Two novel furostanol saponins from the rhizomes of Dioscorea panthaica Prain et Burkill and their cytotoxic activity

Dioscoresides A and B were isolated from the rhizomes of Dioscorea panyhaica and shown to possess a novel furostanol skeleton. Their structures were fully elucidated as 3-O-[beta -D-glucopyranosyl-(1-->3)-O-alpha -L-rhamnopyranosyl-(1-->2)-beta -D-glucopyranosyl]-26-O-P-20, 22-seco-D-glucopyranosyl-25 (R)-furosta-5-en-20, 22-dione-3 beta, 26-diol and 3-O-[bis-alpha -L-rhamnopyranosyl-(1-->4 and 1-->2)-beta -D-glucopyranosyl]-26-O-beta -D-glucopyranosyl-20, 22-seco-25 (R)-furosta-5-en-20, 22-dione-3 beta, 23(S), 26-triol by spectroscopic techniques and chemical means. These compounds exhibited cytotoxic activity tested in vitro on A375-S2, L929 and Hela cell lines. (C) 2001 Elsevier Science Ltd. All rights reserved.