New furostanol saponins from the bulbs of Allium macrostemon Bunge and their cytotoxic activity.

Four new furostanol saponins, named as macrostemonoside O, macrostemonoside P, macrostemonoside Q and macrostemonoside R, along with five known compounds, were isolated from the dried bulbs of Allium macrostemon Bunge. The structures of these new compounds were established by the spectral data elucidation (IR, ESIMS, 1D and 2D NMR) as 26-O-beta-D-glucopyranosyl-22-hydroxyl-5beta-furost-25 (27)-ene-3beta, 26-diol-3-O-beta-D-glucopyranosyl (1-->2)-beta-D-galactopyranoside (macrostemonoside O), (25R)-26-O-beta-D-glucopyranosyl-22-hydroxyl-5beta-furost-1beta, 3beta, 26-triol-3- O-beta-D-glucopyranosyl (1-->2)-beta-D-galactopyranoside (macrostemonoside P), (25R)-26-O-beta-D-glucopyranosyl-22-hydroxy-5beta-furost-1alpha, 2beta, 3beta, 26-tetraol-3-O-beta-D-glucopyranosyl (1-->2)-beta-D-galactopyranoside (macrostemonoside Q) and (25R)-26-O-beta-D-glucopyranosyl-22-hydroxyl-5beta-furost-2alpha, 3beta, 26-triol-3-O-beta-D-glucopyranosyl (1-->2) [beta-D-glucopyranosyl (1-->3)]-beta-D-glucopyranosyl (1-->4)-beta-D-galactopyranoside (macrostemonoside R), respectively. Their cytotoxic activities on several cancer cell lines including solid tumor (HepG2, MCF-7, NCI-H460 and SF-268) and drug resistant tumor (R-HepG2) were investigated and five compounds showed diverse cytotoxity to these cancer cell lines which suggest that they might be used as potential leading compounds to cure cancer diseases.