79(P2-9) トウダイグサ科植物の加水分解性タンニンオリゴマー(ポスター発表の部) 吉田 隆志 難波 治 横山 晃一 奥田 拓男 陳 玲 天然有機化合物討論会 天然有機化合物討論会講演要旨集 0 31 601 608 1989-09-17 Based on the chromatographic survey which revealed wide distribution of dehydroellagitannins, geraniin (1) and mallotusinic acid (2), in Euphorbia, Mallotus, Aleurites, Sapium and Phyllanthus species of Euphorbiaceous plants, and also on the isolation of euphorbins A (3) and B (4), dimeric hydrolysable tannins, having the geraniin structure as a part of their molecules, from Euphorbia hirta, a further search of oligomers of novel structural units was carried out. Three new dimers, euphorbins C (5), D (6) and E (21) were isolated from the same plant and their structures were elucidated. Euphorbins C and D are dimers of new class which possess, in addition to the geraniin structure in their molecules as in 3 and 4, a unique new tetrameric galloyl (euphorbinoyl) group which is biogenetically regarded as the product of C-O oxidative couplings between two galloyl groups in a monomer and hexahydroxydiphenoyl group in the another monomer. Euphorbin E is the first example of the dimeric hydrolyzable tannins having a dehydroeuphorbinoyl group as a linking unit between two monomers. Euphorbin A (3) and an analogous new dimer, euphorbin F were also isolated from E. tirucallii, the latter of which was found to have structure (26). E. prostrata was found to contain a different type of hydrolyzable tannin oligomers, rugosins D (27), E (28) (dimers) and G (29) (trimer). 1989-09-17 110006678864 AN00154136 JPN NII-ELS 3 79(P2-9) HYDROLYZABLE TANNIN OLIGOMERS FROM EUPHORBIACEOUS PLANTS Yoshida T. Namba O. Yokoyama K. Okuda T. Chen L. Symposium on the chemistry of natural products Based on the chromatographic survey which revealed wide distribution of dehydroellagitannins, geraniin (1) and mallotusinic acid (2), in Euphorbia, Mallotus, Aleurites, Sapium and Phyllanthus species of Euphorbiaceous plants, and also on the isolation of euphorbins A (3) and B (4), dimeric hydrolysable tannins, having the geraniin structure as a part of their molecules, from Euphorbia hirta, a further search of oligomers of novel structural units was carried out. Three new dimers, euphorbins C (5), D (6) and E (21) were isolated from the same plant and their structures were elucidated. Euphorbins C and D are dimers of new class which possess, in addition to the geraniin structure in their molecules as in 3 and 4, a unique new tetrameric galloyl (euphorbinoyl) group which is biogenetically regarded as the product of C-O oxidative couplings between two galloyl groups in a monomer and hexahydroxydiphenoyl group in the another monomer. Euphorbin E is the first example of the dimeric hydrolyzable tannins having a dehydroeuphorbinoyl group as a linking unit between two monomers. Euphorbin A (3) and an analogous new dimer, euphorbin F were also isolated from E. tirucallii, the latter of which was found to have structure (26). E. prostrata was found to contain a different type of hydrolyzable tannin oligomers, rugosins D (27), E (28) (dimers) and G (29) (trimer). 吉田 隆志 Yoshida T. 岡山大・薬 Faculty of Pharmaceutical Sciences, Okayama University 難波 治 Namba O. 岡山大・薬 Faculty of Pharmaceutical Sciences, Okayama University 横山 晃一 Yokoyama K. 岡山大・薬 Faculty of Pharmaceutical Sciences, Okayama University 奥田 拓男 Okuda T. 岡山大・薬 Faculty of Pharmaceutical Sciences, Okayama University 陳 玲 Chen L. 中国福建省中医研 Fujian Institute of Traditional Chinese Medicine