Steroidal saponins from the rhizomes of Polygonatum sibiricum

Four new steroidal saponins, named neosibiricosides A-D (1-4), were isolated from the rhizomes of Polygonatum sibiricum, along with two known spirostanol glycosides. The structures of the new glycosides were elucidated by spectroscopic methods and acid hydrolysis as (23S,24R,25R)-1-O-acetylspirost-5-ene-1 beta,3 beta,23,24-tetrol 3-O-beta-D-glucopyranosyl-(1 -> 2)-fi-D-glucopyranosyl-(1 -> 4)-beta-D-fucopyranoside (1), (25S)-1-O-acetylspirost-5-ene-1 beta,3 beta-diol 3-beta-D-glucopyranosyl-(1 -> 2)-[beta-D-xylopyranosyl-(1 -> 3)]-beta-D-glucopyranosyl-(1 -> 4)-beta-D-galactopyranoside (2), (25S)spirost-5-en-3 beta-ol 3-O-beta-D-glucopyranosyl-(1 -> 2)-[beta-D-xylopyranosyl-(1 -> 3)]-beta-D-glucopyranosyl-(1 -> 4)-2-O-acetylfi-D-galactopyranoside (3), and (25R,S)-spirost-5-en-3 beta-of 3-O-beta-D-glucopyranosyl-(1 -> 2)-beta-D-glucopyranosyl-(1 -> 4)fi-D-galactopyranoside (4). The cytotoxic activity of the isolated compounds was evaluated with human MCF-7 breast cancer cells.