Structure and cytotoxicity of steroidal glycosides from Allium schoenoprasum.

A phytochemical analysis of the whole plant of Allium schoenoprasum, has led to the isolation of four spirostane-type glycosides (1-4), and four known steroidal saponins. Their structures were elucidated mainly by 2D NMR spectroscopic analysis and mass spectrometry as (20S,25S)-spirost-5-en-3β,12β,21-triol 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (1), (20S,25S)-spirost-5-en-3β,11α,21-triol 3-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside (2), laxogenin 3-O-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-glucopyranoside (3), and (25R)-5α-spirostan-3β,11α-diol 3-O-β-D-glucopyranosyl-(1→3)-[β-D-glucopyranosyl-(1→4)]-β-D-galactopyranoside (4). Four of the isolated compounds were tested for cytotoxic activity against the HCT 116 and HT-29 human colon cancer cell lines.