著者

波多野 力 貴良 礼子 安原 多恵子 奥田 拓男

出版者

天然有機化合物討論会実行委員会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

vol.30, pp.292-299, 1988

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1)Four new hydrolyzable tannins, liquidambin (3), isorugosin A (12), isorugosin B (9) and isorugosin D (13), were isolated from the leaves of Liquidambar formosana. 2) Liquidambin (3), which could be a biogenetic precursor of C-glucosidic tannins, was isolated as an equilibrium mixture. The equilibration was found to be due to hydration of the aldehyde group at C-1 of the glucose residue in 3. 3) Isorugosin D (13), biogenetically producible from two molecules of tellimagrandin II (17), had a valoneoyl group of the orientation different from that of rugosin D (6). Isorugosins A (12) and B (9), monomeric tannins from the same plant, were isomers of rugosins A (4) and B (5) concerning the orientation of valoneoyl group. 4) Rugosins A (4), B (5) and D (6) were absent in L. formosana, and isorugosins A (12), B (9) and D (13) have not been found in Rosa rugosa and Coriaria japonica, which contain 4, 5 and 6. The C-O oxidative coupling in the formation of valoneoyl group in L. formosana, therefore will have been effected by an enzyme different from that of R. rugosa and C. japonica. 5) Cornusiin A, a major component of the fruits of Cornus officinalis, should be formulated as 19, on the basis of the chemical conversion of 19 to isorugosin B (9). Structures of camptothins A and B, which were isolated from the leaves of Camptotheca acuminata, and that of cornusiin C from the Cornus and Camptotheca species, were determined to be 20, 21 and 22, respectively.

著者

波多野 力 枝松 礼 平松 緑 森 昭胤 藤田 勇三郎 安原 多恵子 吉田 隆志 奥田 拓男

出版者

公益社団法人日本薬学会

雑誌

Chemical & pharmaceutical bulletin (ISSN:00092363)

巻号頁・発行日

vol.37, no.8, pp.2016-2021, 1989-08-25

被引用文献数

14 532

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The scavenging effects of twenty-five tannins including low-molecular polyphenols on the superoxide anion radical (O_2^-) generated in the hypoxanthine-xanthine oxidase system were estimated by electron spin resonance (ESR) measurements of the adducts formed by 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and the radical. The scavenging effects of tannins and related polyphenols having ortho-trihydroxyl (pyrogallol) structure [galloyl, hexahydroxydiphenoyl (HHDP) groups in hydrolyzable tannins, galloyl group in acylated proanthocyanidins, and the B-ring of some flavan-3-ols] were stronger than the effects of unacylated proanthocyanidins. The effects of tannins and related polyphenols on the superoxide anion radical were also compared with those on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Each tannin in an ethanol solution of DPPH radical reduced the intensity of the signal of the DPPH radical, and gave a weak signal assignable to a radical derived from that tannin, in a similar way to the appearance of the signal of dl-α-tocopherol radical, accompanied with reduction of the signal of DPPH radical, in a mixture of dl-α-tocopherol and the DPPH radical. In contrast to the case of the superoxide anion radical, the effects of unacylated proanthocyanidins on DPPH radical were comparable with those of the other types of tannins. The scavenging effects of all of the tannins and related polyphenols tested in the experiments on DPPH radical were stronger than that of dl-α-tocopherol.