Two new steroidal saponins from the rhizome of Polygonatum sibiricum

Two new furostanol saponins, polygonoides A (1) and B (2), along with three known compounds, were obtained from the ethanolic extract of the rhizome of Polygonatum sibiricum Redoute. On the basis of acid hydrolysis and comprehensive spectroscopic analyses, the structures of polygonoides A and B were elucidated as (25R)-26-O-beta-D-glucopyranosyl-furost-5,22(23)-dien-3beta,26-diol-3-O-alpha-L-rhamnopyranosyl-(1 --> 3)-beta-D-glucopyranosyl-(1 --> 4)-[alpha-L-rhamnopyranosyl-(1 --> 2)]-beta-D-glucopyranoside (1) and 22 alpha-(propionyloxy)-furost-5-en-3beta,20 alpha-diol-3-O-beta-D-glucopyranosyl-(1 --> 4)-[alpha-L-rhamnopyranosyl-(1 --> 2)]-beta-D-glucopyranoside (2).