Cytotoxic steroidal glycosides from Allium flavum

Three new spirostane-type glycosides (1-3) were isolated from the whole plant of Allium flavum. Their structures were elucidated mainly by 2D NMR spectroscopic analysis and mass spectrometry as (20S,25R)-2 alpha-hydroxyspirost-5-en-3 beta-yl O-beta-D-xylopyranosyl-(1 -> 3)-[beta-D-galactopyranosyl-(1 -> 2)]-beta-D-galactopyranosyl-(1 -> 4)-beta-D-galactopyranoside (1), (20S,25R)-2 alpha-hydroxyspirost-5-en-3 beta-yl O-beta-D-xylopyranosyl-(1 -> 3)-[beta-D-glucopyranosyl-(1 -> 2)]-beta-D-galactopyranosyl-(1 -> 4)-beta-D-galactopyranoside (2), and (20S,25R)-spirost-5-en-3 beta-yl O-alpha-L-rhamnopyranosyl-(1 -> 4)-[beta-D-glucopyranosyl-(1 -> 2)]-beta-D-glucopyranoside (3). The three saponins were evaluated for cytotoxicity against a human cancer cell line (colorectal SW480). (C) 2014 Elsevier B.V. All rights reserved.