著者

吉田 達彦 豊田 正夫 菅 由紀子 高岡 茂 橋本 敏弘 浅川 義範

出版者

天然有機化合物討論会

雑誌

天然有機化合物討論会講演要旨集

巻号頁・発行日

no.38, pp.397-402, 1996-09-02

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Liverworts (Hepaticae) are known to be rich sources of both terpenoids and aromatic compounds with biological activities. The Hepaticae occasionally produce their own peculiar phenolic bis(bibenzyl) derivatives. In the course of our systematic investigation of the chemical constituents of liverworts belonging to the Blasiaceae, we isolated four novel cyclic bis(bibenzyl) dimers, pusilatins A-D (1-4) and two depsides (16, 17) together with nine phenolic compounds (5, 6, 9-15) from Blasia pusilla L. and a novel optically active cyclic bibenzyl-dihydrophenanthrene derivative.(+)-cavicularin (18) from Cavicularia densa Steph. Their structures were characterized by a combination of spectroscopy, X-ray crtstallogarphic analysis and chemical evidences. Further investigation of the phenolic constituents of the thallic liverworts, we isolated a new cyclic bis(bibenzyl) dimer, pusilatin E (8) from Riccardia multifida (L.) S. Gray subsp. decrescens (Steph.) Furuki which was easily derived from riccardin A (7) by coupling reaction using Mn(OAc)_3 ・2H_2O. Previously, we isolated pusilatin D from B. pusilla and proposed the structure (4b) linked by ether C12-O-C1''' bond on the basis of comparison of the ^<13>C NMR data of its acetate with those of the related acethyl compounds. However, the structure (4b) was revised to 4a possessing C10'-O-C11" linkage on the basis of the HMBC analysis. (+)-Cavicularin (18) might be formed by intramolecular phenolic oxidative coupling between 3' and 10' position of riccardin C. On the other hand, riccardin C dimers, pusilatins A-D (1-4) might be biosynthesized by intermolecular coupling between two molecules of riccardin C. These bibenzyl derivatives are significant chemical markers of the Blasiaceae. Pusilatins B (2) and C (3) showed DNA polymerase β inhibitory activity.

著者

豊田 正夫

出版者

公益社団法人 日本薬学会

雑誌

YAKUGAKU ZASSHI (ISSN:00316903)

巻号頁・発行日

vol.120, no.12, pp.1359-1372, 2000-12-01 (Released:2008-05-30)

参考文献数

37

被引用文献数

1 8

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Four hundred samples of Conocephalum conicum, collected in various places have been analyzed by GC-MS. This resulted in the presence of three chemo-types of C. conicum. One of them elaborate (-)-sabinene (type-I) as a major compound. The other two types characteristically contained (+)-bornyl acetate (type-II) and methyl cinnamate (type-III) as major constituent respectively. The structures of three new monoterpenic esters, isolated from the ether extract of C. conicum (type-I and/or II) have been established by chemical and spectral means. They were shown to be monoterpenic esters of (+)-borneol and p-coumaric acid derivatives. The ether extract of the liverwort Chiloscyphus polyanthos afforded sesquiterpenoids which are enantiomeric to those found in another liverwort Lepidozia vitrea. The absolute configurations of the sesquiterpenoids found in the C. polyanthos were determined by spectroscopic evidence, chemical derivatization and/or x-ray crystallographic analysis. The ether extract of the liverwort Porella perrottetiana afforded (-)-α-eudesmol, which showed an opposite sign of the optical rotation to that found in higher plants. Present work on the absolute configuration and an optical purity of (-)-α-eudesmol strongly suggested that the positive values (e.g.+28.5°) described in many previous papers should be revised. Since the absolute configuration of (-)-α-eudesmol was identical to that (+)-β-eudesmol found in the higher plants, it was apparent that the expression of the positive sign might be revised to (-)-α-eudesmol. The optical purity, reconfirmation of the absolute configuration and synthesis of (-)-α-eudesmol will be discussed.