Studies on the Constituents of Luffa acutangula ROXB. II. Structures of Acutosides H and I, Oleanolic Acid Saponins Isolated from the Seed

抄録

From the seeds of Luffa acutangula ROXB. (Cucurbitaceae), two 3, 28-O-bisdesmosidic heptaglycosides of oleanolic acid, named acutosides H and I, were isolated and their structures were elucidated. Acutosides H and I have the same prosapogenin structure, oleanolic acid 3-O-[O-α-L-arabinopyranosyl-(1→3)-β-D-glucopyranosyluronic acid] and differ in the structures of the ester-linked sugar moieties. Acutoside H is a 28-O-[O-β-D-xylopyranosyl-(1→3)-O-β-D-xylopyranosyl-(1→4)-[O-β-D-xylopyranosyl(1→3)]-O-α-L-rhamopyranosyl-(1→2)-α-L-arabinopyranosyl] ester, and acutoside I is a 28-O-[O-α-L-arabinopyranosyl-(1→3)-O-β-D-xylopyranosyl-(1→4)-[O-β-D-xylopyranosyl-(1→3)]-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl] ester.