研究者詳細 - 久保田　高明

27 海洋共生藻由来の新規長鎖ポリヒドロキシ化合物Amphezonol Aの構造と生合成研究(口頭発表の部)

久保田高明, 佐久間祐介, 新保和高, 津田正史, 魚住泰広, 小林淳一

天然有機化合物討論会講演要旨集 47 ( 0 ) 151 - 156 2005年

記述言語：日本語出版者・発行元：天然有機化合物討論会実行委員会

DOI： 10.24496/tennenyuki.47.0_151

Amphidinolide Eの立体化学

久保田高明, 津田正史, 小林淳一

日本化学会講演予稿集 81st ( 2 ) 707 2002年3月

Amphidinolide類の生合成に関する研究

津田正史, 久保田高明, 新保和高, 堀口健雄, 勝又和人, 小林淳一

日本化学会講演予稿集 80th 3 2001年9月

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年3月

17 Amphidinolide CおよびT1〜T5の立体構造(口頭発表の部)

久保田高明, 津田正史, 遠藤哲哉, 城始勇, 小林淳一

天然有機化合物討論会講演要旨集 43 ( 0 ) 97 - 102 2001年

記述言語：日本語出版者・発行元：天然有機化合物討論会実行委員会

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

17 Amphidinolide CおよびT1〜T5の立体構造(口頭発表の部)

久保田高明, 津田正史, 遠藤哲哉, 城始勇, 小林淳一

天然有機化合物討論会講演要旨集 43 ( 0 ) 97 - 102 2001年

記述言語：日本語出版者・発行元：天然有機化合物討論会実行委員会

DOI： 10.24496/tennenyuki.43.0_97

沖縄産海綿Theonella sp.より単離した新規環状デプシペプチドの構造

新保和高, 久保田高明, 津田正史, 小林淳一

日本化学会講演予稿集 78th ( 2 ) 849 2000年3月

渦鞭毛藻Amphidinium sp.より単離した新規14員環マクロリドAmphidinolide Vの構造

久保田高明, 津田正史, 小林淳一

日本化学会講演予稿集 78th ( 2 ) 884 2000年3月

100(P48) 渦鞭毛藻Amphidinium sp.より単離した新規ポリヒドロキシ化合物Colopsinol AとBの構造(ポスター発表の部)

久保田高明, 津田正史, 高橋美穂, 石橋正己, 小林淳一, 直木秀夫

天然有機化合物討論会講演要旨集 41 ( 0 ) 595 - 600 1999年

記述言語：日本語出版者・発行元：天然有機化合物討論会実行委員会

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

100(P48) 渦鞭毛藻Amphidinium sp.より単離した新規ポリヒドロキシ化合物Colopsinol AとBの構造(ポスター発表の部)

久保田高明, 津田正史, 高橋美穂, 石橋正己, 小林淳一, 直木秀夫

天然有機化合物討論会講演要旨集 41 ( 0 ) 595 - 600 1999年

記述言語：日本語出版者・発行元：天然有機化合物討論会実行委員会

DOI： 10.24496/tennenyuki.41.0_595

渦鞭毛藻Amphidinium sp.より単離した新規ポリオール化合物Luteophanol Bの構造

久保田高明, 津田正史, 土居由貴子, 中道寛子, 石橋正己, 小林淳一

日本薬学会年会要旨集 118th ( 2 ) 108 1998年3月

80(P63) 渦鞭毛藻由来の新規ポリヒドロキシ化合物Luteophanol BおよびCの構造(ポスター発表の部)

久保田高明, 津田正史, 土居由貴子, 高橋彩子, 中道寛子, 石橋正己, 福士江里, 川端潤, 小林淳一

天然有機化合物討論会講演要旨集 40 ( 0 ) 473 - 478 1998年

記述言語：日本語出版者・発行元：天然有機化合物討論会実行委員会

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