Steroidal Saponins from the Rhizome of Paris polyphylla and Their Cytotoxic Activities

Two new furostanol saponins and one new spirostanol saponin were isolated from the rhizome of Paris polyphylla Smith var. yunnanensis, together with 18 known steroidal saponins. The structures of the new steroidal saponins were elucidated as 26-O-beta-D-glucopyranosyl-(25R)-5-ene-furost-3 beta, 17 alpha, 22 alpha, 26-tetrol-3-O-alpha-L-arabinofuranosyl-(1 -> 4)-[alpha-L-rhamnopyranosyl-(1 -> 2)]-beta-D-glucopyranoside (2, parisyunnanoside A), 26-O-beta-D-glucopyranosyl-(25R)-5, 20 (22)-diene-furost-3 beta, 26-diol-3-O-alpha-L-arabinofuranosyl-(1 -> 1)-[alpha-L-rhamnopyranosyl-(1 -> 2]-beta-D-glucopyranoside (7, parisyunnanoside B), and (25R)-spirost-5-ene-3 beta, 12 alpha-diol-3-O-alpha-L-rhamnopyranosyl-(1 -> 4)-alpha-L-hamnopyranosyl-(1 -> 4)-[alpha-L-rhamnopyranosyl-(1 -> 2)]-beta-D-glucopyranoside (13, parisyunnanoside C) by MS and 1D and 2D NMR analysis. The isolated compounds were evaluated for their cytotoxicity against HL-60 human promyelocytic leukemia cells. Our results showed that the spirostanol framework of the aglycone and the terminal a-L-rhamnopyranosyl with 1 -> 2 linkage to the sugar chain of saponins at C-3 are essential for their high cytotoxicity, whereas the hydroxy group substitution at C-12 or C-17 of the aglycone causes a reduction in their activity.