpene alkaloid with a 9-N-methyladenine and a pyrrole units. Agelasine O (1) has a halimane skeleton, while agelasines P-R (2-4) have a clerodane skeleton. Agelasines S-U (5-7) were new diterpene alkaloids with a 9-N-methyladenine unit consisting of a halimane skeleton, a labdane skeleton, and a clerodane skeleton, respectively. Agelasines O-R (1-4) and T (6) showed antimicrobial activities against several bacteria and fungi. (c) 2012 Elsevier Ltd. All rights reserved.

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  • Heteroaromatic alkaloids, nakijinamines, from a sponge Suberites sp. Reviewed

    Yohei Takahashi, Naonobu Tanaka, Takaaki Kubota, Haruaki Ishiyama, Azusa Shibazaki, Tohru Gonoi, Jane Fromont, Jun'Ichi Kobayashi

    Tetrahedron   68 ( 41 )   8545 - 8550   2012.10

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    The structures of seven new secondary metabolites isolated from an Okinawan marine sponge Suberites sp., nakijinamines A (1), B (2), and F-I (3-6) and 6-bromoconicamin (7), have been elucidated on the basis of spectroscopic analysis, chemical conversion, and conformational analysis. These analyses disclosed that 1-6 were heteroaromatic alkaloids having the hybrid structures of an aaptamine-type alkaloid and an indole alkaloid, while 7 was a bromoindole alkaloid. Nakijinamine I (6) is the first example of an aaptamine-type alkaloid possessing a 1,4-dioxane ring. Antimicrobial activities of 1-7 were evaluated. (C) 2012 Elsevier Ltd. All rights reserved.

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  • Halichonadins K and L, new dimeric sesquiterpenoids from a sponge Halichondria sp. Reviewed

    Naonobu Tanaka, Shohei Suto, Haruaki Ishiyama, Takaaki Kubota, Akihito Yamano, Motoo Shiro, Jane Fromont, Jun'Ichi Kobayashi

    Organic Letters   14 ( 13 )   3498 - 3501   2012.7

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    Two new structurally unique dimeric sesquiterpenoids, halichonadins K (1) and L (2), were isolated from an Okinawan marine sponge Halichondria sp. The structures of 1 and 2 were elucidated on the basis of spectroscopic analysis including a single crystal X-ray diffraction analysis and chemical conversion. Halichonadins K (1) and L (2) are homodimers of the eudesmane sesquiterpene linked with a piperidine ring through amide bonds. Halichonadin K (1) showed moderate cytotoxicity against KB cells.

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  • Eudistomidins H-K, new β-carboline alkaloids from the Okinawan marine tunicate Eudistoma glaucus Reviewed

    Teppei Suzuki, Takaaki Kubota, Jun'Ichi Kobayashi

    Bioorganic and Medicinal Chemistry Letters   21 ( 14 )   4220 - 4223   2011.7

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    Four new beta-carboline alkaloids, eudistomidins H-K (1-4), were isolated from an Okinawan marine tunicate Eudistoma glaucus and the structures of 1-4 were elucidated on the basis of spectroscopic data. Eudistomidins H (1) and I (2) were new beta-carboline alkaloids possessing a unique fused-tetracyclic ring system consisting of a tetrahydro beta-carboline ring and a hexahydropyrimidine ring. Eudistomidin J (3) showed relatively potent cytotoxicity against murine leukemia cells P388 and L1210, and human epidermoid carcinoma cells KB in vitro. (C) 2011 Elsevier Ltd. All rights reserved.

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  • Nakijinamines C-E, new heteroaromatic alkaloids from the sponge suberites species Reviewed

    Yohei Takahashi, Takaaki Kubota, Azusa Shibazaki, Tohru Gonoi, Jane Fromont, Jun'Ichi Kobayashi

    Organic Letters   13 ( 12 )   3016 - 3019   2011.6

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    Three new heteroaromatic alkaloids, nakijinamines C-E (1-3), which are a hybrid of the aaptamine-type and bromoindole alkaloids possessing a taurine- or histidine-derived residue, have been isolated from an Okinawan marine sponge Suberites species. The structures of 1-3 were elucidated on the basis of spectroscopic data and chemical conversions. Nakijinamines C (1) and E (3) are the first natural products possessing a 1H-oxazolo[4',5':4,5]benzo[1,2,3-de][1,6]naphthyridine ring system.

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  • Hyrtioseragamines A and B, new alkaloids from the sponge hyrtios species Reviewed International journal

    Yohei Takahashi, Yoshiro Iinuma, Takaaki Kubota, Masashi Tsuda, Mitsuhiro Sekiguchi, Yuzuru Mikami, Jane Fromont, Jun'Ichi Kobayashi

    Organic Letters   13 ( 4 )   628 - 631   2011.2

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    Two novel alkaloids with a furo[2,3-b]pyrazin-2(1H)-one moiety and a guanidino group, hyrtioseragamines A (1) and B (2), have been isolated from an Okinawan marine sponge Hyrtios species. The structures of 1 and 2 were elucidated on the basis of spectroscopic data and chemical conversions. Compounds 1 and 2 are the first natural products possessing a furo[2,3-b]pyrazine-related moiety.

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  • Lyconadins D and E, and complanadine E, new Lycopodium alkaloids from Lycopodium complanatum Reviewed

    Kan'Ichiro Ishiuchi, Takaaki Kubota, Haruaki Ishiyama, Shigeki Hayashi, Toshiro Shibata, Koichiro Mori, Yutaro Obara, Norimichi Nakahata, Jun'Ichi Kobayashi

    Bioorganic and Medicinal Chemistry   19 ( 2 )   749 - 753   2011.1

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    Three new Lycopodium alkaloids, lyconadins D (1) and E (2), and complanadine E (3), were isolated from the club moss Lycopodium complanatum. Lyconadin D (1) was the first example of fastigiatine-type alkaloid isolated from Lycopodium complanatum. The structures and relative stereochemistry of 1-3 were elucidated on the basis of spectroscopic data. Complanadine E (3) enhanced mRNA expression for NGF. (C) 2010 Elsevier Ltd. All rights reserved.

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  • Lyconadins C and F, new Lycopodium alkaloids from Lycopodium complanatum Reviewed

    Kan'ichiro Ishiuchi, Takaaki Kubota, Haruaki Ishiyama, Shigeki Hayashi, Toshiro Shibata, Jun'ichi Kobayashi

    Tetrahedron Letters   52 ( 2 )   289 - 292   2011.1

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    New Lycopodium alkaloids, lyconadins C (1) and F (2), were isolated from the club moss Lycopodium complanatum. Lyconadin C (1) is a new C(16)N(2)-type Lycopodium alkaloid possessing unique fused-tetracyclic ring system consisting of a cycloheptene ring fused to a decahydroquinoline and pyridone rings. Lyconadin F (2) possesses a primary amide moiety in its molecular, which is the first example of Lycopodium alkaloids. Biogenetically, lyconadins C (1) and F (2) might be related to lyconadins A (4) and B (5). The structures and relative stereochemistry of 1 and 2 were elucidated on the basis of spectroscopic data. The absolute stereochemistry of 2 was elucidated by chemical correlations with lyconadin B (5) through hemiaminal form of lyconadin F (3). (C) 2010 Elsevier Ltd. All rights reserved.

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  • Pyrinodemins e and F, new 3-alkylpyridine alkaloids from sponge Amphimedon sp. Reviewed

    Ken'Ichi Kura, Takaaki Kubota, Jane Fromont, Jun'Ichi Kobayashi

    Bioorganic and Medicinal Chemistry Letters   21 ( 1 )   267 - 270   2011.1

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    Two new 3-alkylpyridine alkaloids, pyrinodemins E(1) and F(2), were isolated from an Okinawan marine sponge Amphimedon sp. and the structures of 1 and 2 were elucidated on the basis of spectroscopic data. Pyrinodemins E(1) and F(2) were novel 3-alkylpyridine alkaloids possessing a 4-(methoxyamino)piperidinone moiety and an indol-3-glyoxylamide moiety, respectively. Pyrinodemin E (1) showed cytotoxicity against P388 and L1210 murine leukemia cells. (C) 2010 Elsevier Ltd. All rights reserved.

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  • Amphidinolide C3, a new cytotoxic 25-membered macrolide from marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Akiko Suzuki, Mika Yamada, Shigeyuki Baba, Jun'ichi Kobayashi

    Heterocycles   82 ( 1 )   333 - 338   2010.12

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    A new cytotoxic 25-membered macrolide, amphidinolide C3 (1), has been isolated from marine dinoflagellate Amphidinium sp. (Y-56 strain), and the structure of 1 was elucidated on the basis of spectroscopic data and chemical means.

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  • Untenolide A, a new polyketide from an Okinawan marine sponge Plakortis sp. Reviewed

    Yuichiro Ishiguro, Takaaki Kubota, Jane Fromont, Motoo Shiro, Jun'ichi Kobayashi

    Tetrahedron Letters   51 ( 31 )   4023 - 4026   2010.8

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    A new polyketide, untenolide A (1), has been isolated from an Okinawan marine sponge Plakortis species, and the structure was elucidated from spectroscopic data and X-ray analysis. Untenolide A (1) is a new polyketide possessing a fused-pentacyclic skeleton with two hexadecanyl chains. (C) 2010 Elsevier Ltd. All rights reserved.

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  • Ceratinadins A-C, new bromotyrosine alkaloids from an Okinawan marine sponge Pseudoceratina sp. Reviewed

    Yuji Kon, Takaaki Kubota, Azusa Shibazaki, Tohru Gonoi, Jun'Ichi Kobayashi

    Bioorganic and Medicinal Chemistry Letters   20 ( 15 )   4569 - 4572   2010.8

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    Three new bromotyrosine alkaloids, ceratinadins A-C (1-3), were isolated from an Okinawan marine sponge Pseudoceratina sp. and the structures of 1-3 were elucidated on the basis of spectroscopic data. Ceratinadin A (1) was a novel bromotyrosine alkaloid possessing an N-imidazolyl-quinolinone moiety. Ceratinadins A (1) and B (2) showed antifungal activity. (C) 2010 Elsevier Ltd. All rights reserved.

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  • Eudistomidin G, a new β-carboline alkaloid from the Okinawan marine tunicate Eudistoma glaucus and structure revision of eudistomidin B Reviewed

    Yohei Takahashi, Haruaki Ishiyama, Takaaki Kubota, Jun'ichi Kobayashi

    Bioorganic and Medicinal Chemistry Letters   20 ( 14 )   4100 - 4103   2010.7

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    A new beta-carboline alkaloid, eudistomidin G (1), has been isolated from the Okinawan marine tunicate Eudistoma glaucus, and the structure was elucidated from spectroscopic data. Furthermore, the structure of eudistomidin B (2), which has been isolated from the same tunicate, was revised from 2a to 2b by detailed analyses of spectroscopic data. Asymmetric synthesis of the revised structure (2b) of eudistomidin B (2) and its (1S, 10S)-diastereomer (2c) has been accomplished with the Noyori catalytic asymmetric hydrogen-transfer reaction. The absolute configuration of eudistomidin B (2) was confirmed to be 2b possessing (1R, 10S)-configuration, from comparison of the (1)H NMR data, CD spectra, [a] D values, and HPLC analysis of 2b, 2c, and natural eudistomidin B. (C) 2010 Elsevier Ltd. All rights reserved.

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  • Nakijiquinones J-R, sesquiterpenoid quinones with an amine residue from okinawan marine sponges Reviewed

    Yohei Takahasbi, Masahiro Ushio, Takaaki Kubota, Sunao Yamamoto, Jane Fromont, Ju N.Ichi Kobayashi

    Journal of Natural Products   73 ( 3 )   467 - 471   2010.3

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    Nine new sesquiterpenoid quinones, nakijiquinones J-R (1 -9), have been isolated from three collections of Okinawan marine sponges of the family Spongiidae, and the structures and configurations were elucidated from the spectroscopic data and chemical correlations. Nakijiquinones J-L (1-3), M and N (4 and 5, respectively), 0 (6), 11 and Q (7 and 8, respectively), and R (9) are new sesquiterpenoid quinones possessing (S)-2-methylbutylamine, isopentylamine, isobutylamine, phenethylamine, and taurine residues, respectively, attached to each quinone ring.

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  • Platisidines A-C, N-methylpyridinium alkaloids from an okinawan marine sponge of Plakortis species Reviewed

    Takaaki Kubota, Yuichiro Ishiguro, Sunao Yamamoto, Jane Fromont, Jun'Ichi Kobayashi

    Heterocycles   80 ( 2 )   1407 - 1412   2010.3

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    Three new N-methyl pyridinium alkaloids, platisidines A-C (1-3), were isolated from an Okinawan marine sponge of the genus Plakortis, and the structures were elucidated from spectroscopic data. The structures of platisidines A-C (1-3) were elucidated to be N-methyl nicotinic acid derivatives with a n-hexadecanoyl chain. Platisidines A-C (1-3) showed inhibitory activity against acetylcholinesterase.

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  • Bioactive metabolites from marine dinoflagellates Reviewed

    Jun'ichi Kobayashi, Takaaki Kubota

    Comprehensive Natural Products II: Chemistry and Biology   2   263 - 325   2010.3

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  • Biyouxanthones A - D, prenylated xanthones from roots of Hypericum chinense Reviewed

    Naonobu Tanaka, Takuji Mamemura, Shuhei Abe, Kiyoshi Imabayashi, Yoshiki Kashiwada, Yoshihisa Takaishi, Tetsuro Suzuki, Yutaka Takebe, Takaaki Kubota, Jun'ichi Kobayashi

    Heterocycles   80 ( 1 )   613 - 621   2010.1

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    Four new prenylated xanthones, biyouxanthones A - D (1 - 4), were isolated from roots of Hypericum chinense. The gross structures of 1 - 4 were elucidated from spectroscopic data, and 2 was assigned as a racemate by chiral HPLC analysis. Biyouxanthones A (1) and B (2) exhibited anti-viral activity against hepatitis C virus (HCV).

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  • Benzosceptrin C, a new dimeric bromopyrrole alkaloid from sponge Agelas sp. Reviewed

    Takaaki Kubota, Atsushi Araki, Tetsuro Yasuda, Masashi Tsuda, Jane Fromont, Kazuki Aoyama, Yuzuru Mikami, Markus R. Wälchli, Jun'ichi Kobayashi

    Tetrahedron Letters   50 ( 52 )   7268 - 7270   2009.12

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    A new dimeric bromopyrrole alkaloid possessing a benzocyclobutane ring, benzosceptrin C (1), has been isolated from an Okinawan marine sponge of the genus Agelas (SS-956), and the structure and relative stereochemistry were elucidated from spectroscopic data. Benzosceptrin C (1) showed antimicrobial activity. (C) 2009 Elsevier Ltd. All rights reserved.

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  • Lycopladine H, a novel alkaloid with fused-tetracyclic skeleton from Lycopodium complanatum Reviewed

    Kan'Ichiro Ishiuchi, Takaaki Kubota, Shigeki Hayashi, Toshiro Shibata, Jun'Ichi Kobayashi

    Tetrahedron Letters   50 ( 47 )   6534 - 6536   2009.11

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    A novel Lycopodium alkaloid, lycopladine H (1), with a fused-tetracyclic ring system consisting of an azocane ring connected to a [2.2.2]-bicyclooctane ring and a 3-piperidone ring, was isolated from the club moss lycopodium complanatum. The structure and relative stereochemistry of I were elucidated on the basis of spectroscopic data (C) 2009 Elsevier Ltd All rights reserved

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  • Petiolins F-I, Benzophenone Rhamnosides from Hypericum pseudopetiolatum var. kiusianum

    Naonobu Tanaka, Takaaki Kubota, Yoshiki Kashiwada, Yoshihisa Takaishi, Jun'ichi Kobayashi

    CHEMICAL & PHARMACEUTICAL BULLETIN   57 ( 10 )   1171 - 1173   2009.10

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    Four new benzophenone-O-rhamnosides, petiolins F-I (1-4), were isolated from aerial parts of Hypericum pseudopetiolatum var. kiusianum, and the structures were elucidated by spectroscopic data and chemical means.

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  • Petiolins F-I, benzophenone rhamnosides from Hypericum pseudopetiolatum var. kiusianum Reviewed

    Naonobu Tanaka, Takaaki Kubota, Yoshiki Kashiwada, Yoshihisa Takaishi, Jun'ichi Kobayashi

    Chemical and Pharmaceutical Bulletin   57 ( 10 )   1171 - 1173   2009.10

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    Four new benzophenone-O-rhamnosides, petiolins F-I (1-4), were isolated from aerial parts of Hypericum pseudopetiolatum var. kiusianum, and the structures were elucidated by spectroscopic data and chemical means.

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  • Yezo'otogirins A-C, new tricyclic terpenoids from Hypericum yezoense Reviewed

    Naonobu Tanaka, Yuka Kakuguchi, Haruaki Ishiyama, Takaaki Kubota, Jun'ichi Kobayashi

    Tetrahedron Letters   50 ( 33 )   4747 - 4750   2009.8

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    Three new tricyclic terpenoids, yezo'otogirins A-C (1-3), were isolated from aerial parts of Hypericum yezoense. The structures including absolute stereochemistry of 1-3 were elucidated from the spectroscopic data and conformational analysis. (C) 2009 Elsevier Ltd. All rights reserved.

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  • Lannotinidines H-J, new Lycopodium alkaloids from Lycopodium annotinum

    Kan'ichiro Ishiuchi, Shihomi Kodama, Takaaki Kubota, Shigeki Hayashi, Toshiro Shibata, Jun'ichi Kobayashi

    Chemical and Pharmaceutical Bulletin   57 ( 8 )   877 - 881   2009.8

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    Three new Lycopodium alkaloids, lannotinidines H-J (1-3), were isolated from the club moss Lycopodium annotinum. The structures and relative stereochemistry of 1-3 were elucidated on the basis of spectroscopic data and the absolute stereochemistry of 2 was assigned by chemical correlation. Lannotinidine H (1) is the first Lycopodium alkaloid possessing a lycopodane skeleton with an additional C-3 unit.

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  • Lannotinidines H-J, New Lycopodium Alkaloids from Lycopodium annotinum Reviewed

    Kan'ichiro Ishiuchi, Shihomi Kodama, Takaaki Kubota, Shigeki Hayashi, Toshiro Shibata, Jun'ichi Kobayashi

    CHEMICAL & PHARMACEUTICAL BULLETIN   57 ( 8 )   877 - 881   2009.8

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    Three new Lycopodium alkaloids, lannotinidines H-J (1-3), were isolated from the club moss Lycopodium annotinum. The structures and relative stereochemistry of 1-3 were elucidated on the basis of spectroscopic data and the absolute stereochemistry of 2 was assigned by chemical correlation. Lannotinidine H (1) is the first Lycopodium alkaloid possessing a lycopodane skeleton with an additional C-3 unit.

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  • Lycopladines F and G, new C<inf>16</inf>N<inf>2</inf>-type alkaloids with an additional C<inf>4</inf>N unit from Lycopodium complanatum Reviewed

    Kan'ichiro Ishiuchi, Takaaki Kubota, Shigeki Hayashi, Toshiro Shibata, Jun'ichi Kobayashi

    Tetrahedron Letters   50 ( 29 )   4221 - 4224   2009.7

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    Two new Lycopodium alkaloids, lycopladines F (1) and G (2), have been isolated from the club moss Lycopodium complanatum, and the structures and relative stereochemistries of I and 2 were elucidated on the basis of spectroscopic data. Lycopladine F (1) is a rare C16N2-type Lycopodium alkaloid possessing an amino acid residue (C4N) (C) 2009 Elsevier Ltd. All rights reserved.

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  • Plakoridine C, a novel piperidine alkaloid from an Okinawan marine sponge Plakortis sp. Reviewed

    Yuichiro Ishiguro, Takaaki Kubota, Kan'ichiro Ishiuchi, Jane Fromont, Jun'ichi Kobayashi

    Tetrahedron Letters   50 ( 26 )   3202 - 3204   2009.7

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    A new piperidine alkaloid plakoridine C (1) has been isolated from an Okinawan marine sponge Plakortis species, and the structure was elucidated from spectroscopic data. Plakoridine C (1) is a new alkaloid possessing a piperidine ring connected to a beta-keto-gamma-lactone through a double bond. (C) 2009 Elsevier Ltd. All rights reserved.

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  • Serratezomines D and E, new Lycopodium alkaloids from Lycopodium serratum var. serratum Reviewed

    Takaaki Kubota, Hiroko Yahata, Sunao Yamamoto, Shigeki Hayashi, Toshiro Shibata, Jun'ichi Kobayashi

    Bioorganic and Medicinal Chemistry Letters   19 ( 13 )   3577 - 3580   2009.7

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    Two new Lycopodium alkaloids, serratezomines D (1) and E (2), were isolated from the club moss Lycopodium serratum var. serratum. Serratezomine D (1) is a new lucidine-type alkaloid, while serratezomine E (2) is a new phlegmarane-type alkaloid. The structures and relative stereochemistry of 1 and 2 were elucidated on the basis of spectroscopic data. Serratezomine D (1) exhibited an inhibitory activity against acetylcholinesterase. (C) 2009 Elsevier Ltd. All rights reserved.

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  • The Daphniphyllum alkaloids Reviewed

    Jun'Ichi Kobayashi, Takaaki Kubota

    Natural Product Reports   26 ( 7 )   936 - 962   2009.7

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    About two hundred Daphniphyllum alkaloids have so far been isolated from thirteen species of the genus Daphniphyllum. This comprehensive review summarizes all the research into the isolation and structure elucidation of these alkaloids reported since investigations began in 1966. The structures of the Daphniphyllum alkaloids are classified based on six Daphniphyllum alkaloids (daphniphylline, secodaphniphylline, yuzurimine, daphnilactone A, daphnilactone B and yuzurine); there are also a number of newly found skeletons. The biosynthetic pathways, total syntheses, and bioactivities of the Daphniphyllum alkaloids are also described.

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  • Daphnezomines T-V, Alkaloids from Daphniphyllum humile Reviewed

    Takaaki Kubota, Teppei Suzuki, Kan'ichiro Ishiuchi, Taiga Kuhara, Jun'ichi Kobayashi

    CHEMICAL & PHARMACEUTICAL BULLETIN   57 ( 5 )   504 - 507   2009.5

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    Three new Daphniphyllum alkaloids, daphnezomines T-V (1-3), were isolated from the leaves and branches of Daphniphyllum humile (Daphniphyllaceae). The structures and relative stereochemistry of 1-3 were elucidated on the basis of spectroscopic data. Daphnezomine T (1) is the first alkaloid without a branched C-1 unit at C-5 among all Daphiniphyllum alkaloids reported so far.

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  • Daphnezomines T-V, alkaloids from Daphniphyllum humile

    Takaaki Kubota, Teppei Suzuki, Kan'ichiro Ishiuchi, Taiga Kuhara, Jun'ichi Kobayashi

    Chemical and Pharmaceutical Bulletin   57 ( 5 )   504 - 507   2009.5

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    Three new Daphniphyllum alkaloids, daphnezomines T-V (1-3), were isolated from the leaves and branches of Daphniphyllum humile (Daphniphyllaceae). The structures and relative stereochemistry of 1-3 were elucidated on the basis of spectroscopic data. Daphnezomine T (1) is the first alkaloid without a branched C-1 unit at C-5 among all Daphiniphyllum alkaloids reported so far.

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  • Total synthesis of amphidinolactone A and its absolute configuration Reviewed

    Masahiro Hangyou, Haruaki Ishiyama, Yohei Takahashi, Takaaki Kubota, Jun'ichi Kobayashi

    Tetrahedron Letters   50 ( 13 )   1475 - 1477   2009.4

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    Asymmetric synthesis of amphidinolactone A, a cytotoxic macrolide from the Cultured dinoflagellate Amphidinium sp., has been accomplished. Absolute configuration of amphidinolactone A was concluded to be 1 from comparison of the NMR data and vertical bar x vertical bar(D) values of synthetic and natural amphidinolactone A. (C) 2009 Elsevier Ltd. All rights reserved.

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  • Total synthesis and biological evaluation of amphidinolide v and analogues Reviewed

    Alois Fürstner, Susanne Flügge, Oleg Larionov, Yohei Takahashi, Takaaki Kubota, Juńichi Kobayashi

    Chemistry - A European Journal   15 ( 16 )   4011 - 4029   2009.4

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    A sequence of ring-closing alkyne metathesis followed by an intermolecular enyne metathesis of the resulting cycloalkyne with ethene was used to forge the macrocyclic skeleton and to set the vicinal exo-methylene branches characteristic for the cytotoxic marine natural product amphidinolide V (1). Comparison of the synthetic material with all authentic sample of this extremely scarce metabolite isolated from a dinoflagellate of the Amphidinium sp. eliminated any, doubts about its structure and allowed the absolute configuration of amphidinolide V to be determined as 8R,9S,10S,13R. Moreover, the flexibility inherent to the underlying Synthesis blueprint also opened access to a comprehensive set of diastereomers of I as well as to synthetic analogues differing from the natural lead in the lipophilic chains appended to the macrocyclic core. This set of designed analogues gave first insights into structure-activity relationships, which revealed that the stereo-structure Of the macrolactone is a highly critical parameter, whereas the examined alterations of the side chain did not diminish the cytotoxicity, of the compounds to any notable extent.

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  • Petiolins D and E, phloroglucinol derivatives from Hypericum pseudopetiolatum var. kiusianum Reviewed

    Naonobu Tanaka, Takaaki Kubota, Haruaki Ishiyama, Yoshiki Kashiwada, Yoshihisa Takaishi, Junji Ito, Yuzuru Mikami, Motoo Shiro, Jun'ichi Kobayashi

    Heterocycles   79 ( C )   917 - 924   2009.4

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    A new phloroglucinol derivative possessing citran skeleton, petiolin D (1), and a new chromone glucoside, petiolin E (2), were isolated from aerial parts of Hypericum pseudopetiolatum var. kiusianum. The structures of I and 2 were elucidated by spectroscopic data, and a single-crystal X-ray diffraction analysis of 1 revealed that 1 was a racemic mixture.

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  • Nagelamides Q and R, novel dimeric bromopyrrole alkaloids from sponges agelas sp Reviewed

    Atsushi Araki, Takaaki Kubota, Kazuki Aoyama, Yuzuru Mikami, Jane Fromont, Ju N.Ichi Kobayashi

    Organic Letters   11 ( 8 )   1785 - 1788   2009.4

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    Two new dimeric bromopyrrole alkaloids, nagelamides Q (1) and R (2), have been isolated from Okinawan marine sponges of the genus Agelas (SS-1134 and SS-956, respectively), and the structures and stereochemistry were elucidated from spectroscopic data. Nagelamide Q (1) is a rare dimeric bromopyrrole alkaloid possessing a pyrrolidine ring, while nagelamide R (2) is the first bromopyrrole alkaloid having an oxazoline ring. Nagelamides Q (1) and R (2) showed antimicrobial activity.

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  • Naucleamide F, a new monoterpene indole alkaloid from Nauclea Latifolia Reviewed

    Yuka Kakuguchi, Haruaki Ishiyama, Takaaki Kubota, Jun'ichi Kobayashi

    Heterocycles   79 ( C )   765 - 771   2009.4

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    A new monoterpene indole alkaloid, naucleamide F (1), has been isolated from the bark and wood of Nauclea latifolia, and the structure and stereochemistry were elucidated on the basis of the spectral data. Naucleamide F (1) is a new monoterpene indole alkaloid consisting of a tetrahydro-beta-carboline ring fused to a pyridone ring, and a 1,3,5-trioxepane ring fused to a dihydropyran ring and a glucose unit.

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  • Bromopyrrole alkaloids from marine sponges of the genus agelas Reviewed

    Tetsuro Yasuda, Atsushi Araki, Takaaki Kubota, Junji Ito, Yuzuru Mikami, Jane Fromont, Ju N.Ichi Kobayashi

    Journal of Natural Products   72 ( 3 )   488 - 491   2009.3

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    Four new bromopyrrole alkaloids, nagelamides O (1) and P (2) and mukanadins E (3) and F (4), were isolated from three collections of Okinawan marine sponges of the genus Agelas. The structures and sterectchemistry of 1-4 were elucidated on the basis of their spectroscopic data.

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  • Nakijiquinones E and F, new dimeric sesquiterpenoid quinones from marine sponge Reviewed

    Yohei Takahashi, Takaaki Kubota, Jun'ichi Kobayashi

    Bioorganic and Medicinal Chemistry   17 ( 6 )   2185 - 2188   2009.3

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    Two new dimeric sesquiterpenoid quinones, nakijiquinones E (1) and F (2), have been isolated from an Okinawan marine sponge, and the structures and relative stereochemistry of 1 and 2 were elucidated on the basis of the spectral data. Nakijiquinones E (1) and F (2) were the first dimeric sesquiterpenoid quinones possessing a 3-aminobenzoate moiety. (C) 2008 Elsevier Ltd. All rights reserved.

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  • Zamamidine C, 3,4-dihydro-6-hydroxy-10,11-epoxymanzamine A, and 3,4-dihydromanzamine J N-oxide, new manzamine alkaloids from sponge Amphimedon sp. Reviewed

    Mika Yamada, Yohei Takahashi, Takaaki Kubota, Jane Fromont, Aki Ishiyama, Kazuhiko Otoguro, Haruki Yamada, Satoshi Omura, Jun'ichi Kobayashi

    Tetrahedron   65 ( 11 )   2313 - 2317   2009.3

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    New manzamine alkaloids, zamamidine C (1), 3,4-dihydro-6-hydroxy-10,11-epoxymanzamine A (2), and 3,4-dihydromanzamine J N-oxide (3). have been isolated from an Okinawan marine sponge Amphimedon species. The Structures and stereochemistries of 1-3 were elucidated from the spectroscopic data and chemical derivatization. Zamamidine C (1) is a new manzamine alkaloid possessing a second beta-carboline ring via an ethylene unit at N-2 of manzamine D, while 3,4-dihydro-6-hydroxy-10,11-epoxymanzamine A (2) is the first manzamine alkaloid possessing an epoxide ring at C-10 and C-11. Zamamidine C (1) showed significant antitrypanosomal activity against Trypanosoma brucei brucei, the parasite associated with sleeping sickness, and antimalarial activity against Plasmodium falciparum, the causative agent of malaria in vitro. (C) 2009 Elsevier Ltd. All rights reserved.

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  • Tyrokeradines A and B, new bromotyrosine alkaloids with an imidazolyl-quinolinone moiety from a Verongid sponge Reviewed

    Hiroya Mukai, Takaaki Kubota, Kazuki Aoyama, Yuzuru Mikami, Jane Fromont, Jun'ichi Kobayashi

    Bioorganic and Medicinal Chemistry Letters   19 ( 5 )   1337 - 1339   2009.3

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    Two new bromotyrosine alkaloids, tyrokeradines A (1) and B (2), with an imidazolyl-quinolinone moiety have been isolated from an Okinawan marine sponge of the order Verongida. The structures of 1 and 2 were elucidated on the basis of spectroscopic data. (C) 2009 Elsevier Ltd. All rights reserved.

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  • Zamamidines A and B, new manzamine alkaloids from the sponge Amphimedon species Reviewed

    Yohei Takahashi, Takaaki Kubota, Jane Fromont, Jun'ichi Kobayashi

    Organic Letters   11 ( 1 )   21 - 24   2009.1

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    New manzamine alkaloids, zemamidines A (1) and B (2), have been isolated from an Okinawan marine sponge Amphimedon species. The structures and stereochemistry of 1 and 2 were elucidated from the spectroscopic data and conformational analysis. Zamamidines A (1) and B (2) are the first manzamine alkaloids possessing a second beta-carboline ring via an ethylene unit at N-2 of manzamine H and 1,2,3,4-tetrahydromanzamine B, respectively.

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  • Calyciphyllines N-P, alkaloids from Daphniphyllum calycinum Reviewed

    Hiroko Yahata, Takaaki Kubota, Jun'ichi Kobayashi

    Journal of Natural Products   72 ( 1 )   148 - 151   2009.1

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    Three new Daphniphyllum alkaloids, calyciphyllines N-P (1-3), were isolated from the leaves and stems of Daphniphyllum calycinum. The structures and relative stereochemistry of 1-3 were elucidated on the basis of spectroscopic data.

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  • Nagelamides M and N, new bromopyrrole alkaloids from sponge Agelas species Reviewed

    Takaaki Kubota, Atsushi Araki, Junji Ito, Yuzuru Mikami, Jane Fromont, Jun'ichi Kobayashi

    Tetrahedron   64 ( 48 )   10810 - 10813   2008.11

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    Two new bromopyrrole alkaloids, nagelamides M (1) and N (2), have been isolated from an Okinawan marine sponge Agelas species, and the structures and stereochemistry were elucidated from the spectroscopic data. Nagelamide M (1) is a novel bromopyrrole alkaloid possessing a 2-amino-octahydropyrrolo[2,3-d]imidazole ring with a taurine unit, while nagelamide N (2) is a new bromopyrrole alkaloid possessing a 2-amino-tetrahydroimidazole-4-one ring with a taurine unit and 3-(dibromopyrrole-2-carboxamido)propanoic acid moiety. Nagelamides M (1) and N (2) exhibited antimicrobial activity. (C) 2008 Elsevier Ltd. All rights reserved.

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  • Xestosaprol C, a new pentacyclic hyroquinone sulfate from a marine sponge xestospongia sapra Reviewed

    Takaaki Kubota, Yuji Kon, Jun'ichi Kobayashi

    Heterocycles   76 ( 2 )   1571 - 1575   2008.11

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    A new pentacyclic hydroquinone sulfate with a 2,5-dihydro-2,5-furandiol ring, xestosaprol C (1), has been isolated from an Okinawan marine sponge Xestospongia sapra. The structure of I was elucidated by the spectroscopic data.

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  • Absolute stereochemistry of amphidinolide Q Reviewed

    Yohei Takahashi, Takaaki Kubota, Eri Fukushi, Jun Kawabata, Jun'ichi Kobayashi

    Organic Letters   10 ( 17 )   3709 - 3711   2008.9

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    The absolute configurations at five chiral centers in amphidinolide Q (1), a cytotoxic 12-membered macrolide isolated from a marine dinoflagellate Amphidinium sp., were elucidated to be 4R, 7R, 9S, 11 R, and 13R on the basis of NMR analyses and a modified Mosher&apos;s method.

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  • Nakijiquinones G-I, new sesquiterpenoid quinones from marine sponge Reviewed

    Yohei Takahashi, Takaaki Kubota, Junji Ito, Yuzuru Mikami, Jane Fromont, Jun'ichi Kobayashi

    Bioorganic and Medicinal Chemistry   16 ( 16 )   7561 - 7564   2008.8

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    Three new sesquiterpenoid quinones, nakijiquinones G-I (1-3), containing a different amino group derived from amino acids have been isolated from Okinawan marine sponges of the family Spongiidae, and the structures and relative stereochemistry of 1-3 were elucidated on the basis of the spectral data. Nakijiquinones G-I (1-3) showed modest cytotoxicity and inhibitory activity against HER2 kinase, while nakijiquinone H (2) exhibited antimicrobial activity. (C) 2008 Elsevier Ltd. All rights reserved.

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  • Nagelamides K and L, dimeric bromopyrrole alkaloids from sponge Agelas species Reviewed

    Atsushi Araki, Takaaki Kubota, Masashi Tsuda, Yuzuru Mikami, Jane Fromont, Jun'ichi Kobayashi

    Organic Letters   10 ( 11 )   2099 - 2102   2008.6

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    Two new dimeric bromopyrrole alkaloids, nagelamides K (1) and L (2), have been isolated from Okinawan marine sponges Agelas species, and the structures and stereochemistry were elucidated from spectroscopic data. Nagelamide K (1) is a bromopyrrole alkaloid possessing a rare piperidinoiminoimidazolone ring with an aminoimidazole ring and a taurine unit, while nagelamide L (2) is a unique dimeric bromopyrrole alkaloid containing an ester linkage. Nagelamides K (1) and L (2) exhibited antimicrobial activity.

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  • Petiolins A-C, phloroglucinol derivatives from Hypericum pseudopetiolatum var. kiusianum Reviewed

    Naonobu Tanaka, Takaaki Kubota, Haruaki Ishiyama, Atsushi Araki, Yoshiki Kashiwada, Yoshihisa Takaishi, Yuzuru Mikami, Jun'ichi Kobayashi

    Bioorganic and Medicinal Chemistry   16 ( 10 )   5619 - 5623   2008.5

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    Two new phloroglucinol derivatives possessing chromane skeleton, petiolins A ( 1) and B ( 2), and a new phloroglucinol derivative containing a dihydrofuran ring, petiolin C ( 3), were isolated from aerial parts of Hypericum pseudopetiolatum var. kiusianum. The gross structures of 1-3 were elucidated by spectroscopic data, and the relative stereochemistry of 3 was elucidated by NOESY data. Petiolins A-C (1-3) showed modest cytotoxicity, while petiolin C ( 3) exhibited antifungal activity. (C) 2008 Elsevier Ltd. All rights reserved.

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  • Nakinadines B-F: new pyridine alkaloids with a β-amino acid moiety from sponge Amphimedon sp. Reviewed

    Takami Nishi, Takaaki Kubota, Jane Fromont, Takuma Sasaki, Jun'ichi Kobayashi

    Tetrahedron   64 ( 14 )   3127 - 3132   2008.3

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    Five new 3-alkylpyridine alkaloids with a P-amino acid moiety, nakinadines B-F (1-5), have been isolated from an Okinawan marine sponge Amphimedon sp. (SS-1059), and the structures and stereochemistry were elucidated by spectroscopic data. Nakinadines B (1) and C (2) showed modest cytotoxicity. (c) 2008 Elsevier Ltd. All rights reserved.

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  • Calyciphyllines H-M, new Daphniphyllum alkaloids from Daphniphyllum calycinum Reviewed

    Shizuka Saito, Hiroko Yahata, Takaaki Kubota, Yutaro Obara, Norimichi Nakahata, Jun'ichi Kobayashi

    Tetrahedron   64 ( 8 )   1901 - 1908   2008.2

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    Six new Daphniphyllum alkaloids, calyciphyllines H-M (1-6), were isolated from the leaves and stems of Daphniphyllum calycinum (Daphniphyllaceac). The structures and relative stereochemistry of 1-6 were elucidated on the basis of spectroscopic data, and the absolute stereochemistry of 3 was assigned by PGME method. (C) 2007 Elsevier Ltd. All rights reserved.

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  • Seragadine A, A β-carboline alkaloid from marine sponge Reviewed

    Kohei Nozawa, Masashi Tsuda, Takaaki Kubota, Jane Fromont, Jun'ichi Kobayashia

    Heterocycles   74 ( C )   849 - 853   2007.12

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    A new quaternary beta-carboline alkaloid, seragadine A (1), and three known related alkaloids (2 similar to 4) have been isolated from an Okinawan Haplosclerida sponge (SS-1022). The structure of 1 was determined by the spectroscopic data and its synthesis.

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  • Lycopladine E, a new C<inf>16</inf>N<inf>1</inf>-type alkaloid from lycopodium complanatum Reviewed

    Takaaki Kubota, Hiroko Yahata, Kan'ichiro Ishiuchi, Yutaro Obara, Norimichi Nakahat, Jun'ichi Kobayashi

    Heterocycles   74 ( C )   843 - 848   2007.12

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    A new C(16)N(1)-type alkaloid, lycopladine E (1), has been isolated from the club moss Lycopodium complanatum, and the structure and absolute stereochemistry were elucidated on the basis of spectroscopic data and chemical correlation.

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  • Nitrogen-containing verticillene diterpenoids from the Taiwanese soft coral Cespitularia taeniata Reviewed

    Ya Ching Shen, Yuan Bin Cheng, Jun'ichi Kobayashi, Takaaki Kubota, Yohei Takahashi, Yuzuru Mikami, Junji Ito, Yun Sheng Lin

    Journal of Natural Products   70 ( 12 )   1961 - 1965   2007.12

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    Extensive column chromatography of the ethanolic extract of the soft coral Cespitularia taeniata collected in Taiwan has resulted in the isolation of eight new nitrogen-containing verticillene diterpenes, designated cespitulactams D-K (1-8), together with three known diterpenes, cespitulactams A (9) and B (10) and cespitularin F. In addition, one new derivative, 6-O-acetyleespitulactam F (11), was prepared from compound 3. The structures of these compounds were elucidated on the basis of spectroscopic analyses, especially HRMS and 2D NMR experiments. The cytotoxicity against human oral epidermoid carcinoma (KB) and murine L1210 leukemia cell lines and antimicrobial activities of 1-8 and 11 were tested and evaluated. A biogenetic pathway for these novel diterpene alkaloids was also proposed.

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  • Metachromins R-T, new sesquiterpenoids from marine sponge Spongia sp. Reviewed

    Yohei Takahashi, Mika Yamada, Takaaki Kubota, Jane Fromont, Jun'ichi Kobayashi

    Chemical and Pharmaceutical Bulletin   55 ( 12 )   1731 - 1733   2007.12

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    Three new sesquiterpenoids, metachromins R-T (1-3), have been isolated from an Okinawan marine sponge Spongia sp. The structures and stereochemistry of 1-3 were elucidated on the basis of the spectroscopic data. Metachromins S (2) and T (3) showed modest cytotoxicity.

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  • Sarusubine A, a new dimeric Lythraceae alkaloid from Lagerstroemia subcostata Reviewed

    Kozue Watanabe, Takaaki Kubota, Takakazu Shinzato, Junji Ito, Yuzuru Mikami, Jun'ichi Kobayashi

    Tetrahedron Letters   48 ( 42 )   7502 - 7504   2007.10

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    A new dimeric Lythraceac alkaloid with a cyclobutane ring, sarusubine A (1), has been isolated from the leaves of Lagerstroemia subcostata, and the structure and stereochemistry were elucidated by spectroscopic data. (C) 2007 Elsevier Ltd. All rights reserved.

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  • Metachromins L-Q, new sesquiterpenoid quinones with an amino acid residue from sponge Spongia sp. Reviewed

    Yohei Takahashi, Takaaki Kubota, Jane Fromont, Jun'ichi Kobayashi

    Tetrahedron   63 ( 36 )   8770 - 8773   2007.9

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    Six new sesquiterpenoid quinones with an amino acid residue, metachromins L-Q (1-6), have been isolated from an Okinawan marine sponge Spongia sp. The structures and stereochemistry of 1-6 were elucidated on the basis of the spectroscopic data and chemical correlations. Metachromins L (1) and M (2) showed modest cytotoxicity. (c) 2007 Elsevier Ltd. All rights reserved.

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  • Calyciphylline G, a novel alkaloid with an unprecedented fused-hexacyclic skeleton from Daphniphyllum calycinum Reviewed

    Shizuka Saito, Takaaki Kubota, Jun'ichi Kobayashi

    Tetrahedron Letters   48 ( 32 )   5693 - 5695   2007.8

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    Calyciphylline G (1), a novel Daphniphyllum alkaloid with an unprecedented fused-hexacyclic skeleton containing a 5-azatricyclo[6.2.1.0(1,5)]undecane ring, has been isolated from the stem of Daphniphyllum calycinum (Daphniphyllaceae), and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data. (c) 2007 Elsevier Ltd. All rights reserved.

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  • Nakinadine A, a novel bis-pyridine alkaloid with a β-amino acid moiety from sponge Amphimedon sp. Reviewed

    Takaaki Kubota, Takami Nishi, Eri Fukushi, Jun Kawabata, Jane Fromont, Jun'ichi Kobayashi

    Tetrahedron Letters   48 ( 29 )   4983 - 4985   2007.7

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    A novel cytotoxic bis-3-alkylpyridine alkaloid with a beta-amino acid moiety, nakinadine A (1), has been isolated from an Okinawan marine sponge Amphimedon sp., and the structure and stereochemistry were elucidated by spectroscopic data. (C) 2007 Elsevier Ltd. All rights reserved.

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  • Nagelamide J, a novel dimeric bromopyrrole alkaloid from a sponge agelas species Reviewed

    Atsushi Araki, Masashi Tsuda, Takaaki Kubota, Yuzuru Mikami, Jane Fromont, Ju N.ichi Kobayashi

    Organic Letters   9 ( 12 )   2369 - 2371   2007.6

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    A novel dimeric bromopyrrole alkaloid, nagelamide J (1), with antimicrobial activity has been isolated from an Okinawan marine sponge Agelas species, and the structure and stereochemistry were elucidated from spectroscopic data. Nagelamide J (1) is the first bromopyrrole alkaloid possessing a cyclopentane ring fused to an amino imidazole ring.

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  • Amphidinolactone B, a new 26-membered macrolide from dinoflagellate Amphidinium sp. Reviewed

    Yohei Takahashi, Takaaki Kubota, Jun'ichi Kobayashi

    Journal of Antibiotics   60 ( 6 )   376 - 379   2007.6

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    A new 26-membered macrolide, amphidinolactone 13, has been isolated from a marine dinoflagellate Amphidinium sp., and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data. Amphidinolactone B (1) showed modest cytotoxicity.

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  • Calyciphyllines E and F, novel hepta- and pentacyclic alkaloids from Daphniphyllum calycinum Reviewed

    Shizuka Saito, Takaaki Kubota, Jun'ichi Kobayashi

    Tetrahedron Letters   48 ( 22 )   3809 - 3812   2007.5

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    Two new Daphniphyllum alkaloids, calyciphyllines E (1) and F (2), have been isolated from the leaves of Daphniphyllum calycinum (Daphniphyllaceae), and the structures and relative stereochemistry were elucidated on the basis of spectroscopic data. (C) 2007 Elsevier Ltd. All rights reserved.

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  • Amphidinolactone a, a new 13-membered macrolide from dinoflagellate Amphidinium sp. Reviewed

    Yohei Takahashi, Takaaki Kubota, Jun'ichi Kobayashi

    Heterocycles   72   567 - 572   2007.4

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    A new 13-membered macrolide, amphidinolactone A (1), has been isolated from a marine dinoflagellate Amphidinium sp., and the structure and relative stereochemistry were elucidated by spectroscopic data. Amphidinolactone A (1) is the first macrolide without a branched methyl or an exomethylene among all the macrolides isolated from the dinoflagellates so far.

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  • Calyciphylline D, a novel alkaloid with an unprecedented fused-pentacyclic skeleton from daphniphyllum calycinum Reviewed

    Shizuka Saito, Takaaki Kubota, Eri Fukushi, Jun Kawabata, Huiping Zhang, Jun'ichi Kobayashi

    Organic Letters   9 ( 7 )   1207 - 1209   2007.3

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    Calyciphylline D (1), a novel Daphniphyllum alkaloid with an unprecedented fused-pentacyclic skeleton containing a 8-azatricyclo[4.2.1.0.(4,8)]nonane ring system, has been isolated from the leaves of Daphniphyllum calycinum (Daphniphyllaceae), and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data.

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  • Bioactive macrolides and polyketides from marine dinoflagellates of the genus Amphidinium Reviewed

    Jun'ichi Kobayashi, Takaaki Kubota

    Journal of Natural Products   70 ( 3 )   451 - 460   2007.3

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    Marine microorganisms such as bacteria, cyanobacteria, dinoflagellates, and others have attracted many natural product chemists as the real producers of marine toxins such as fish and algal poisons as well as bioactive substances isolated from marine invertebrates such as sponges and tunicates. Among marine microorganisms, dinoflagellates have proved to be important sources of marine toxins and have been investigated worldwide by natural product chemists. We have continued investigations on chemically interesting and biologically significant secondary metabolites from Amphidinium spp., of a genus of symbiotic marine dinoflagellates separated from inside cells of Okinawan marine flatworms. This review covers the results described in our recent publications on a series of cytotoxic macrolides, designated amphidinolides, and long-chain polyketides isolated from Amphidinium spp. In this review, topics include the isolation, structure elucidation, synthesis, biosynthesis, and bioactivity of amphidinolides and long-chain polyketides.

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  • Calyciphylline C, a novel Daphniphyllum alkaloid from Daphniphyllum calycinum Reviewed

    Shizuka Saito, Takaaki Kubota, Eri Fukushi, Jun Kawabata, Huiping Zhang, Jun'ichi Kobayashi

    Tetrahedron Letters   48 ( 9 )   1587 - 1589   2007.2

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    Calyciphylline C (1), a novel Daphniphyllum alkaloid with unprecedented fused-hexacyclic ring system, has been isolated from the leaves of Daphniphyllum calycinum (Daphniphyllaceae), and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data. (c) 2007 Elsevier Ltd. All rights reserved.

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  • Complanadines C and D, new dimeric alkaloids from Lycopodium complanatum Reviewed

    Kan'ichiro Ishiuchi, Takaaki Kubota, Yuzuru Mikami, Yutaro Obara, Norimichi Nakahata, Jun'ichi Kobayashi

    Bioorganic and Medicinal Chemistry   15 ( 1 )   413 - 417   2007.1

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    Two new dimeric Lycopodium alkaloids, complanadines C (1) and D (2), have been isolated from the club moss Lycopodium complanatum, and the structures and relative stereochemistry of I and 2 were elucidated on the basis of the spectral data. Complanadine D (2) enhanced mRNA expression for NGF. (c) 2006 Elsevier Ltd. All rights reserved.

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  • Pyrinadines B-G, new bis-pyridine alkaloids with an azoxy moiety from sponge Cribrochalina sp. Reviewed

    Yuuko Kariya, Takaaki Kubota, Jane Fromont, Jun'ichi Kobayashi

    Bioorganic and Medicinal Chemistry   14 ( 24 )   8415 - 8419   2006.12

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    Six new cytotoxic bis-3-alkylpyridine alkaloids with an azoxy moiety, pyrinadines B-G (1-6), have been isolated from an Okinawan marine sponge Cribrochalma sp., and the structures were elucidated by spectroscopic data and chemical means. (c) 2006 Elsevier Ltd. All rights reserved.

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  • Lycovatine A, a C<inf>16</inf>N-type quaternary alkaloid from Lycopodium clavatum var. Robustum Reviewed

    Takaaki Kubota, Tomoe Sunaura, Hiroshi Morita, Yuzuru Mikami, Tomohiro Hoshino, Yutaro Obara, Norimichi Nakahata, Jun'ichi Kobayashi

    Heterocycles   69 ( 1 )   469 - 474   2006.12

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    A new C16N-type quaternary alkaloid, lycovatine A (1), has been isolated from the club moss Lycopodium clavatum var. robustum, and the structure including the relative stereochemistry was elucidated on the basis of spectroscopic data.

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  • Brasilicardin A, a Natural Immunosuppressant, Targets Amino Acid Transport System L Reviewed

    Takeo Usui, Yoko Nagumo, Ai Watanabe, Takaaki Kubota, Kazusei Komatsu, Jun'ichi Kobayashi, Hiroyuki Osada

    Chemistry and Biology   13 ( 11 )   1153 - 1160   2006.11

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    Lymphocytes in T cell activation require extracellular nutrients to provide energy for cellular proliferation and effector functions. Therefore, inhibitors of nutrient transporters are expected to be a new class of immunosuppressant. Here, we report that the molecular target of brasilicardin A (BraA), an immunosuppressive compound, is the amino acid transporter system L. BraA inhibited the cell-cycle progression of murine T cell lymphocyte CTLL-2 cells in G1 phase, and potently inhibited the uptake of amino acids that are substrates for amino acid transport system L. Moreover, BraA stimulated the GCN2 activation and, subsequently, the phosphorylation of eIF2 alpha. These results suggest that the immunosuppressive activity of BraA is induced by amino acid deprivation via the inhibition of system L and that the amino acid transporter is a target for immunosuppressant.

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  • Paratunamides A-D, oxindole alkaloids from Cinnamodendron axillare Reviewed

    Toshinori Kagata, Shizuka Saito, Hideyuki Shigemori, Ayumi Ohsaki, Haruaki Ishiyama, Takaaki Kubota, Jun'ichi Kobayashi

    Journal of Natural Products   69 ( 10 )   1517 - 1521   2006.10

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    Four new oxindole alkaloids, paratunamides A-D (1-4), containing a secologanin unit, were isolated from the bark of Cinnamodendron axillare, and their structures and relative configurations were elucidated by spectroscopic data. The absolute configuration at C-7 in 1-4 was assigned as S, S, R, and S, respectively, on the basis of the CD spectra.

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  • Lycopladines B-D and lyconadin B, new alkaloids from Lycopodium complanatum Reviewed

    Kan'ichiro Ishiuchi, Takaaki Kubota, Tomohiro Hoshino, Yutaro Obara, Norimichi Nakahata, Jun'ichi Kobayashi

    Bioorganic and Medicinal Chemistry   14 ( 17 )   5995 - 6000   2006.9

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    Four new alkaloids, lycopladines B-D (1-3) and lyconadin B (4), have been isolated from the club moss Lycopodium complanatum and the structures including the stereochemistry were elucidated on the basis of spectral data and modified Mosher's method. Lyconadin B (4) elevated NGF mRNA expression in 1321N1 human astrocytoma cells. (c) 2006 Elsevier Ltd. All rights reserved.

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  • Determination of the cryptic stereochemistry of the first PKS chain-extension step in ansamitocin biosynthesis by Actinosynnema pretiosum Reviewed

    Takaaki Kubota, Marco Brünjes, Thomas Frenzel, Jun Xu, Andreas Kirschning, Heinz G. Floss

    ChemBioChem   7 ( 8 )   1221 - 1225   2006.8

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    The biosynthesis of the antitumor antibiotic, ansamitocin, involves the assembly of a linear octaketide on the ansamitocin (asm) polyketide synthase (PKS), which is then cyclized to proansamitocin and further modified to the final product. In the first chain-extension step on the asm PKS, a stereocenter is generated which is then obliterated in a subsequent double-bond migration. The cryptic configuration at this stereocenter was determined by first synthesizing the two enantiomers of the intermediate diketide as their N-acetylcysteamine (SNAC) thioesters. These were then used to demonstrate that only the R enantiomer complements a 3-amino-5-hydroxybenzoic acid (AHBA) deficient mutant of Actinosynnema pretiosum to restore ansomitocin formation. The low efficiency of complementation by the diketide, compared to AHBA, is due to inefficient loading onto the PKS and not the inhibition of the enzyme. A presumed next chain-extension intermediate-the triketide with an unrearranged double bond-was also synthesized as its SNAC ester, but did not complement the AHBA(-) mutant.

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  • Amphidinin B, a new polyketide metabolite from marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Tetsuya Endo, Yohei Takahashi, Masashi Tsuda, Jun'ichi Kobayashi

    Journal of Antibiotics   59 ( 8 )   512 - 516   2006.8

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    A new polyketide metabolite, amphidinin B (1), has been isolated from a marine dinoflagellate Amphidinium sp. and the structure and absolute stereochemistry were elucidated on the basis of spectroscopic data and chemical means.

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  • Amphidinin B, a new polyketide metabolite from marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Tetsuya Endo, Yohei Takahashi, Masashi Tsuda, Jun&apos;ichi Kobayashi

    JOURNAL OF ANTIBIOTICS   59 ( 8 )   512 - 516   2006.8

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    A new polyketide metabolite, amphidinin B (1), has been isolated from a marine dinoflagellate Amphidinium sp. and the structure and absolute stereochemistry were elucidated on the basis of spectroscopic data and chemical means.

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  • Cloning of polyketide synthase genes from amphidinolide-producing dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Yoshiro Iinuma, Jun'ichi Kobayashi

    Biological and Pharmaceutical Bulletin   29 ( 7 )   1314 - 1318   2006.7

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    Cloning of polyketide synthase (PKS) gene for amphidinolide biosynthesis was attempted from a dinoflagellate Amphidinium sp. (strain Y-42). Fourteen beta-ketoacyl synthase gene fragments were obtained by Polymerase Chain Reaction (PCR) amplification from degenerated primer sets designed on the basis of the conserved amino acid sequences of beta-ketoacyl synthase domains in known type I PKSs. The PCR analysis using primer sets designed from these fourteen beta-ketoacyl synthase gene fragments revealed that these DNA sequences exist only in the dinoflagellates producing amphidinolides. The DNA sequence of the positive clone, which was isolated from genomic DNA library of Amphidinium sp. (strain Y-42) by PCR detection using the specific primer set, was analyzed by shotgun sequencing. The deduced gene products in the positive clone showed similarity with beta-ketoacyl synthase (KS), acyl transferase (AT), dehydratase (DH), ketoreductase (KR), and acyl carrier protein (ACP) in known type I PKSs and thioesterase (TE).

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  • Amphezonol A, a novel polyhydroxyl metabolite from marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Yusuke Sakuma, Kazutaka Shimbo, Masashi Tsuda, Michiko Nakano, Yasuhiro Uozumi, Jun'ichi Kobayashi

    Tetrahedron Letters   47 ( 26 )   4369 - 4371   2006.6

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    Amphezonol A (1), a novel polyhydroxyl linear carbon-chain metabolite, has been isolated from the cultured marine dinoflagellate Amphidinium sp., which was isolated from an Okinawan marine acoel flatworm Amphiscolops sp. The structure of 1 was elucidated by detailed analyses of 2D NMR spectra. Amphezonol A (1) possesses one tetrahydrofuran ring, two tetrahydropyran rings, and twenty-one hydroxyl groups on C-60-linear aliphatic chain with one exo-methylene and one methyl branch. Amphezonol A (1) exhibited a modest inhibitory activity against DNA polymerase alpha. (c) 2006 Elsevier Ltd. All rights reserved.

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  • Iejimalides show anti-osteoclast activity via V-ATPase inhibition Reviewed

    Sayaka Kazami, Makoto Muroi, Makoto Kawatani, Takaaki Kubota, Takeo Usui, Jun'ichi Kobayashi, Hiroyuki Osada

    Bioscience, Biotechnology and Biochemistry   70 ( 6 )   1364 - 1370   2006.6

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    Iejimalides (IEJLs), 24-membered macrolides, are potent antitumor compounds, but their molecular targets remain to be revealed. In the course of screening, we identified IEJLs as potent osteoclast inhibitors. Since it is known that osteoclasts are sensitive to vacuolar H+-ATPase (V-ATPase) inhibitor, we investigated the effect of IEJLs on V-ATPases. IEJLs inhibited the V-ATPases of both mammalian and yeast cells in situ, and of. yeast V-ATPases in vitro. A bafilomycin-resistant yeast mutant conferred IEJL resistance, suggesting that IEJLs bind a site similar to the bafilomycins/concanamycins-binding site. These results indicate that IEJLs are novel V-ATPase inhibitors, and that antitumor and antiosteporotic activities are exerted via V-ATPase inhibition.

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  • Daphtenidines A-D, new Daphniphyllum alkaloids from Daphniphyllum teijsmannii Reviewed

    Takaaki Kubota, Yosuke Matsuno, Hiroshi Morita, Takakazu Shinzato, Mitsuhiro Sekiguchi, Jun'ichi Kobayashi

    Tetrahedron   62 ( 20 )   4743 - 4748   2006.5

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    Daphtenidines A-D (1-4), four new alkaloids were isolated from the leaves of Daphniphyllum teijsmannii, and the structures including relative stereochemistry were elucidated on the basis of spectroscopic data. Daphtenidines A (1) and B (2) were possessing daphnilactone A-type skeleton. This is the second isolation of daphnilactone A-type alkaloids from natural sources. Daphtenidine C (3) was 4-acetoxy form of daphmanidin A, while daphtenidine D (4) was 14-dehydro form of yuzurimine. (c) 2006 Elsevier Ltd. All rights reserved.

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  • Lycopladine A, a new C<inf>16</inf>N alkaloid from Lycopodium complanatum Reviewed

    Kan'ichiro Ishiuchi, Takaaki Kubota, Hiroshi Morita, Jun'ichi Kobayashi

    Tetrahedron Letters   47 ( 19 )   3287 - 3289   2006.5

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    A new C16N type alkaloid, lycopladine A (1), has been isolated from the club moss Lycopodium complanatum, and the structure and relative stereochemistry of 1 were elucidated on the basis of spectral data. (c) 2006 Elsevier Ltd. All rights reserved.

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  • Manzamenones inhibit T-cell protein tyrosine phosphatase Reviewed

    Yusuke Wakuda, Takaaki Kubota, Hiroshi Shima, Tadashi Okada, Shinya Mitsuhashi, Naohito Aoki, Kunimi Kikuchi, Jun'ichi Kobayashi

    Marine Drugs   4 ( 1 )   9 - 14   2006.3

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    Manzamenones A similar to C (1 similar to 3) and E similar to F (5 similar to 6), unique oxylipin metabolites isolated from a marine sponge Plakortis sp., have been found to exhibit inhibitory activity against T-cell protein tyrosine phosphatase (TCPTP). The inhibitory activity of 2 and 5 against TCPTP was 4 times more potent than that against protein tyrosine phosphatase-1B (PTP1B).

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  • Pyrinadine A, a novel pyridine alkaloid with an azoxy moiety from sponge Cribrochalina sp. Reviewed

    Yuuko Kariya, Takaaki Kubota, Jane Fromont, Jun'ichi Kobayashi

    Tetrahedron Letters   47 ( 6 )   997 - 998   2006.2

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    A novel cytotoxic bis-3-alkylpyridine alkaloid with an azoxy moiety, pyrinadine A (1), has been isolated from an Okinawan marine sponge Cribrochalina sp. (SS-1115), and the structure was elucidated by spectroscopic data and chemical means. (c) 2005 Elsevier Ltd. All rights reserved.

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  • Luteophanol D, new polyhydroxyl metabolite from marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Ayako Takahashi, Masashi Tsuda, Jun'ichi Kobayashi

    Marine Drugs   3 ( 4 )   113 - 118   2005.12

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    Luteophanol D ( 1), a new polyhydroxyl linear carbon-chain metabolite, has been isolated from the cultured marine dinoflagellate Amphidinium sp., which was isolated from Okinawan marine acoel flatworm Pseudaphanostoma luteocoloris. The structure of 1 was elucidated by detailed analyses of 2D NMR spectra. Luteophanol D ( 1) possesses two tetrahydropyran rings and twenty-three hydroxyl groups on C-63-linear aliphatic chain with one exo-methylene and two methyl branches.

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  • Amphidinolide C2, new macrolide from marine dinoflagellate amphidinium species Reviewed

    Takaaki Kubota, Yusuke Sakuma, Masashi Tsuda, Jun’Ichi Kobayashi

    Marine Drugs   2 ( 3 )   83 - 87   2004.9

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    A new cytotoxic 25-membered macrolide, amphidinolide C2 (1), has been isolated from marine dinoflagellate Amphidinium sp. (Y-71 strain), and the structure 1 was elucidated on the basis of spectroscopic data and chemical means.

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  • Absolute stereochemistry of amphidinolide C: Synthesis of C-1-C-10 and C-17-C-29 segments Reviewed

    Takaaki Kubota, Masashi Tsuda, Jun'ichi Kobayashi

    Tetrahedron   59 ( 10 )   1613 - 1625   2003.3

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    Two of each diastereomers of the C-1-C-10 and C-17-C-29 segments of amphidinolide C (1) were synthesized. Comparing the H-1 NMR chemical shifts of its MTPA esters with those of linear methyl ester of 1, the absolute configurations at C-7, C-8, C-20, C-23, and C-24 in amphidinolide C (1) were confirmed to be all R. (C) 2003 Elsevier Science Ltd. All rights reserved.

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  • Bioactive macrolides and polyketides from marine dinoflagellates Reviewed

    Jun'ichi Kobayashi, Kazutaka Shimbo, Takaaki Kubota, Masashi Tsuda

    Pure and Applied Chemistry   75 ( 2-3 )   337 - 342   2003

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    Absolute stereochemistry of amphidinolides G and H, potent cytotoxic 27- and 26-membered macrolides, respectively, isolated from a marine dinofiagellate Amphidinium sp., was determined by X-ray diffraction analysis, synthesis of a degradation product, and chemical interconversion. Six new macrolides, amphidinolides H2∼H5, G2, G3, and W, have been isolated from a marine dinoflagellate Amphidinium sp. (strain Y-42), and the structures were elucidated by 2D NMR data and chemical means. The structure-activity relationship of amphidinolide H-type macrolides for cytotoxicity was examined. The biosynthetic origins of amphidinolides B, C, H, J, T1, and W were investigated on the basis of 13C NMR data of 13C-enriched samples obtained by feeding experiments with [1-13C], [2-13C], and [1,2-13C2] sodium acetates in cultures of the dinoflagellates. Five novel long-chain polyhydroxyl compounds, colopsinols A∼E, were obtained from the Amphidinium sp. (strain Y-5).

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  • Absolute stereochemistry of amphidinolide E Reviewed

    Takaaki Kubota, Masashi Tsuda, Jun'ichi Kobayashi

    Journal of Organic Chemistry   67 ( 5 )   1651 - 1656   2002.3

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    The absolute configurations at eight chiral centers in amphidinolide E (1), a cytotoxic 19-membered macrolide isolated from a marine dinoflagellate Amphidinium sp., were determined to be 2R, 7R, 8R, 13S, 16S, 17R, 18R, and 19R on the basis of detailed analysis of NMR data and by chemical means.

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  • Biosynthetic study of amphidinolide B Reviewed

    M. Tsuda, T. Kubota, Y. Sakuma, J. Kobayashi

    Chemical and Pharmaceutical Bulletin   49 ( 10 )   1366 - 1367   2001.10

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    The biosynthetic origins of amphidinolide B (1) were investigated on the basis of C-13-NMR data of C-13-enriched samples obtained by feeding experiments with [1-C-13], [2-C-13], and [1,2-C-13(2)] sodium acetates in cultures of a dinoflagellate Amphidinium sp. These incorporation patterns suggested that 1 was generated from three successive polyketide chains, an isolated C-1 unit from C-2 of acetates, six branched C-1 units from C-2 of acetates, and an "m-m" and an "m-m-m" unit derived only from C-2 of acetates. The labeling patterns of amphidinolide B (1) were different from those of amphidinolide H (2), a 26-membered macrolide closely related to 1.

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  • Amphidinolide T5, a new 19-membered macrolide from a dinoflagellate and X-ray structure of amphidinolide T1 Reviewed

    Takaaki Kubota, Tetsuya Endo, Masashi Tsuda, Motoo Shiro, Jun'Ichi Kobayashi

    Tetrahedron   57 ( 29 )   6175 - 6179   2001.7

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    Amphidinolide T5 (1), a new 19-membered macrolide related to amphidinolide T1 (2), has been isolated from a marine dinoflagellate Amphidinium sp. The structure of 1 was elucidated on the basis of spectroscopic data and chemical means. The stereostructure of amphidinolide T1 (2) was confirmed by a single crystal X-ray diffraction analysis. (C) 2001 Elsevier Science Ltd. All rights reserved.

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  • Biosynthetic study of amphidinolide C Reviewed

    Takaaki Kubota, Masashi Tsuda, Jun'ichi Kobayashi

    Tetrahedron   57 ( 28 )   5975 - 5977   2001.7

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    The biosynthetic origins of amphidinolide C (1) were investigated on the basis of C-13 NMR data of C-13 enriched samples obtained by feeding experiments with [1-C-13], [2-C-13], and [1,2-(13)C2] sodium acetates in cultures of a dinoflagellate Amphidinium sp. These incorporation patterns suggested that amphidinolide C (1) was generated from four diketide chains, four acetate units, five isolated C-1 unit from C-2 of acetates, seven branched C-1 units from C-2 of acetates, and a 'm-m' and a 'm-m-m' units derived only from C-2 of acetates. (C) 2001 Elsevier Science Ltd. All rights reserved.

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  • Absolute stereochemistry of amphidinolide C Reviewed

    Takaaki Kubota, Masashi Tsuda, Jun'ichi Kobayashi

    Organic Letters   3 ( 9 )   1363 - 1366   2001.5

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    The absolute configurations at 12 chiral centers in amphidinolide C (1), a potent cytotoxic 25-membered macrolide isolated from a marine dinoflagellate Amphidinium sp,, were determined to be 3S, 4R, 6R, 7R, 8R, 12R 135, 16S, 20R, 23R, 24R, and 29S by combination of NMR analyses, degradation experiments, and synthesis of the C-1-C-7 segment.

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  • Amphidinolides T2, T3, and T4, new 19-membered macrolides from the dinoflagellate Amphidinium sp. and the biosynthesis of amphidinolide T1 Reviewed

    J. Kobayashi, T. Kubota, T. Endo, M. Tsuda

    Journal of Organic Chemistry   66 ( 1 )   134 - 142   2001.1

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    Three new 19-membered macrolides, amphidinolides T2 (2), T3 (3), and T4 (4), structurally related to amphidinolide T1 (1) have been isolated from two strains of marine dinoflagellates of the genus Amphidinium. The structures of 2-4 were elucidated on the basis of spectroscopic data. The absolute configurations at C-7, C-8, and C-10 of 1-4 were determined by comparison of NMR data of their C-1-C-12 segments with those of synthetic model compounds for the tetrahydrofuran portion. The biosynthetic origins of amphidinolide TI (1) were investigated on the basis of C-13 NMR data of a C-13 enriched sample obtained by feeding experiments with [1-C-13], [2-C-13], and [1,2-C-13(2)] sodium acetates and C-13-labeled sodium bicarbonstte in the cultures of the dinoflagellate. These incorporation patterns suggested that amphidinolide T1 (1) was generated from four successive palyketide chains, an isolated C-1 unit formed from C-2 of acetates, and three unusual Ct units derived only from C-2 of acetates. Furthermore, it is noted that five oxygenated carbons of C-l, C-7, C-12, C-13, and C-18 were not derived from the C-1 carbonyl, but from the C-2 methyl of acetates.

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  • Ma'edamines A and B, cytotoxic bromotyrosine alkaloids with a unique 2(1H)pyrazinone ring from sponge Suberea sp. Reviewed

    Keiko Hirano, Takaaki Kubota, Masashi Tsuda, Kenji Watanabe, Jane Fromont, Jun'ichi Kobayashi

    Tetrahedron   56 ( 41 )   8107 - 8110   2000.10

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    Two new cytotoxic bromotyrosine alkaloids, ma'edamines A (1) and B (2), with a unique 2(1H)pyrazinone ring have been isolated from the Okinawan marine sponge Suberea sp. The structures were elucidated on the basis of spectroscopic data. (C) 2000 Elsevier Science Ltd. All rights reserved.

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  • Colopsinols D and E, new polyhydroxyl linear carbon chain compounds from marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Masashi Tsuda, Miho Takahashi, Masami Ishibashi, Seiko Oka, Jun'ichi Kobayashi

    Chemical and Pharmaceutical Bulletin   48 ( 10 )   1447 - 1451   2000.10

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    Colopsinols D (1) and E (2), two new polyhydroxyl linear carbon chain compounds, have been isolated from the cultured marine dinoflagellate Amphidinium sp. The structures of 1 and 2 were elucidated on the basis of two-dimensional NMR and FAB-MS/MS data.

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  • Pyrinodemins B-D, potent cytotoxic bis-pyridine alkaloids from marine sponge Amphimedon sp.

    K Hirano, T Kubota, M Tsuda, Y Mikami, J Kobayashi

    CHEMICAL & PHARMACEUTICAL BULLETIN   48 ( 7 )   974 - 977   2000.7

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    New bis-pyridine alkaloids, pyrinodemins B-D (1-3), have been isolated together with pyrinodemin A (4) and related 3-alkyl pyridine alkaloids 5-8 from the Okinawan marine sponge Amphimedon sp. and the structures were elucidated from spectroscopic data. Pyrinodemins B-D (1-3) showed potent cytotoxicity, while compounds 5-8 exhibited antimicrobial activity.

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  • Pyrinodemins B - D, potent cytotoxic bis-pyridine alkaloids from marine sponge Amphimedon sp. Reviewed

    Keiko Hirano, Takaaki Kubota, Masashi Tsuda, Yuzuru Mikami, Jun'ichi Kobayashi

    Chemical and Pharmaceutical Bulletin   48 ( 7 )   974 - 977   2000.7

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    New bis-pyridine alkaloids, pyrinodemins B-D (1-3), have been isolated together with pyrinodemin A (4) and related 3-alkyl pyridine alkaloids 5-8 from the Okinawan marine sponge Amphimedon sp. and the structures were elucidated from spectroscopic data. Pyrinodemins B-D (1-3) showed potent cytotoxicity, while compounds 5-8 exhibited antimicrobial activity.

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  • Amphidinolide V, novel 14-membered macrolide from marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Masashi Tsuda, Jun'ichi Kobayashi

    Tetrahedron Letters   41 ( 5 )   713 - 716   2000.1

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    A novel 14-membered polyene macrolide, amphidinolide V (1), has been isolated from a marine dinoflagellate Amphidinium sp., and the structure was elucidated by spectroscopic data. The relative stereochemistry of C-8, C-9, C-10, and C-13 was elucidated by NOESY correlations. Amphidinolide V (1) possessing five exo-methylenes and one epoxide exhibited cytotoxicity against tumor cell lines. (C) 2000 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(99)02170-X

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  • Colopsinols B and C, new long chain polyhydroxy compounds from cultured marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Masashi Tsuda, Miho Takahashi, Masami Ishibashi, Hideo Naoki, Jun'ichi Kobayashi

    Journal of the Chemical Society - Perkin Transactions 1   ( 23 )   3483 - 3487   1999.12

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    Colopsinols B (1) and C (2), unique polyhydroxy compounds consisting of a C-53-linear aliphatic chain with three C-1 branches, three ether rings, six hydroxy groups, a glucoside moiety, and a sulfate ester have been isolated from the cultured marine dinoflagellate Amphidinium sp. The structures of 1 and 2 were elucidated on the basis of extensive NMR techniques as well as FABMS/MS data of the peroxide (3) of 2.

    DOI: 10.1039/a906296c

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  • Two theonellapeptolide congeners from marine sponge Theonella sp. Reviewed

    Masashi Tsuda, Kazutaka Shimbo, Takaaki Kubota, Yuzuru Mikami, Jun'ichi Kobayashi

    Tetrahedron   55 ( 34 )   10305 - 10314   1999.8

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    Two new theonellapeptolide-related cyclic depsipeptides (1 and 2) have been isolated from an Okinawan marine sponge Theonella sp. and the structures were elucidated on the basis of the 2D NMR data, PSD analysis of MALDI-TOFMS, and chemical means. Compound 1 was a theonellapeptolide congener possessing a methylsulfinylacetyl group at the N-terminus, while 2 was another theonellapeptolide congener having an acetyl group at the N-terminus. Compounds 1 and 2 exhibited antimicrobial activity. (C) 1999 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4020(99)00586-4

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  • Pyrinodemin A, a cytotoxic pyridine alkaloid with an isoxazolidine moiety from sponge Amphimedon sp. Reviewed

    Masashi Tsuda, Keiko Hirano, Takaaki Kubota, Jun'ichi Kobayashi

    Tetrahedron Letters   40 ( 26 )   4819 - 4820   1999.6

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    A novel cytotoxic pyridine alkaloid, pyrinodemin A (1), with a unique cis-cyclopent[c]isoxazolidine moiety has been isolated from the Okinawan marine sponge Amphimedon sp., and the structure was elucidated from 2D NMR data and EIMS fragmentation. (C) 1999 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(99)00852-7

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  • Pyrinodemin A, a cytotoxic pyridine alkaloid with an isoxazolidine moiety from sponge Amphimedon sp. Reviewed

    M Tsuda, K Hirano, T Kubota, J Kobayashi

    TETRAHEDRON LETTERS   40 ( 26 )   4819 - 4820   1999.6

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    A novel cytotoxic pyridine alkaloid, pyrinodemin A (1), with a unique cis-cyclopent[c]isoxazolidine moiety has been isolated from the Okinawan marine sponge Amphimedon sp., and the structure was elucidated from 2D NMR data and EIMS fragmentation. (C) 1999 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4039(99)00852-7

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    Other Link: http://orcid.org/0000-0002-3553-5844

  • Colopsinol A, a novel polyhydroxyl metabolite from marine dinoflagellate Amphidinium sp. Reviewed

    Jun'ichi Kobayashi, Takaaki Kubota, Miho Takahashi, Masami Ishibashi, Masashi Tsuda, Hideo Naoki

    Journal of Organic Chemistry   64 ( 5 )   1478 - 1482   1999.3

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    Colopsinol A (1), a novel polyhydroxyl compound, has been isolated from the cultured marine dinoflagellate Amphidiniun sp., from which a number of cytotoxic macrolides, amphidinolides, have been obtained to date, and the gross structure of 1 was elucidated on the basis of extensive spectroscopic analyses including recent 2D NMR techniques of CH2-seIected editing HSQC as well as FABMS/MS experiments and chemical means. Colopsinol A (1), C71H119O25SNa, is the first member of a new class of polyketide natural products possessing a gentiobioside moiety and a sulfate eater. The polyketide aglycon consisted of a C-56-linear aliphatic chain with one exo-methylene and two methyl branches as well as two ketones, five hydroxyl groups, and a tetrahydropyran and two epoxide rings.

    DOI: 10.1021/jo981882b

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  • Colopsinols B and C, new long chain polyhydroxy compounds from cultured marine dinoflagellate Amphidinium sp.

    T Kubota, M Tsuda, M Takahashi, M Ishibashi, H Naoki, J Kobayashi

    JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1   40 ( 23 )   3483 - 3487   1999

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    Colopsinols B (1) and C (2), unique polyhydroxy compounds consisting of a C-53-linear aliphatic chain with three C-1 branches, three ether rings, six hydroxy groups, a glucoside moiety, and a sulfate ester have been isolated from the cultured marine dinoflagellate Amphidinium sp. The structures of 1 and 2 were elucidated on the basis of extensive NMR techniques as well as FABMS/MS data of the peroxide (3) of 2.

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  • Luteophanols B and C, new polyhydroxyl compounds from marine dinoflagellate Amphidinium sp. Reviewed

    Takaaki Kubota, Masashi Tsuda, Yukiko Doi, Ayako Takahashi, Hiroko Nakamichi, Masami Ishibashi, Eri Fukushi, Jun Kawabata, Jun'ichi Kobayashi

    Tetrahedron   54 ( 48 )   14455 - 14464   1998.11

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    Luteophanols B (1) and C (2), new polyhydroxyl linear carbon-chain compounds, have been isolated from the cultured marine dinoflagellate Amphidinium sp. The structures of 1 and 2 were elucidated by detailed analyses of two-dimensional NMR data containing HMBC, HMQC-RELAY, CH2-selected E-HSQC, and CH2-selected E-HSQC, TOCSY. (C) 1998 Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0040-4020(98)00898-9

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  • パートナー天然物化学(改訂第4版増補)

    森田, 博史, 阿部, 郁朗( Role: Contributor)

    南江堂  2023.12  ( ISBN:9784524404513

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  • パートナー天然物化学(改訂第4版)

    森田, 博史, 阿部, 郁朗( Role: Contributor)

    南江堂  2021.8  ( ISBN:9784524403776

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  • パートナー天然物化学(改訂第3版)

    海老塚, 豊, 森田, 博史, 阿部, 郁朗( Role: Contributor)

    南江堂  2016.9  ( ISBN:9784524403325

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  • パートナー天然物化学(改訂第2版)

    海老塚, 豊, 森田, 博史( Role: Contributor)

    南江堂  2012.1  ( ISBN:9784524402793

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  • Comprehensive Natural Products II: Chemistry and Biology

    Elsevier Science  2010 

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  • パートナー天然物化学

    海老塚, 豊, 森田, 博史( Role: Contributor)

    南江堂  2007.4  ( ISBN:9784524402250

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    Total pages:xv, 330p   Language:Japanese

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  • Cooperation of Bio and Nano Sciences, II. Application to New Life Sciences

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MISC

  • 沖縄産Amphimedon属海綿から単離した新規マンザミン関連アルカロイドZamamiphidin BおよびCの構造

    栗本慎一郎, 鈴木祥一, 上野真由美, 小林淳一, 久保田高明

    第65回天然有機化合物討論会   2023.9

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  • 五環性トリテルペンursolic acidの抗歯周病原細菌活性および細胞毒性の評価

    佐藤 祐太郎, 石原 和幸, 久保田 高明

    Journal of Oral Biosciences Supplement   2023   [O3 - 03]   2023.9

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  • Search for inhibitors of advanced glycation end products formation from brown algae, Sargassum macrocarpum and Ecklonia stolonifera

    Seiya Shinoda, Arisa Uno, Tomoya Masaki, Tetsuya Sasaki, Haruaki Ishiyama, Shin-ichiro Kurimoto, Takaaki Kubota, Mitsuhiro Sekiguch

    22nd IUNS-ICN International Congress of Nutrition in Tokyo, Japan   2022.12

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  • ビルベリー由来抗歯周病原細菌活性物質の精製と同定(Purification and identification of an anti-periodontal pathogenic-bacterial active substance derived from bilberry)

    佐藤 祐太郎, 石原 和幸, 久保田 高明

    Journal of Oral Biosciences Supplement   2022   115 - 115   2022.9

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  • New bromotyrosine alkaloids from an Okinawan marine sponge Suberea sp.

    栗本慎一郎, 栗本慎一郎, 岡本彩乃, 清野皐月, 小林淳一, 久保田高明, 久保田高明

    日本薬学会年会要旨集(Web)   142nd   2022

  • Structure and bioactivity of new meroterpenoid from Sargassum macrocarpum

    篠田清哉, 栗本慎一郎, 久保田高明, 関口光広

    食品薬学シンポジウム講演要旨集   9th (CD-ROM)   2022

  • 能登産海藻Sargassum macrocarpumより単離した新規メロテルペノイド化合物の構造とAGEs生成阻害活性評価

    篠田清哉, 丹羽裕美, 栗本慎一郎, 久保田高明, 関口光広, 関口光広

    日本生薬学会年会講演要旨集   67th   2021

  • Structure and bioactivity of polyhydroxy sterols from an Okinawan marine sponge Dysidea sp.

    栗本慎一郎, 石塚芽衣菜, 武田郁恵, 矢口貴志, 小林淳一, 久保田高明, 久保田高明

    日本薬学会年会要旨集(Web)   141st   2021

  • New diterpene alkaloid from an Okinawan marine sponge Agelas sp.

    近藤和幸, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   140th (Web)   2020

  • New manzamine-related alkaloid from an Okinawan marine sponge Amphimedon sp.

    栗本慎一郎, 鈴木祥一, 上野真由美, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   140th (Web)   2020

  • New steroid from an Okinawan marine sponge Halichondria sp.

    森光希, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   140th (Web)   2020

  • Preparation of sesquiterpenoid quinone derivatives for structure activity relationship study

    島田祐莉奈, 小川実華, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   140th (Web)   2020

  • Sesquiterpenoid quinone from an Okinawan marine sponge of the family Spongiidae

    猪俣実加, 小川実華, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   140th (Web)   2020

  • Search for anti-glycation agents from “Abokyu“, a cultivar of edible Chrysanthemum

    水野実穂, 栗本慎一郎, 中村隆典, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   140th   2020

  • 渦鞭毛藻Symbiodinium sp.から単離した新規マクロリドの構造

    石田理紗, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   139th   2019

  • 沖縄産Suberea属海綿から単離した新規ブロモチロシンアルカロイドの構造

    清野皐月, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   139th   2019

  • 沖縄産Stylissa属海綿から単離した新規環状ペプチドの構造

    大山英将, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   139th   2019

  • 渦鞭毛藻Amphidinium sp.から単離した新規ポリケチドの構造

    坂根美和子, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   139th   2019

  • 沖縄産Plakortis属海綿から単離した新規ポリケチドの構造

    木村悠登, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   139th   2019

  • 沖縄産Hyrtios属海綿から単離した新規β-カルボリンアルカロイドの構造

    高橋秀彰, 栗本慎一郎, 小林淳一, 久保田高明

    天然薬物の開発と応用シンポジウム講演要旨集   22nd   2018

  • 沖縄産Hyrtios属海綿から単離した新規Canthin-6-oneアルカロイドの構造

    高橋秀彰, 栗本慎一郎, 小林淳一, 久保田高明

    日本生薬学会年会講演要旨集   65th   2018

  • 沖縄産Dysidea属海綿から単離した新規ポリヒドロキシステロールの構造

    武田郁恵, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   138th   2018

  • 沖縄産Hyrtios属海綿から単離した新規インドールアルカロイドの構造

    高橋秀彰, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   138th   2018

  • 沖縄産Pseudoceratina属海綿から単離した新規ブロモチロシンアルカロイドの構造

    大野泰斗, 栗本慎一郎, 小林淳一, 久保田高明

    日本薬学会年会要旨集(CD-ROM)   138th   2018

  • Zamamiphidin A and Zamamidine D, New Manzamine Alkaloids from Okinawan Marine Sponge Amphimedon sp.

    久保田高明, 栗本慎一郎, 上條優樹, 中村健太, 酒井香奈江, 高橋梓, 穗苅玲, 石山亜紀, 岩月正人, 乙黒一彦, 五ノ井透, 大村智, 小林淳一

    天然有機化合物討論会講演要旨集(Web)   59th   2017

  • 沖縄産Hyrtios属海綿由来新規アゼピノインドールアルカロイドhyrtinadine CおよびDの構造

    栗本慎一郎, 中村健太, 酒井香奈江, 五ノ井透, 久保田高明, 小林淳一

    日本薬学会年会要旨集(CD-ROM)   137th   2017

  • New polyketides from dinoflagellate Amphidinium sp.

    T. Kubota, T. Iwai, H. Sato, J. Kobayashi

    PLANTA MEDICA   82   2016.12

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    DOI: 10.1055/s-0036-1596659

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  • 沖縄産Stylissa属海綿から単離した新規環状ペプチドの構造

    栗本慎一郎, 中村健太, 久保田高明, 小林淳一

    天然薬物の開発と応用シンポジウム講演要旨集   21st   2016

  • 3P-272 Functional analysis of the cpaM in cyclopiazonic acid biosynthesis

    Kikuchi Tomoki, Koyama Akifumi, Iio shinichiro, Shinohara Yasutomo, Kubota Takaaki, Kobayashi Jyunichi, Koyama Yasuji, Tokuoka Masafumi, Shindo Hitoshi, Hosaka Masaru

    67   338 - 338   2015

  • New polyketides from marine dinoflagellate Amphidinium sp.

    T. Kubota, T. Iwai, J. Kobayashi

    PLANTA MEDICA   80 ( 10 )   765 - 765   2014.7

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  • 沖縄産Agelas属海綿から単離した新規ジテルペンアルカロイドagelasine O‐Uの構造

    IWAI TAKAHIRO, KUBOTA TAKAAKI, KATAKURA KEN, KOBAYASHI JUN'ICHI

    天然薬物の開発と応用シンポジウム講演要旨集   19th   110 - 112   2012.10

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  • 沖縄産ホヤEudistoma glaucus由来の新規β‐カルボリンアルカロイドEudistomidn H‐Kの構造

    久保田高明, 鈴木哲平, 小林淳一

    日本薬学会年会要旨集   132nd ( 2 )   194   2012.3

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  • 嫌われ者の藍藻に期待!(バイオミディア)

    久保田 高明

    生物工学会誌 : seibutsu-kogaku kaishi   89 ( 10 )   617 - 617   2011.10

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  • 嫌われ者の藍藻に期待!

    久保田高明

    生物工学会誌   89 ( 10 )   617 - 617   2011.10

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  • 沖縄産Plakortis属海綿由来の新規ポリケタイドUntenolide Aの構造

    久保田高明, 石黒悠一朗, 城始勇, 小林淳一

    日本薬学会年会要旨集   131st ( 2 )   230   2011.3

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  • 沖縄産海綿由来新規アルカロイドnakijinamine類の構造

    高橋洋平, 久保田高明, 小林淳一

    天然有機化合物討論会講演要旨集   52nd ( 52 )   661-666 - 666   2010.9

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    Language:Japanese   Publisher:Symposium on the chemistry of natural products  

    Aaptamine (6) was a characteristeic marine natural product possessing 1H^benzo[de][1,6]-naphthyridine ring, which was isolated from the Okinawan marine sponge Aaptos aaptos. Approximately 20 related alkaloids have been isolated from several species of marine sponges so far. A lot of interstint researches have been performed since the isolation of 6 in 1982 due to its unique structures and various biological activities. During our continuous search for structurally interesting metabolites from marine sponges, a new bromoindole alkaloid, 6-bromoconicamin (1), a hybrid compound of 1 and bisdemethylaaptamne (5), nakijinamine A (2), and its derivatives, nakijinamines B (3) and C (4), have been isolated from two collections of Suberites sp. (SS-1083 and SS-1084). Their structuers were elucidated from spectroscopic data and chemical conversions. 6-Bromoconicamin (1) is an indole alkaloid having bromine atom at C-6 in conicamin, which was isolated from the Mediterranean marine tunicate Aplidium conicum. Nakijinamine A (2) is the hybrid compound of 1 and bisdemethylaaptamine (5), while nakijinamines B (3) and C (4) are related alkaloids of 2. Although the elucidatio of the gross structure of 2 from its spectroscopic data was very difficult due to broadening signals in ^1H NMR spectrum of 2, the structure of 2 was able to be a ssigned from chemical conversions of 2. The structure of 3 was assigned as the debromo analog of 2 by the comparison of NMR data with 2. Although 4 had a lot of quaternary carbons and hetero atoms in its structure, its gross structure was elucidated from careful analysis of spectroscopic data and comparison of NMR data with known compounds. The confirmation of the structure of 4 and biological activities of 1-4 are in progress.

    DOI: 10.24496/tennenyuki.52.0_661

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  • アスヒカズラより単離した新規アルカロイドの構造

    石内勘一郎, 久保田高明, 林茂樹, 柴田敏郎, 小林淳一

    日本薬学会年会要旨集   130th ( 2 )   239   2010.3

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  • ナガサキオトギリより単離した新規benzophenone rhamnosideの構造

    田中直伸, 久保田高明, 柏田良樹, 高石喜久, 小林淳一

    日本薬学会年会要旨集   130th ( 2 )   233   2010.3

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  • 沖縄産海綿由来の新規ピリジニウムアルカロイドPlatisidine A〜Cの構造

    久保田高明, 石黒悠一朗, 山本淳, 小林淳一

    日本薬学会年会要旨集   130th ( 2 )   221   2010.3

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  • スギカズラ(Lycoposiumannotinum)より単離した新規アルカロイドの構造

    石内勘一郎, 児玉志保美, 久保田高明, 小林淳一, 林茂樹, 柴田敏郎

    日本生薬学会年会講演要旨集   56th   141   2009.9

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  • エゾオトギリHypericum yezoenseより単離したyezo’otogirin A‐Cの構造

    田中直伸, 格口ゆか, 石山玄明, 久保田高明, 小林淳一

    日本生薬学会年会講演要旨集   56th   256   2009.9

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  • 海綿由来の新規マンザミンアルカロイドzamamidine A〜Cの構造と生物活性

    高橋洋平, 山田美香, 久保田高明, 石山亜紀, 乙黒一彦, 山田陽城, 大村智, 小林淳一

    天然有機化合物討論会講演要旨集   51st ( 51 )   581-586 - 586   2009.9

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    Manzamine alkdloids are well known to be a group of marine natural products, which have a β-carboline moiety and a unique heterocyclic ring system. Since manzamine A had been isolated from a marine sponge Haliclona sp. in 1986, approximately 100 manzamine alkdloids containing biogenetic precursors have been idolated so far. A great number of studies on them, such as isolation and structural analysis, biosynthesis, and total synthesis, have been actively performed due to their intriguing structures and intersting biological activities. We have also isolated s seris of manzamine alkaloids from several genera and their structures have been elucidated by means of NMR spectra, chemical correlations, X-ray crystallography, and CD spectra. During our continuous search for structurally interesting metabolites from marine sponges, new manzamine alkdloids, zamamidines A-C (1-3), have been isolated, and their structures were elucidated by spectroscopic data. 1-3 are new manzamine alkdloids possessing a second β-carboline ring via an ethylene chain at N-2 of manzamine H, 1,2,3,4-tetrahydromanzamine B, and manzamine D, respectively. Since no manzamine alkdloids possessing any side chain at N-2 other than a methyl group have been reported to date, 1〜3 are the first examples of it. Zamamidines A-C (1-3) showed inhibitory activities against Plasmodium falciparum (Kl strain) and Tripanosoma brucei brucei (GUTat 3.1) in vitro.

    DOI: 10.24496/tennenyuki.51.0_581

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  • アスヒカズラ(Lycopodium complanatum)由来新規アルカロイドの構造

    石内勘一郎, 久保田高明, 林茂樹, 柴田敏郎, 小林淳一

    天然有機化合物討論会講演要旨集   51st ( 51 )   19-24 - 24   2009.9

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    Club moss (Lycopodiaceae) is known to be a rich source of Lycopodium alkaloids possessing unique heterocyclic ring systems such as C_<16>N, C_<16>N_2, and C_<27>N_3, which have attracted great interest from biogenetic, synthetic, and biological points of view. In our continuing efforts to find new Lycopodium alkaloids, lycopladine H (1), lyconadins C-E (2-4), lycoplaidines F-G (5-6), and complanadine E (7) were isolated from Lycopodium domplanatum. The structures for 1-7 were elucidated on the basis of spectral data. Lycopladine H (1) is an unprecedented C_<16>N-type Lycopodium alkaloid possessing a novel fused-tetracyclic ring system consisting of an azocane ring fused to a [2,2,2,]-bicyclooctane ring and 3-piperidinone ring, Lyconadin C (2) is a new tetracyclic Lycopodium alkaloid consisting of cyclohexane, cycloheptane, pyperidine, and pyridone rings. Lyconadin C (2) might be a biosynthetic precursor of lyconadin A. Lyconadins D (3) and E (4) are the first fastigiatine-type alkaloids isolated from Lycopodium complanatum. Lycopladine F (5) is a rare C_<16>N_2-type Lycopodium alkaloid possessing an amino acid residue (C_4N), while lycopladine G (6) is a 17-keto and 20-methylester form of lycopladine F (5). Complanadine E (7) is a new dimeric Lycopodium alkaloid consisting of two C_<16>N_2-type skeletons, which corresponds to 1,2,3,4,5,N-1-hexahydro complanadine A.

    DOI: 10.24496/tennenyuki.51.0_19

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  • Corrigendum to "Zamamidine C, 3,4-dihydro-6-hydroxy-10,11-epoxymanzamine A, and 3,4-dihydromanzamine J N-oxide, new manzamine alkaloids from sponge Amphimedon sp." [Tetrahedron 65 (2009) 2313-2317] (DOI:10.1016/j.tet.2009.01.032)

    Mika Yamada, Yohei Takahashi, Takaaki Kubota, Jane Fromont, Aki Ishiyama, Kazuhiko Otoguro, Haruki Yamada, Satoshi Omura, Jun'ichi Kobayashi

    Tetrahedron   65 ( 31 )   6263 - 6263   2009.8

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    DOI: 10.1016/j.tet.2009.05.081

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  • 渦鞭毛藻由来マクロリド・Amphidinolactone Aの全合成による立体化学の解明

    萩行正博, 石山玄明, 高橋洋平, 久保田高明, 小林淳一

    次世代を担う有機化学シンポジウム講演要旨集   7th   38-39   2009.5

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  • 沖縄産海綿由来の新規ブロモチロシンアルカロイドTyrokeradine AおよびBの構造

    久保田高明, 向井裕也, 小林淳一

    日本薬学会年会要旨集   129th ( 2 )   179   2009.3

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  • 渦鞭毛藻由来マクロリド・Amphidinolactone Aの全合成と立体化学の解明

    萩行正博, 石山玄明, 高橋洋平, 久保田高明, 小林淳一

    日本薬学会年会要旨集   129th ( 2 )   95   2009.3

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  • アスヒカズラより単離した新規リコポジウムアルカロイドの構造

    石内勘一郎, 久保田高明, 柴田敏郎, 小林淳一

    日本薬学会年会要旨集   129th ( 2 )   97   2009.3

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  • ビヨウヤナキより単離した新規xanthone誘導体の構造

    田中直伸, 大豆村拓自, 久保田高明, 今林潔, 柏田良樹, 高石喜久, 小林淳一

    日本薬学会年会要旨集   129th ( 2 )   172   2009.3

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  • アカネ科植物由来の新規モノテルペンインドールアルカロイド・Naucleamide Fの構造

    石山玄明, 格口ゆか, 高橋洋平, 久保田高明, 小林淳一

    日本薬学会年会要旨集   129th ( 2 )   179   2009.3

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  • 沖縄産Agelas属海綿より単離した新規ブロモピロールアルカロイドの構造

    荒木敦, 久保田高明, 三上襄, 小林淳一

    天然薬物の開発と応用シンポジウム講演要旨集   17th   79-80   2008.11

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  • 沖縄産海綿より単離したnakijiquinone/metachromin類の構造と生物活性

    高橋洋平, 久保田高明, 三上襄, 小林淳一

    天然有機化合物討論会講演要旨集   50th   59-64   2008.9

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  • 6 Nakijiquinones and Metachromins, New Sesquiterpenoid Quinones from Okinawan Marine Sponges : Isolation, Structure Elucidation, and Biological Activities(Oral Presentation)

    Takahashi Yohei, Kubota Takaaki, Mikami Yuzuru, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   0 ( 50 )   59 - 64   2008.9

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    Sesquiterpenoid quinines and hydroquinones are representative marine natural products with unique structures and interesting biological activities. In our continuous search for bioactive compounds having unique structures from Okinawan marine sponges, we have isolated new sesquiterpenoid quinones, nakijiquinones E〜I (1〜5) and metachromins L-Q (6〜11), from three collections of Okinawan marine sponges. The structures of 1〜5 were elucidated on the basis of 2D NMR data, while those of 6〜11 were established by chemical correlations. Furthermore, biological activities for 1〜11 and synthetic metac...

    DOI: 10.24496/tennenyuki.50.0_59

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  • P-33 Nagelamides K, M, and N, Novel Bromopyrrole Alkaloids from Okinawan Marine Sponge Agelas sp(Poster Presentation)

    Araki Atsushi, Yasuda Tetsuro, Kubota Takaaki, Mikami Yuzuru, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   0 ( 50 )   361 - 366   2008.9

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    Bromopyrrole alkaloids are known to be one of the most common metabolites contained in marine sponges. During our search for bioactive substances from marine organisms, we have isolated bromopyrrole alkaloids with unique cyclic skeletons from sponges of the genus Agelas or Hymeniacidon. Recently, three new bromopyrrole alkaloids, nagelamides K, M, and N (1-3), have been isolated from an Okinawan marine sponge Agelas sp. (SS-1134). The structures and relative stereochemistry of 1〜3 were elucidated on the basis of spectroscopic data. Nagelamide K (1) is a new dimeric bromopyrrole alkaloid pos...

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  • ナガサキオトギリ由来の新規フロログルシノール誘導体petiolin Dの構造

    田中直伸, 久保田高明, 石山玄明, 小林淳一, 柏田良樹, 高石喜久, 伊藤淳二, 三上襄, 城始勇

    日本生薬学会年会講演要旨集   55th   188   2008.9

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  • 沖縄産海綿由来の新規ブロモピロールアルカロイドの構造

    荒木敦, 安田鉄郎, 久保田高明, 三上襄, 小林淳一

    天然有機化合物討論会講演要旨集   50th ( 50 )   361-366 - 366   2008.9

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    Bromopyrrole alkaloids are known to be one of the most common metabolites contained in marine sponges. During our search for bioactive substances from marine organisms, we have isolated bromopyrrole alkaloids with unique cyclic skeletons from sponges of the genus Agelas or Hymeniacidon. Recently, three new bromopyrrole alkaloids, nagelamides K, M, and N (1-3), have been isolated from an Okinawan marine sponge Agelas sp. (SS-1134). The structures and relative stereochemistry of 1〜3 were elucidated on the basis of spectroscopic data. Nagelamide K (1) is a new dimeric bromopyrrole alkaloid possessing a rare piperidinoiminoimidazolone ring with an aminoimidazole ring and a taurine unit. Nagelamide M (2) is a novel bromopyrrole alkaloid possessing an 2-amino-octahydropyrrolo[2,3-d]imidazol ring with a taurine unit, while nagelamide N (3) is a new bromopyrrole alkaloid consisting of an 2-amino-tetrahydroimidazol-4-one ring with a taurine unit and 3-(dibromopyrrole-2-carboxamido)propanoic acid moiety. Nagelamides K, M, and N (1-3) showed modest antimicrobial activity.

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  • シマサルスベリより単離した新規Lythraceaeアルカロイドの構造

    久保田高明, 渡辺梢, 小林淳一, 新里孝和, 伊藤淳二, 三上襄

    日本生薬学会年会講演要旨集   55th   219   2008.9

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  • ナガサキオトギリより単離した新規フロログルシノール誘導体petiolin A‐Cの構造

    田中直伸, 久保田高明, 荒木敦, 柏田良樹, 高石喜久, 三上襄, 小林淳一

    日本薬学会年会要旨集   128th ( 2 )   11   2008.3

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  • 沖縄産海綿Spongia sp.由来の新規テルペノイドMetachromin R〜Tの構造

    山田美香, 高橋洋平, 久保田高明, 小林淳一

    日本薬学会年会要旨集   128th ( 2 )   11   2008.3

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  • ユズリハ科植物由来の新規アルカロイドCalyciphylline H〜Mの構造

    八幡弘子, 齊藤静夏, 久保田高明, 小原祐太郎, 中畑則道, 小林淳一

    日本薬学会年会要旨集   128th ( 2 )   12   2008.3

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  • 沖縄産海綿Amphimedon sp.由来の新規アルカロイドNakinadine Aの構造

    久保田高明, 西貴美, 佐々木琢磨, 小林淳一

    日本薬学会年会要旨集   128th ( 2 )   12   2008.3

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  • Multi Phenotypic Screeningによる生理活性物質の作用解析

    風見紗弥香, 風見紗弥香, 臼井健郎, 臼井健郎, 久保田高明, 小林淳一, 長田裕之, 長田裕之

    日本農芸化学会大会講演要旨集   2008   9   2008.3

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  • アスヒカズラより単離した新規アルカロイドの構造

    久保田高明, 八幡弘子, 石内勘一郎, 小林淳一

    日本生薬学会年会講演要旨集   54th   226   2007.9

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  • P-11 Calyciphyllines C〜G, Novel Daphniphyllum Alkaloids from Daphniphyllum calycinum

    Saito Shizuka, Kubota Takaaki, Fukushi Eri, Kawabata Jun, Zhang Huiping, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   0 ( 49 )   271 - 276   2007.8

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    Daphniphyllum alkaloids are a structually diverse group of natural products with unique fused-heterocyclic skeletons, which are elaborated by trees of the genus Daphniphyllum (Daphniphyllaceae). These unusual ring systems have been challenging targets for total synthesis as well as biosynthetic studies. We have isolated novel types of Daphniphyllum alkaloids from Daphniphyllum macropodum, D. humile, D. teijsmanni, and D. glaucescense. In our continuing search for structually unique and biogenetically interesting new alkaloids, calyciphyllines C-G (1-5) have been isolated from D. calycinum, ...

    DOI: 10.24496/tennenyuki.49.0_271

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  • ユズリハ科植物由来の新規アルカロイドcalyciphylline C〜Gの構造と生物活性

    齊藤静夏, 久保田高明, 福士江里, 川端潤, ZHANG Huiping, 小林淳一

    天然有機化合物討論会講演要旨集   49th ( 49 )   271-276 - 276   2007.8

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    Daphniphyllum alkaloids are a structually diverse group of natural products with unique fused-heterocyclic skeletons, which are elaborated by trees of the genus Daphniphyllum (Daphniphyllaceae). These unusual ring systems have been challenging targets for total synthesis as well as biosynthetic studies. We have isolated novel types of Daphniphyllum alkaloids from Daphniphyllum macropodum, D. humile, D. teijsmanni, and D. glaucescense. In our continuing search for structually unique and biogenetically interesting new alkaloids, calyciphyllines C-G (1-5) have been isolated from D. calycinum, and their structures and relative stereochemistry were elucidated on the basis of spectroscopic data. Calyciphylline C (1) is a novel Daphniphyllum alkaloid with an unprecedented fused-hexacyclic skeleton having an azetidine ring. Calyciphyllines D (2) and F (4) are novel alkaloids containing a unique fused-pentacyclic skeleton with a 8-azatricyclo[4.2.1.0.^<4,8>]nonane ring system. Calyciphylline E (3) is a new alkaloid with a fused-heptacyclic ring system, while calyciphylline G (5) is a novel alkaloid possessing an unprecedented fused-hexacyclic skeleton containg 5-azatricyclo[6.2.1.0]undecane ring system. Effects of these alkaloids on neurotrophic factor biosynthesis in 1321N1 human astrocytoma cells were examined by a semiquantitative RT-PCR method to find that the mRNA expressions for NGF were enhanced.

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  • ケミカルバイオロジー研究のフロンティア 創薬リードとしての分子標的天然薬物の探索

    小林淳一, 久保田高明

    現代化学   ( 436 )   21-26 - 26   2007.7

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  • 創薬リードとしての分子標的天然薬物の探索

    小林 淳一, 久保田 高明

    現代化学   0 ( 436 )   21 - 26   2007.7

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  • 渦鞭毛藻由来の新規amphidinolide関連化合物の構造

    高橋洋平, 久保田高明, 小林淳一

    次世代を担う有機化学シンポジウム講演要旨集   5th   6-7   2007.5

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  • 免疫抑制物質brasilicardin Aの標的分子同定

    臼井健郎, 臼井健郎, 南雲陽子, 南雲陽子, 渡邉愛, 久保田高明, 小林淳一, 長田裕之

    日本農芸化学会大会講演要旨集   2007   98   2007.3

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  • 1 Agesamides and Nagelamides, Novel Bromopyrrole Alkaloids from Sponge Agelas spp.

    Yasuda Tetsuro, Araki Atsushi, Tsuda Masashi, Kubota Takaaki, Fukushi Eri, Kawabata Jun, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   49 ( 0 )   1 - 6   2007

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    Diffusion-ordered NMR spectroscopy (DOSY) is a versatile and powerful NMR technique and a noninvasive analytical method for mixture analysis that does not require prior physical separation of the analysis. In our search for new metabolites from natural resources, DOSY was applied for constituent analysis of crude bromopyrrole fractions separated from an Okinawan marine sponge Agelas sp. (SS-1056) so that two new bromopyrrole alkaloids, agesamides A (1) and B (2), have been isolated. The structures and relative stereochemistry of 1 and 2 were elucidated fromspectroscopic data. Furthermore, two new bromopyrrole alkaloids, nagelamides J (3) and K (4), have been isolated from another Okinawan marine sponge Agelas sp. (SS-1077), and the structures and relative stereochemistries were elucidated from spectroscopic data. Nagelamide J (3) is the first bromopyrrole alkaloid possessing a cyclopentane ring fused to an amino imidazole ring and nagelamide K (4) is a unique dimeric bromopyrrole alkaloid containing an ester linkage. Nagelamide J (3) exhibited antimicrobial activity against Staphylococcus aureus (MIC, 8.35μg/ml) and antifungal activity against Cryptococcus neoformans (MIC, 16.7μg/ml), while nagelamide K (4) exhibited antimicrobial activity against Micrococcus luteus (MIC, 16.7μg/ml).

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  • 1 Agesamides and Nagelamides, Novel Bromopyrrole Alkaloids from Sponge Agelas spp.

    Yasuda Tetsuro, Araki Atsushi, Tsuda Masashi, Kubota Takaaki, Fukushi Eri, Kawabata Jun, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   49 ( 0 )   1 - 6   2007

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    Diffusion-ordered NMR spectroscopy (DOSY) is a versatile and powerful NMR technique and a noninvasive analytical method for mixture analysis that does not require prior physical separation of the analysis. In our search for new metabolites from natural resources, DOSY was applied for constituent analysis of crude bromopyrrole fractions separated from an Okinawan marine sponge Agelas sp. (SS-1056) so that two new bromopyrrole alkaloids, agesamides A (1) and B (2), have been isolated. The structures and relative stereochemistry of 1 and 2 were elucidated fromspectroscopic data. Furthermore, two new bromopyrrole alkaloids, nagelamides J (3) and K (4), have been isolated from another Okinawan marine sponge Agelas sp. (SS-1077), and the structures and relative stereochemistries were elucidated from spectroscopic data. Nagelamide J (3) is the first bromopyrrole alkaloid possessing a cyclopentane ring fused to an amino imidazole ring and nagelamide K (4) is a unique dimeric bromopyrrole alkaloid containing an ester linkage. Nagelamide J (3) exhibited antimicrobial activity against Staphylococcus aureus (MIC, 8.35μg/ml) and antifungal activity against Cryptococcus neoformans (MIC, 16.7μg/ml), while nagelamide K (4) exhibited antimicrobial activity against Micrococcus luteus (MIC, 16.7μg/ml).

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  • STRUCTURES AND PLAUSIBLE BIOGENETIC PATHWAY FOR NOVEL ALKALOIDS FROM DAPHNIPHYLLUM SPECIES

    MATSUNO YOSUKE, OKAMOTO MARIKO, ZAIMA KAZUMASA, KUBOTA TAKAAKI, KOBAYASHI JUN'ICHI, SHINZATO TAKAKAZU, MORITA HIROSHI

    薬学雑誌   126 ( Suppl.5 )   100-103 - 103   2006.11

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  • ABSOLUTE STEREOCHEMISTRY AND MOLECULAR TARGET OF ANTITUMOR MACROLIDES, IEJIMALIDES

    KUBOTA TAKAAKI, NOZAWA KOHEI, TSUDA MASASHI, ISHIYAMA HARUAKI, KAZAMI SAYAKA, USUI TAKEO, OSADA HIROYUKI, KOBAYASHI JUN'ICHI

    薬学雑誌   126 ( Suppl.5 )   222-225   2006.11

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  • アスヒカズラLycopodium complanatum由来の新規アルカロイドの構造と生物活性

    石内勘一郎, 久保田高明, 森田博史, 星野智洋, 小原祐太郎, 中畑則道, 小林淳一

    天然有機化合物討論会講演要旨集   48th ( 48 )   493-498 - 498   2006.9

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    Club moss (Lycopodiaceae) is known to be a rich source of Lycopodium alkaloids posessing unique heterocyclic ring systems such as C_<16>N, C_<16>N_2, and C_<27>N_3, which have attracted great interest from biogenetic, synthetic, and biological points of view. In our continuing efforts to find new Lycopodium alkaloids, lycopladines A-D (1-4), lyconadin B (5), and complanadines C (6), D (7) were isolated from the club moss Lycopodium complanatum. The structures for 1-7 were elucidated on the basis of spectral data. Lycopladine A (1) obtained as colorless amourphous solid, showed the pseudomolecular ion peak at m/z 260 (M+H)^+ in the ESIMS, and the molecular formula, C_<16>H_<21>NO_2, was established by HRESIMS [m/z 260.1653, (M+H)^+, △+0.2mmu]. The gross structure of 1 was elucidated on the basis of 2D NMR data. The relative stereochemistry of 1 was elucidated from NOESY data. Lycopladine A (1) possesses an unprecedented skeleton different from known C_<16>N-type Lycopodium alkaloids. The stuructures of lycopladines B-D (2-4) were elucidated on the basis of spectroscopic data and modified Mosher's method. Lycopladine B (2) was 5-hydroxyl, △_<8,15>, △_<13,14>, and 17-methyl ester form of fawcettidane skeleton. Lycopladine C (3) was assigned as 5-O-acetyl form of 2. Lycopladine D (4) had fawcettidane skeleton with hydroxyl group at C-5 and lactone ring (C-13〜C-16). The absolute stereochemistry of 2 and 4 were elucidated by modified Mosher's method. The absolute configuration at C-5 of 2 and 4 were assigned to be S and R, respectively. Lyconadin B (5) was assigned as dihydro form of lyconadin A. Complanadines C (6) and D (7) were obtained as colorless amorphous solids. The structures and relative stereochmistry of 6 and 7 were elucidated on the basis of spectroscopic data. Complanadine C (6) was assigned as the dimer of 9-keto, △_<10,11> form of lycopodine and △_<9,10> form of lycopodine. The dimer of lycopodane skeleton has not been reported previously. Complanadine D (7) was tetrahydro form of complanadine A. A plausible biogenetic path of lyconadin A (8) was proposed on the basis of structure of lycopladine A (1). Biogenetically, lyconadines A (8) and B (5) might be derived from L-lysine via pelletierine, phlegmarane skeleton, and an intermediate X from which lycopladine A (1) might be provided. Effects of lycopladines A-D (1-4), and lyconadins A (8) and B (5) on neurotrophic factor biosynthesis in 1321N1 human astrocytoma cells were examined. The mRNA expressions of NGF in 1321N1 cells were examined by a semiquantitative RT-PCR method. The mRNA expressions for NGF were enhanced by lyconadins A (8) and B (5).

    DOI: 10.24496/tennenyuki.48.0_493

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  • P-16 Structures and Biological Activity of New Lycopodium Alkaloids from Lycopodium complanatum

    Ishiuchi Kan'ichiro, Kubota Takaaki, Morita Hiroshi, Hoshino Tomohiro, Obara Yutaro, Nakahata Norimichi, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   0 ( 48 )   493 - 498   2006.9

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    Club moss (Lycopodiaceae) is known to be a rich source of Lycopodium alkaloids posessing unique heterocyclic ring systems such as C_&lt;16&gt;N, C_&lt;16&gt;N_2, and C_&lt;27&gt;N_3, which have attracted great interest from biogenetic, synthetic, and biological points of view. In our continuing efforts to find new Lycopodium alkaloids, lycopladines A-D (1-4), lyconadin B (5), and complanadines C (6), D (7) were isolated from the club moss Lycopodium complanatum. The structures for 1-7 were elucidated on the basis of spectral data. Lycopladine A (1) obtained as colorless amourphous solid, showed the pseudomol...

    DOI: 10.24496/tennenyuki.48.0_493

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  • ヒメユズリハ(Daphniphyllum teijsmannii)より単離した新規アルカロイドDaphtenidine A‐Dの構造

    松野陽介, 松野陽介, 久保田高明, 森田博史, 新里孝和, 関口光広, 小林淳一

    日本生薬学会年会講演要旨集   53rd   152 - 152   2006.9

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  • アスヒカズラLycopodium complanatum由来の新規アルカロイドの構造と生物活性

    石内勘一郎, 久保田高明, 小林淳一, 森田博史, 星野智洋, 小原祐太郎, 中畑則道

    日本生薬学会年会講演要旨集   53rd   157   2006.9

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  • 放線菌由来細胞毒性物質・ブラシリカルジン類の構造と活性

    小林淳一, 久保田高明

    日本癌学会学術総会記事   65th   466-467   2006.8

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  • リコポジウムアルカロイドの構造の多様性と生物活性

    石内勘一郎, 久保田高明, 小林淳一, 森田博史

    万有生命科学振興国際交流財団札幌シンポジウム   18th   42   2006.7

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  • Promising V-ATPase Inhibitors as Drugs for Treatment of Osteoporosis and Tumor.

    KOBAYASHI JUN'ICHI, KUBOTA TAKAAKI

    化学   61 ( 6 )   68-69   2006.6

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  • 沖縄産海綿Cribrochalina sp.より単離した新規ピリジンアルカロイドPyrinadine Aの構造

    久保田高明, 仮屋佑子, 小林淳一

    日本薬学会年会要旨集   126th ( 4 )   86   2006.3

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  • Iejimalidesの標的分子の同定

    風見紗弥香, 臼井健郎, 室井誠, 久保田高明, 小林淳一, 長田裕之

    日本農芸化学会大会講演要旨集   2006   11   2006.3

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  • 沖縄産ホヤ由来マクロリド・イエジマリド類の構造と生物活性 (第16回 天然薬物の開発と応用シンポジウム講演要旨集)

    久保田 高明, 野沢 耕平, 津田 正史

    薬学雑誌   126 ( 0 )   222 - 225   2006

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  • 海洋渦鞭毛藻由来の新規ポリケチドの探索

    久保田高明, 佐久間裕介, 新保和高, 津田正史, 小林淳一

    マリンバイオテクノロジー学会大会講演要旨集   8th   109   2005.5

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  • 27 Structure Elucidation and Biosynthetic Studies of Amphezonol A, a Novel Polyhydroxyl Metabolite from Symbiotic Marine Microalga

    Kubota Takaaki, Sakuma Yusuke, Shimbo Kazutaka, Tsuda Masashi, Uozumi Yasuhiro, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   47 ( 0 )   151 - 156   2005

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    Amphezonol A (1), a novel polyhydroxyl compound, was isolated from a marine dinoflagellate Amphidinium sp. (Y-72), and the structure was elucidated on the basis of 2D NMR data including HSQC-TOCSY and INADEQUATE spectra (920MHz) using the ^<13>C-enriched sample. Amphezonol A (1), C_<62>H_<114>O_<24>, was the first member of a new class of polyketide natural products consisting of a C_<60>-linear aliphatic chain with twenty-one hydroxyl groups, and two tetrahydropyran and a tetrahydrofuran rings. Cloning of polyketide synthase (PKS) gene from a dinoflagellate Amphidinium sp. was attempted and PKS gene fragments were obtained by PCR amplification from degenerated primer sets designed on the basis of the conserved amino acid sequences in known type I PKSs. The PCR analysis, using primer sets designed from these PKS gene fragments, revealed that these DNA sequences exist only in the dinoflagellates producing polyketides.

    DOI: 10.24496/tennenyuki.47.0_151

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  • 27 Structure Elucidation and Biosynthetic Studies of Amphezonol A, a Novel Polyhydroxyl Metabolite from Symbiotic Marine Microalga

    Kubota Takaaki, Sakuma Yusuke, Shimbo Kazutaka, Tsuda Masashi, Uozumi Yasuhiro, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   47 ( 0 )   151 - 156   2005

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    Amphezonol A (1), a novel polyhydroxyl compound, was isolated from a marine dinoflagellate Amphidinium sp. (Y-72), and the structure was elucidated on the basis of 2D NMR data including HSQC-TOCSY and INADEQUATE spectra (920MHz) using the ^<13>C-enriched sample. Amphezonol A (1), C_<62>H_<114>O_<24>, was the first member of a new class of polyketide natural products consisting of a C_<60>-linear aliphatic chain with twenty-one hydroxyl groups, and two tetrahydropyran and a tetrahydrofuran rings. Cloning of polyketide synthase (PKS) gene from a dinoflagellate Amphidinium sp. was attempted and PKS gene fragments were obtained by PCR amplification from degenerated primer sets designed on the basis of the conserved amino acid sequences in known type I PKSs. The PCR analysis, using primer sets designed from these PKS gene fragments, revealed that these DNA sequences exist only in the dinoflagellates producing polyketides.

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  • Absolute Stereochemistry of Amphidinolide E.

    KUBOTA TAKAAKI, TSUDA MASASHI, KOBAYASHI JUN'ICHI

    日本化学会講演予稿集   81st ( 2 )   707   2002.3

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  • Studies on biosynthesis of amphidinolides.

    TSUDA MASASHI, KUBOTA TAKAAKI, SHIMBO KAZUTAKA, HORIGUCHI TAKEO, KATSUMATA KAZUHITO, KOBAYASHI JUN'ICHI

    日本化学会講演予稿集   80th   3   2001.9

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  • 沖縄産海綿Suberea sp.より単離した新規ブロモチロシンアルカロイドMa′edamine AとBの構造

    久保田高明, 津田正史, 平野敬子, 渡部賢二, 小林淳一

    日本薬学会年会要旨集   121年会 ( 2 )   119 - 119   2001.3

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  • 17 Stereochemistry of Amphidinolides C and T1〜T5

    Kubota Takaaki, Tsuda Masashi, Endo Tetsuya, Shiro Motoo, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   43 ( 0 )   97 - 102   2001

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    Amphidinolide C (1) is a unique 25-membered macrolide isolated from a marine dinoflagellate Amphidinium sp. (strain Y-5). The gross structure of 1 has been elucidated by 2D-NMR data, whereas the stereochemistry remains undefined. During our search for bioactive metabolites from marine dinoflagellates, relatively large amounts of 1 have been recently isolated from two strains (Y-56 and Y-71) of the genus Amphidinium, which allowed us to investigate the stereochemistry of 1 Absolute configurations at C-12, C-13, C-20, C-23, C-24, and C-29 of amphidinolide C (1) were assigned by combination of NMR analyses including J-based configuration analysis and Mosher's method, while absolute configurations at C-7 and C-8 of 1 were assigned by application of Mosher's method for erythro glycol and comparison of ^1H-NMR data of natural specimen with those of synthetic C-1-C-10 segments. Absolute configurations at C-3, C-4, C-6, and C-16 of 1 were elucidated by comparison of NMR data of degradation products of 1 with synthetic C-1-C-7 and C-16-C-18 segments. On the other hand, five new 19-membered macrolides amphidinolides T1-T5 (2-6) have been isolated from the Y-56 and Y-71 strains of the genus Amphdinium. The gross structures were elucidated by 2D-NMR analyses. Absolute configurations at C-2, C-13, C-14, and C-18 of amphidinolide T1 (2) were assigned on the basis of NMR data of the MTPA esters of 2 and those of degradation products of 2, while absolute configurations at C-7, C-8, and C-10 of 2 were elucidated by comparison of ^1H-NMR data of C-1-C-12 segment with those of synthetic model compounds for tetrahydrofuran portion. The absolute stereochemistry of amphidinolides T2-T5 (3-6) were also elucidated by similar methods. The stereostructure of 2 was also confirmed by a single crystal X-ray diffraction analysis.

    DOI: 10.24496/tennenyuki.43.0_97

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  • 17 Stereochemistry of Amphidinolides C and T1〜T5

    Kubota Takaaki, Tsuda Masashi, Endo Tetsuya, Shiro Motoo, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   43 ( 0 )   97 - 102   2001

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    Amphidinolide C (1) is a unique 25-membered macrolide isolated from a marine dinoflagellate Amphidinium sp. (strain Y-5). The gross structure of 1 has been elucidated by 2D-NMR data, whereas the stereochemistry remains undefined. During our search for bioactive metabolites from marine dinoflagellates, relatively large amounts of 1 have been recently isolated from two strains (Y-56 and Y-71) of the genus Amphidinium, which allowed us to investigate the stereochemistry of 1 Absolute configurations at C-12, C-13, C-20, C-23, C-24, and C-29 of amphidinolide C (1) were assigned by combination of NMR analyses including J-based configuration analysis and Mosher's method, while absolute configurations at C-7 and C-8 of 1 were assigned by application of Mosher's method for erythro glycol and comparison of ^1H-NMR data of natural specimen with those of synthetic C-1-C-10 segments. Absolute configurations at C-3, C-4, C-6, and C-16 of 1 were elucidated by comparison of NMR data of degradation products of 1 with synthetic C-1-C-7 and C-16-C-18 segments. On the other hand, five new 19-membered macrolides amphidinolides T1-T5 (2-6) have been isolated from the Y-56 and Y-71 strains of the genus Amphdinium. The gross structures were elucidated by 2D-NMR analyses. Absolute configurations at C-2, C-13, C-14, and C-18 of amphidinolide T1 (2) were assigned on the basis of NMR data of the MTPA esters of 2 and those of degradation products of 2, while absolute configurations at C-7, C-8, and C-10 of 2 were elucidated by comparison of ^1H-NMR data of C-1-C-12 segment with those of synthetic model compounds for tetrahydrofuran portion. The absolute stereochemistry of amphidinolides T2-T5 (3-6) were also elucidated by similar methods. The stereostructure of 2 was also confirmed by a single crystal X-ray diffraction analysis.

    DOI: 10.24496/tennenyuki.43.0_97

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  • Two New Cyclic Depsipeptides from Okinawan Marine Sponge Theonella sp.

    SHIMBO KAZUTAKA, KUBOTA TAKAAKI, TSUDA MASASHI, KOBAYASHI JUN'ICHI

    日本化学会講演予稿集   78th ( 2 )   849   2000.3

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  • Amphidinolide V, Novel 14-Membered Macrolide from Marine Dinoflagellate Amphidinium sp.

    KUBOTA TAKAAKI, TSUDA MASASHI, KOBAYASHI JUN'ICHI

    日本化学会講演予稿集   78th ( 2 )   884   2000.3

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  • 100(P48) Colopsinols A and B, Novel Polyhydroxyl Metabolites from Marine Dinoflagellate Amphidinium sp.

    Kubota Takaaki, Tsuda Masashi, Takahashi Miho, Ishibashi Masami, Kobayashi Jun'ichi, Naoki Hideo

    Symposium on the Chemistry of Natural Products, symposium papers   41 ( 0 )   595 - 600   1999

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    Marine dinoflagellates of the genus Amphidinium have been recognized as a rich source of novel bioactive substances with unique structures. We previously isolated a series of cytotoxic macrolides, designated amphidinolides, possessing unique structural features from several strains of the dinoflagellates Amphidinium sp., among which the strain Y-5 was the richest source of the amphidinolides. Further search for metabolites from the strain Y-5, which was a symbiont of Okinawan marine acoel flatworm Amphiscolops sp., resulted in the isolation of two novel polyhydoroxyl compounds, colopsinols A (1) and B (2), belonging to a new class of polyketide metabolites. The structures of 1 and 2 were elucidated on the basis of extensive NMR techniques including a newly developed 2D NMR experiments such as CH_2-selected editing HSQC (E-HSQC) as well as FABMS/MS data. Colopsinols A (1) and B (2) are new class of polyketide natural products consisting of C_<56> and C_<53>-liner carbon chains, respectively, possessing a gentiobioside (β-D-glucopyranosyl-(1-6)-β-D-glucopyranoside) moiety and a sulfate ester. From this strain (Y-5), 13 cytotoxic macrolides, amphidinolides A-D, J, K, and M-S, have been isolated so far. Biosynthetically it is interesting that quite different type of polyketides such as colopsinols and amphidinolides are produced from the same dinoflagellate. Colopsinol A (1) showed inhibitory activity against DNA polymerase α and β with IC_<50> values of 13 and 7μM, respectively.

    DOI: 10.24496/tennenyuki.41.0_595

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  • 100(P48) Colopsinols A and B, Novel Polyhydroxyl Metabolites from Marine Dinoflagellate Amphidinium sp.

    Kubota Takaaki, Tsuda Masashi, Takahashi Miho, Ishibashi Masami, Kobayashi Jun'ichi, Naoki Hideo

    Symposium on the Chemistry of Natural Products, symposium papers   41 ( 0 )   595 - 600   1999

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    Marine dinoflagellates of the genus Amphidinium have been recognized as a rich source of novel bioactive substances with unique structures. We previously isolated a series of cytotoxic macrolides, designated amphidinolides, possessing unique structural features from several strains of the dinoflagellates Amphidinium sp., among which the strain Y-5 was the richest source of the amphidinolides. Further search for metabolites from the strain Y-5, which was a symbiont of Okinawan marine acoel flatworm Amphiscolops sp., resulted in the isolation of two novel polyhydoroxyl compounds, colopsinols A (1) and B (2), belonging to a new class of polyketide metabolites. The structures of 1 and 2 were elucidated on the basis of extensive NMR techniques including a newly developed 2D NMR experiments such as CH_2-selected editing HSQC (E-HSQC) as well as FABMS/MS data. Colopsinols A (1) and B (2) are new class of polyketide natural products consisting of C_<56> and C_<53>-liner carbon chains, respectively, possessing a gentiobioside (β-D-glucopyranosyl-(1-6)-β-D-glucopyranoside) moiety and a sulfate ester. From this strain (Y-5), 13 cytotoxic macrolides, amphidinolides A-D, J, K, and M-S, have been isolated so far. Biosynthetically it is interesting that quite different type of polyketides such as colopsinols and amphidinolides are produced from the same dinoflagellate. Colopsinol A (1) showed inhibitory activity against DNA polymerase α and β with IC_<50> values of 13 and 7μM, respectively.

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  • Structure of new polyol compound Luteophanol B isolated from Gonyaulax Amphidinium species.

    KUBOTA TAKAAKI, TSUDA MASAFUMI, DOI YUKIKO, NAKAMICHI HIROKO, ISHIBASHI MASAMI, KOBAYASHI JUN'ICHI

    日本薬学会年会要旨集   118th ( 2 )   108   1998.3

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  • 80(P63) Luteophanols B and C, New Polyhydroxyl Compounds from Marine Dinoflagellate

    Kubota Takaaki, Tsuda Masashi, Doi Yukiko, Takahashi Ayako, Nakamichi Hiroko, Ishibashi Masami, Fukushi Eri, Kawabata Jun, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   40 ( 0 )   473 - 478   1998

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    During our continuing search for structurally unique secondary metabolites from marine dinoflagellates, we previously isolated a series of cytotoxic macrolides, amphidinolides, from dinoflagellates Amphidinium sp. Recently we investigated another strain of Amphidinium sp. (strain number Y-52), which was isolated from the inside cells of the Okinawan marine acoel flatworm Pseudaphanostoma luteocoloris, and isolated two new polyhydroxyl compounds, luteophanols B (1) and C (2), both consisting of a C_<64>-linear aliphatic chain. The structure elucidation of 1 and 2 were elucidated on the basis of chemical degradation and newly developed 2D NMR experiments, E-HSQC and E-HSQC-TOCSY. E-HSQC and E-HSQC-TOCSY are very useful techniques for structure elucidations of complex natural products possessing many aliphatic methine and methylene carbons such as luteophanols B (1) and C (2). CH_2-selected E-HSQC-TOCSY^6 experiments seem to be suitable to assign very closely resonated carbon signals, since this method affords the high resolution in F_1 axis by limiting the F_1 spectral width, in which sp^2 methylene carbons are resonated.

    DOI: 10.24496/tennenyuki.40.0_473

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  • 80(P63) Luteophanols B and C, New Polyhydroxyl Compounds from Marine Dinoflagellate

    Kubota Takaaki, Tsuda Masashi, Doi Yukiko, Takahashi Ayako, Nakamichi Hiroko, Ishibashi Masami, Fukushi Eri, Kawabata Jun, Kobayashi Jun'ichi

    Symposium on the Chemistry of Natural Products, symposium papers   40 ( 0 )   473 - 478   1998

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    During our continuing search for structurally unique secondary metabolites from marine dinoflagellates, we previously isolated a series of cytotoxic macrolides, amphidinolides, from dinoflagellates Amphidinium sp. Recently we investigated another strain of Amphidinium sp. (strain number Y-52), which was isolated from the inside cells of the Okinawan marine acoel flatworm Pseudaphanostoma luteocoloris, and isolated two new polyhydroxyl compounds, luteophanols B (1) and C (2), both consisting of a C_<64>-linear aliphatic chain. The structure elucidation of 1 and 2 were elucidated on the basis of chemical degradation and newly developed 2D NMR experiments, E-HSQC and E-HSQC-TOCSY. E-HSQC and E-HSQC-TOCSY are very useful techniques for structure elucidations of complex natural products possessing many aliphatic methine and methylene carbons such as luteophanols B (1) and C (2). CH_2-selected E-HSQC-TOCSY^6 experiments seem to be suitable to assign very closely resonated carbon signals, since this method affords the high resolution in F_1 axis by limiting the F_1 spectral width, in which sp^2 methylene carbons are resonated.

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Industrial property rights

  • 渦鞭毛藻由来のポリケチド合成酵素遺伝子

    久保田 高明, 小林 淳一

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    Applicant:国立大学法人 北海道大学

    Application no:特願2005-186086  Date applied:2005.6.27

    Announcement no:特開2007-000104  Date announced:2007.1.11

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Awards

  • 学術貢献賞

    2016   日本生薬学会  

    久保田 高明

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Research Projects

  • Revealing symbiotic mechanisms from useful metabolites of microorganisms in corals

    Grant number:23H02132  2023.04 - 2026.03

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

    將口 栄一, 濱田 麻友子, 久保田 高明, 竹内 猛

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    Grant amount:\18720000 ( Direct expense: \14400000 、 Indirect expense:\4320000 )

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  • 海産天然物をシーズとした核内受容体PXRアンタゴニストの開発

    Grant number:20K07116  2020.04 - 2023.03

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    久保田 高明

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    Grant amount:\4290000 ( Direct expense: \3300000 、 Indirect expense:\990000 )

    薬物代謝は異物を体外に排出する重要な解毒機構であるが、一方で異物とみなした薬物の薬効を減弱させてしまう。核内受容体 Pregnane X Receptor(PXR)は、薬物代謝酵素や薬物トランスポーターの発現を誘導し、薬物代謝を亢進させることにより様々な薬物の薬効を減弱させる。PXRの機能を阻害すれば薬物の薬効減弱を防ぐことができるが、選択的な阻害剤は合成化合物のSPA70のみであるため、新しいタイプの阻害剤の開発が求められている。本研究では、PXR阻害剤の探索源として十分に研究が行われていない海洋生物を研究材料として、薬物の薬効減弱を防ぐ新たな医薬品のリード化合物の創出を目指して研究を進めている。
    本年度は、昨年度までにAmphidinium属の3種の渦鞭毛藻から単離した、2個のマクロリドおよび1個の長鎖ポリケチド、Agelas属、Dysidea属、Hippospongia属、Pseudoseratina属およびSuberea属の海綿動物から単離した、1個のジテルペノイド、1個のポリヒドロキシステロール、5個のメロテルペノイド、3個のブロモチロシンアルカロイドについて、2次元NMRスペクトルおよび計算化学により得られたデータに基づいて立体化学の解析を行い、未決定であった立体化学の一部を明らかにした。また、新たにSymbiodiniaceae科の2種の渦鞭毛藻と、Alteromonas属やVibrio属などの4種の海洋細菌の培養を行い、それらの抽出物およびStylissa属などの2種の海綿動物の抽出物を用いて、新規化合物の探索を開始した。

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  • Development of new anti-infective drugs from dinoflagellate

    Grant number:17K08345  2017.04 - 2020.03

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

    KUBOTA Takaaki

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    Grant amount:\4810000 ( Direct expense: \3700000 、 Indirect expense:\1110000 )

    The search for new antifungal and antiprotozoal natural products from marine organisms was performed. As a result, twenty-six new natural products were isolated from marine dinoflagellates and sponges, and the structures of six new compounds were elucidated. Among them, one macrolide from dinoflagellates and two alkaloids from a sponge exhibited cytotoxicity against murine leukemia cell line L1210 in vitro. While one alkaloid from a sponge exhibited antimalarial activities against a drug-resistant and a drug-sensitive strains of Plasmodium falciparum. The investigation about antifungal and antiprotozoal activities of other new compounds were currently in progress.

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  • Development of new antitrypanosomal drugs from marine alkaloids

    Grant number:25460115  2013.04 - 2016.03

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

    KUBOTA Takaaki, KOBAYASHI Jun'ichi, KATAKURA Ken, GONOI Tohru

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    Grant amount:\5200000 ( Direct expense: \4000000 、 Indirect expense:\1200000 )

    The search for new anti-trypanosomal natural products from marine organisms was performed. As a result, seventeen new natural products were isolated from marine sponges and dinoflagellates, and the structures of new compounds were elucidated. Three new compounds were analogs of anti-trypanosomal natural products previously found by us. These compounds were isolated to analyze the structure activity relationships of anti-trypanosomal natural products. The detailed investigation about anti-trypanosomal activity of new compounds were currently in progress.

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  • Development of new antitumor agents and immunosuppressive agents using brasilicardin-A as a lead compound

    Grant number:25670043  2013.04 - 2015.03

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

    KOBAYASHI Jun'ichi, KUBOTA Takaaki, ISHIYAMA Haruaki, TANAKA Naonobu

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    Grant amount:\3900000 ( Direct expense: \3000000 、 Indirect expense:\900000 )

    To increase the quantity of our natural products library, 60 new bioactive natural products were isolated from various biological resources and the structures were elucidated. Stereochemistry or mode of action of some known natural products, which were originally found by our group, were also elucidated. However, no System L inhibitor greater than brasilicardin A was found from our natural products library and analogs prepared by chemical conversion from brasilicardin A and its related known natural products.

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  • 渦鞭毛藻由来マクロリドの特異な生合成経路の解明

    Grant number:23108502  2011.04 - 2013.03

    日本学術振興会  科学研究費助成事業  新学術領域研究(研究領域提案型)

    久保田 高明

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\6760000 ( Direct expense: \5200000 、 Indirect expense:\1560000 )

    研究代表者らが海洋渦鞭毛藻Amphidinium sp.から単離、構造決定している一連の抗腫瘍性マクロリドであるアンフィジノリド類のポリケチド鎖は、13C標識酢酸の投与実験により、通常の酢酸-マロン酸経路だけでは説明できない特異な炭素鎖伸長経路により生合成されていることが分かっている。この特異な炭素鎖伸長経路は、他の属の渦鞭毛藻が生産するポリケチドの生合成にも関与していることが示唆されている。
    植物や菌類のポリケチド生合成酵素(PKS)は、酢酸由来の2炭素を直列に2炭素ずつポリケチド鎖を伸長する事しかできないが、渦鞭毛藻のPKSはポリケチド鎖を2炭素伸長させるだけでなく、酢酸のメチル基炭素を用いて1炭素のみ伸長させることも可能と考えられる。生合成工学的手法により、渦鞭毛藻のPKSを利用することが可能になれば、菌類に比べて培養が困難な渦鞭毛藻のポリケチドを、他のホストで効率よく生産させることが可能になるだけでなく、既知のPKSでは生産することができない多彩な炭素骨格の化合物を、酵素的に合成することも可能となる。しかし、この特異な1炭素伸長のメカニズムは不明である。
    本研究では、2011年に採取したアンフィジノリド生産株について、RNA-Seq解析によるmRNAの網羅的な解析を行った結果、アンフィジノリド類の生合成に関与している可能性のある遺伝子として、既知のPKSに見られる酵素や、β-メチル化に関与する酵素と相同性を示す酵素遺伝子の他、藍藻の生産するバルバミドの生合成において特異な炭素鎖伸長に関与している酵素と相同性を示す、非リボソームペプチド合成酵素に見られるドメインとPKSの混合したモジュール型酵素の遺伝子を取得した。

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  • Research and development of bioactive marine natural products

    Grant number:20390001  2008 - 2010

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

    KOBAYASHI Jun'ichi, KUBOTA Takaaki, ISHIYAMA Haruaki

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid)  Grant type:Competitive

    Grant amount:\19760000 ( Direct expense: \15200000 、 Indirect expense:\4560000 )

    Investigation of extracts of an Okinawan marine organisms (sponge, tunicate, and dinoflagellate etc.) resulted in the isolation of new manzamine alkaloids exhibiting antimalarial and antitrypanosomal activities, new pyridinium alkaloids exhibiting acetylcholine esterase inhibitory activity, and new terpenoid quinones exhibiting tyrosine kinase inhibitory activity. In addition, many new compounds that show cytotoxic activity (pyridine alkaloids, beta-carboline alkaloids, bromotyrosine alkaloids, a macrolide, and sesquiterpenoids) and anti-microbial activity (bromopyrrole alkaloids, bromotyrosine alkaloids, triterpenoids) were isolated from the marine organisms. The absolute stereochemistries of known cytotoxic macrolides, previously isolated from dinoflagellete by our group, were also elucidated.

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  • 創薬素材としての細胞骨格系機能性分子の探索

    Grant number:18032005  2006 - 2007

    日本学術振興会  科学研究費助成事業  特定領域研究

    小林 淳一, 久保田 高明, 石山 玄明, 津田 正史

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid)  Grant type:Competitive

    Grant amount:\6200000 ( Direct expense: \6200000 )

    本研究では、海洋生物、植物、微生物などの広範な天然資源を素材として、細胞骨格系において重要な役割を果たしているアクチンおよびチューブリン等を分子標的にしたスクリーニングを行うことにより、これらの蛋白質の重合・脱重合を阻害する新しい天然分子を見い出すとともに、これらの天然分子の構造活性相関を検討し、特異な重合阻害剤や脱重合阻害剤(重合促進剤)を開発する目的で研究を行った。以下に本年度の研究成果の概要を報告する。アクチンファイバーの安定化促進作用を有する渦鞭毛藻由来マクロリド化合物アンフィジノリドHの関連化合物として、渦鞭毛藻より、アンフィジノラクトンB、アンフィジノリドB6,B7およびイリオモテオリド1aを単離、構造決定した。イリオモテオリド1aについては、human Blymphocyte DG-75 cellsに対する作用を調べた結果、アンフィジノリドHと同程度の細胞毒性を示すこと見い出した。また、強力なチューブリン脱重合阻害作用と抗癌作用を示すイチイ科植物由来め化合物・タキソールの関連化合物として、日本産イチイよりタキセゾピジンOおよびPを単離、構造決定した。今回単離、構造解析した化合物については、分子標的に対する詳細な活性評価、および各種ヒト腫瘍パネルに対するin vitro、in vivoでの活性を評価し、開発した阻害剤あるいは促準剤の新しい癌治療薬等としての可能性を...

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  • フォトンフォース計測技術を用いた細胞系ダイナミック分析法の開発

    Grant number:17034001  2005 - 2006

    日本学術振興会  科学研究費助成事業  特定領域研究

    笹木 敬司, 久保田 高明, 山本 隆晴

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid)  Grant type:Competitive

    Grant amount:\4900000 ( Direct expense: \4900000 )

    これまでに我々は、フォトンフォース(光の放射圧)を利用して単一徴粒子やマイクロ・ナノ構造体に作用するフェムトニュートンオーダーの力を計測し、表面電荷・吸収・粘弾性特性・吸着力等の物性を非接触・非破壊的に解析する新しい手法を提案するとともに、高精度かつ汎用性の高い計測システムを開発してきた。本特定領域研究では、フォトンフォース計測技術を単一細胞や複数細胞集団の新しい分析法として応用し、細胞系のダイナミック分析を実現することを目的として、a)新しいアイデアに基づく2ビームフォトンフォース計測システムを開発、b)単一細胞の粘弾性特性や表面修飾した徴粒子との相互作用ポテンシャルを計測、c)細胞間の接着特性や徴細構造を持つ基板への付着特性の解析、を課題として研究を展開した。細胞と徴粒子あるいは細胞間の相互作用ポテンシャルの解析を実現するために、偏光の異なる2つのパルスレーザービームを個々に照射し、透過散乱光を偏光で分離して同時3次元ポジションセンシングを可能とする新しいフォトンフォース計測システムを試作し、感度、精度について検証した上で、2つの微粒子間の相互作用の解析に応用した。また、フォース計測システムにより細胞の各ポジションの表面弾性や粘性を解析して、細胞が固有の形態で運動するメカニズムの解明を試みている。さらに、細胞間の選択的接着特性を解析するために、外部環境を変えながら細胞間の...

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  • 蛋白質リン酸化を標的とした新規抗腫瘍性シーズの探索

    Grant number:17035004  2005

    日本学術振興会  科学研究費助成事業  特定領域研究

    津田 正史, 小林 淳一, 久保田 高明

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid)  Grant type:Competitive

    Grant amount:\3200000 ( Direct expense: \3200000 )

    海洋生物からの生物活性物質探索の一環として、本研究では、海洋由来真菌Penicillium citrinum N055株より、新規4環性アルカロイドPerinadin Aを単離し、絶対立体配置を含む化学構造を明らかにした。同じくP.citrinum N059株より、5環性アルカロイドCitrinadin Aとともに新規化合物Citrinadin Bを単離し、Citrinadin AとBの絶対立体配置を含む化学構造を推定した。沖縄県辺戸岬沖にて採取したアオブダイの消化管より分離した真菌P.citrinum N05株の培養液の上清より、新規アルカロイドPerinadin Aを得た。Perinadin Aは、光学活性な無色の非結晶性固体として得られ、HRESIMSより分子式がC_<28>H_<37>NO_2であることが明らかとなった。2D NMRデータの詳細な解析に基づいて、Perinadin Aの相対立体配置を含む化学構造を帰属した。CDスペクトルの解析より、絶対立体配置を1S、3R、4R、2'R、3'Sであると帰属した。C-7'はエピ体の混合物であると推定した。沖縄県辺戸岬沖にて採取した紅藻より分離した真菌P.citrinum N059株の培養液の菌体より、新規アルカロイドCitrinadin Bを、既知関連化合物Citrinadin Aとともに単離した。2D NMRデータの詳...

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  • がん分子標的に特異的に作用する天然薬物の開発

    Grant number:17016003  2005

    日本学術振興会  科学研究費助成事業  特定領域研究

    小林 淳一, 久保田 高明, 石山 玄明

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid)  Grant type:Competitive

    Grant amount:\3100000 ( Direct expense: \3100000 )

    研究代表者らはこれまでに、広範な天然資源より種々の分子標的阻害物質を数多く見い出しており、そのいくつかは新しい医薬リード化合物として開発研究が展開される一方、生体機能解明のためのバイオプローブとして利用されている。本研究では、海洋生物、植物、微生物などの広範な天然資源を素材として、チューブリン、トポイソメラーゼ、ヒストンデアセチラーゼ、チロシンキナーゼ、等の分子標的に対するスクリーニングを行うことにより、新しいがん分子標的阻害物質を見い出すことを目的とし、以下の研究を行った。放線菌Nocardia brasiliensisより単離した免疫抑制物質ブラシリカルジンAのアナログを調製し構造活性相関について研究を行った。現在、ビオチン誘導体を用いて、分子標的の特定を行っている。一方、アクチンファイバーの安定化を促進させる作用を有する海洋共生渦鞭毛藻由来マクロリド化合物・アンフィジノリドHの溶液中のコンホメーション解析を行うとともに、関連抗腫瘍性マクロリドとしてアンフィジノリドB4およびB5を単離構造決定した。また、沖縄産群体ホヤEudistoma cf.rigidaより単離した抗腫瘍性マクロリド化合物・イエジマリド類の絶対立体配置を決定した。今後、活性を示した化合物については、構造活性相関を通じて、より特異性の高い分子標的阻害物質を分子設計する予定である。さらに、得られた分子標的阻...

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  • 抗腫瘍性マクロリド・イエジマリド類の真の生産微生物の解明

    Grant number:16651104  2004 - 2005

    日本学術振興会  科学研究費助成事業  萌芽研究

    小林 淳一, 津田 正史, 久保田 高明

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid)  Grant type:Competitive

    Grant amount:\2900000 ( Direct expense: \2900000 )

    沖縄産群体ホヤEudistoma cf.rigidaより単離したイエジマリド類は、旅線菌などの二次代謝産物にみられるアミノ酸結合型ポリケチドであり、ホヤの体内に共生する微生物が生産しているものと推定される。そこで本研究では、共生微生物を含むホヤの全ゲノムDNAより、イエジマリド合成酵素遺伝子のクローニングを行い、イエジマリドの生合成経路の遺伝子レベルでの解明、および、分子マーカーと免疫学的手法を駆使してイエジマリド類の真の生産微生物の特定を目的として研究を行った。まず、これまで不確定であったイエジマリド類の立体化学について、NMRデータ解析、酸化分解生成物の立体選択的合成、化学相関実験により、全絶対立体配置を確定した。次にポリケチド合成酵素のKetosynthaseドメインに特異的な遺伝子プローブや、非リボゾーム型ペプチド合成酵素の遺伝子プローブを種々設計し、沖縄で採取したホヤについて、ゲノムDNAを分離精製するとともに、ホヤの全DNAよりコスミドライブラリーの作成を行った。作成した遺伝子プローブをプライマーとしてホヤゲノムDNAについてPCRを行い、PCR生成物よりプラスミドDNAを調製した。特異的なパターンを示す遺伝子については、DNAシークエンサーで塩基配列を決定し、その塩基配列に基づいた特異的な遺伝子プローブを設計した。今後これら特異的遺伝子プローブを用いて、コスミド...

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  • Research and development of bioactive natural products targeting cytoskeleton.

    Grant number:16310143  2004 - 2005

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

    KOBAYASHI Jun'ichi, TSUDA Masashi, KUBOTA Takaaki, ISHIYAMA Haruaki

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid)  Grant type:Competitive

    Grant amount:\13500000 ( Direct expense: \13500000 )

    1)Eight stilbenoids, 1-(p-hydroxybenzyl)-4,8-dimethoxyphenanthrene-2,7-diol (1), 2,7-dihydroxy-1,3-bis(p-hydroxybenzyl)-4-methoxy-9,10-dihydrophenanthrene (2), 4,7-dihydroxy-1-(p-hydroxyberzyl)-2-methoxy-9,10-dihydrophenanthrene (3), 3,3'-dihydroxy- 2',6'-bis(p-hydroxybenzyl)-5-methoxybibenzyl (4), 3',5-dihydroxy-2-(p-hydroxybenzyl)-3-methoxybibenzyl (5), blestriarenes B (6) and C (7), and blestrianol A (8) have been isolated by the guidance of inhibitory effect of tubulin polymerization from the tubers of Bletilla striata (Orchidaceae). Among them, 4 and 5 inhibited the polymerization of t...

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  • 渦鞭毛藻由来マクロリドamphidinolide Cの立体化学と生合成経路の解明

    Grant number:01J10818  2001 - 2002

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

    久保田 高明

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    Grant amount:\2000000 ( Direct expense: \2000000 )

    海洋産の渦鞭毛藻Amphidinium sp.の培養藻体から単離した抗腫瘍性25員環マクロリド・Amphidinolide Cは、テトラヒドロフラン環、共役ジエン(S-cisおよびS-trans)、水酸基、エキソメチレン、エステルカルボニル基、ケトカルボニル基、といった多彩な官能基・部分構造を持ち、12個の不斉炭素を有するユニークで複雑な構造の化合物である。しかしながらこれまで、Amphidinolide Cの立体化学については、一部の相対立体配置の推定がなされているのみであり、作用メカニズムの解明および構造活性相関についての研究が展開できない状況にある。一方、Amphidinolide Cは奇数員環のマクロリドで、隣接するメチル基-エキソメチレン基を有するなど通常のポリケチド生合成経路では説明のつかない炭素骨格を有しており、その生合成経路についても興味が持たれる。本研究では、Amphidinolide Cの絶対立体配置を解明し、合成研究とそれに続く活性評価を可能にするとともに、生合成経路の解明を目的として研究を行った。
    1)Amphidinolide CのC-1〜C-10とC-17〜C29に相当するセグメントを合成し、天然物由来の反応生成物とスペクトルデータを比較により、3位、4位、6位、7位、8位、20位、23位および24位の絶対立体配置を決定した。
    2)Amphidinolide Eについて、NMRデータの解析、分解反応、セグメントの合成により、8個の不斉炭素の絶対立体配置を明らかにした。

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  • Search for bioactive natural products and its biosynthesis

    1995

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    Grant type:Competitive

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  • 生物活性天然物質の探索と生合成

    1995

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Class subject in charge

  • Advanced Seminars in Drug Discovery and Drug Development (Natural Product Chemistry) (2023academic year) special  - その他

  • Experimental Organic Chemistry (2023academic year) 1st and 2nd semester  - その他5~9

  • Experimental Organic Chemistry (2023academic year) 1st and 2nd semester  - その他5~9

  • Natural Products Chemistry (2023academic year) 1st and 2nd semester  - 木5~6

  • Natural Products Chemistry (2023academic year) 1st and 2nd semester  - 木5~6

  • Introduction to Natural Product Chemistry (2023academic year) special  - その他

  • Introduction to Natural Product Chemistry (2023academic year) special  - その他

  • Seminar on Natural Product Chemistry (2023academic year) special  - その他

  • Advanced Lectures: Natural Products Chemistry (2023academic year) special  - その他

  • Natural Products Chemistry 1 (2023academic year) 1st semester  - 木5~6

  • Natural Products Chemistry 1 (2023academic year) 1st semester  - 木5~6

  • Natural Products Chemistry 2 (2023academic year) Second semester  - 木5~6

  • Natural Products Chemistry 2 (2023academic year) Second semester  - 木5~6

  • Organic Chemistry and Natural Products Chemistry (2023academic year) special  - その他

  • Organic Chemistry and Natural Products Chemistry (2023academic year) special  - その他

  • Introduction to Kampo Medicine 1 (2023academic year) Third semester  - 金5~6

  • Introduction to Kampo Medicine 1 (2023academic year) Third semester  - 金5~6

  • Introduction to Kampo Medicine A (2023academic year) Third semester  - 金5~6

  • Introduction to Kampo Medicine A (2023academic year) Third semester  - 金5~6

  • International Collaborative Pharmaceutical Education(Field Studies Overseas) (2023academic year) special  - その他

  • International Collaborative Pharmaceutical Education(Field Studies Overseas) (2023academic year) special  - その他

  • International Collaborative Pharmaceutical Education(Field Studies Overseas) (2023academic year) special  - その他

  • International Collaborative Pharmaceutical Education(Field Studies Overseas) (2023academic year) special  - その他

  • Pharmacognosy (2023academic year) 3rd and 4th semester  - 金1~2

  • Pharmacognosy (2023academic year) 3rd and 4th semester  - 金1~2

  • Pharmacognosy 1 (2023academic year) Third semester  - 金1~2

  • Pharmacognosy 1 (2023academic year) Third semester  - 金1~2

  • Pharmacognosy 2 (2023academic year) Fourth semester  - 金1~2

  • Pharmacognosy 2 (2023academic year) Fourth semester  - 金1~2

  • Guidance for Pharmaceutical Sciences (2023academic year) 1st and 2nd semester  - [第1学期]水4, [第2学期]月1

  • Guidance for Pharmaceutical Sciences (2023academic year) 1st and 2nd semester  - [第1学期]水4, [第2学期]月1

  • Practice in Fundamental Pharmaceutical Sciences II (2023academic year) 1st and 2nd semester  - その他5~9

  • Practice in Fundamental Pharmaceutical Sciences II (2023academic year) 1st and 2nd semester  - その他5~9

  • Chemistry of medicinal natural products I (2023academic year) special  - その他

  • Chemistry of medicinal natural products II (2023academic year) special  - その他

  • Familiar medicinal herbs and poisonous plants (2023academic year) 1st semester  - 木7~8

  • Natural Products Chemistry (2022academic year) 1st and 2nd semester  - 木5~6

  • Natural Products Chemistry (2022academic year) 1st and 2nd semester  - 木5~6

  • Introduction to Natural Product Chemistry (2022academic year) special  - その他

  • Seminar on Natural Product Chemistry (2022academic year) special  - その他

  • Natural Products Chemistry 1 (2022academic year) 1st semester  - 木5~6

  • Natural Products Chemistry 1 (2022academic year) 1st semester  - 木5~6

  • Natural Products Chemistry 2 (2022academic year) Second semester  - 木5~6

  • Natural Products Chemistry 2 (2022academic year) Second semester  - 木5~6

  • Organic Chemistry and Natural Products Chemistry (2022academic year) special  - その他

  • Introduction to Kampo Medicine 1 (2022academic year) Third semester  - 金5~6

  • Introduction to Kampo Medicine 1 (2022academic year) Third semester  - 金5~6

  • Introduction to Kampo Medicine 2 (2022academic year) Fourth semester  - 金5~6

  • Introduction to Kampo Medicine 2 (2022academic year) Fourth semester  - 金5~6

  • Introduction to Kampo Medicine A (2022academic year) Third semester  - 金5~6

  • Introduction to Kampo Medicine A (2022academic year) Third semester  - 金5~6

  • Introduction to Kampo Medicine B (2022academic year) Fourth semester  - 金5~6

  • Introduction to Kampo Medicine B (2022academic year) Fourth semester  - 金5~6

  • Pharmacognosy (2022academic year) 3rd and 4th semester  - 金1~2

  • Pharmacognosy (2022academic year) 3rd and 4th semester  - 金1~2

  • Pharmacognosy 1 (2022academic year) Third semester  - 金1~2

  • Pharmacognosy 1 (2022academic year) Third semester  - 金1~2

  • Pharmacognosy 2 (2022academic year) Fourth semester  - 金1~2

  • Pharmacognosy 2 (2022academic year) Fourth semester  - 金1~2

  • Guidance for Pharmaceutical Sciences (2022academic year) 1st and 2nd semester  - [第1学期]水4, [第2学期]月7

  • Guidance for Pharmaceutical Sciences (2022academic year) 1st and 2nd semester  - [第1学期]水4, [第2学期]月7

  • Guidance for Pharmaceutical Sciences (2022academic year) 1st and 2nd semester  - [第1学期]水4, [第2学期]月7

  • Guidance for Pharmaceutical Sciences (2022academic year) 1st and 2nd semester  - [第1学期]水4, [第2学期]月7

  • Practice in Fundamental Pharmaceutical Sciences II (2022academic year) 1st and 2nd semester  - その他5~9

  • Practice in Fundamental Pharmaceutical Sciences II (2022academic year) 1st and 2nd semester  - その他5~9

  • Chemistry of medicinal natural products I (2022academic year) special  - その他

  • Chemistry of medicinal natural products II (2022academic year) special  - その他

  • Familiar medicinal herbs and poisonous plants (2022academic year) 1st semester  - 木7~8

  • Medicinal Sciences (2021academic year) Second semester  - 金5~6

  • Medicinal Sciences (2021academic year) Third semester  - 金5~6

  • Introduction to Natural Product Chemistry (2021academic year) special  - その他

  • Seminar on Natural Product Chemistry (2021academic year) special  - その他

  • Natural Products Chemistry 1 (2021academic year) 1st semester  - 木7,木8

  • Natural Products Chemistry 1 (2021academic year) 1st semester  - 木7,木8

  • Natural Products Chemistry 2 (2021academic year) Second semester  - 木7,木8

  • Natural Products Chemistry 2 (2021academic year) Second semester  - 木7,木8

  • Organic Chemistry and Natural Products Chemistry (2021academic year) Late  - その他

  • Introduction to Kampo Medicine 1 (2021academic year) Third semester  - 金5,金6

  • Introduction to Kampo Medicine 1 (2021academic year) Third semester  - 金5,金6

  • Introduction to Kampo Medicine 2 (2021academic year) Fourth semester  - 金5,金6

  • Introduction to Kampo Medicine 2 (2021academic year) Fourth semester  - 金5,金6

  • Pharmacognosy (2021academic year) 3rd and 4th semester  - 金1,金2

  • Pharmacognosy (2021academic year) 3rd and 4th semester  - 金1,金2

  • Pharmacognosy 1 (2021academic year) Third semester  - 金1,金2

  • Pharmacognosy 1 (2021academic year) Third semester  - 金1,金2

  • Pharmacognosy 2 (2021academic year) Fourth semester  - 金1,金2

  • Pharmacognosy 2 (2021academic year) Fourth semester  - 金1,金2

  • Guidance for Pharmaceutical Sciences (2021academic year) 1st and 2nd semester  - [第1学期]水4, [第2学期]月1

  • Guidance for Pharmaceutical Sciences (2021academic year) 1st and 2nd semester  - [第1学期]水4, [第2学期]月1

  • Guidance for Pharmaceutical Sciences (2021academic year) 1st and 2nd semester  - [第1学期]水4, [第2学期]月1

  • Guidance for Pharmaceutical Sciences (2021academic year) 1st and 2nd semester  - [第1学期]水4, [第2学期]月1

  • Practice in Fundamental Pharmaceutical Sciences II (2021academic year) 1st and 2nd semester  - その他6~9

  • Practice in Fundamental Pharmaceutical Sciences II (2021academic year) 1st and 2nd semester  - その他6~9

  • Chemistry of medicinal natural products I (2021academic year) special  - その他

  • Chemistry of medicinal natural products II (2021academic year) special  - その他

  • Chemistry of Functional Natural Products 1 (2020academic year) Fourth semester  - その他

  • Chemistry of Functional Natural Products 1 (2020academic year) Fourth semester  - その他

  • Chemistry of Functional Natural Products 2 (2020academic year) Fourth semester  - その他

  • Chemistry of Functional Natural Products 2 (2020academic year) Fourth semester  - その他

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