STUDIES ON TWO NEW FUROSTANOL GLYCOSIDES FROM ALLIUM MACROSTEMON BUNGE

Further studies on the active constituents in the bulbs of Allium macrostemon Bunge led to the isolation and structural determination of two new furostanol saponin macrostemonoside E and F. On the basis of chemical evidences and spectral analysis (UV, IR, ¹H-NMR, ¹³C-NMR and FAB-MS), the structure of macrostemonoside E(Ⅰ) was elucidated as (25R)-26-O-β-D-glucopyranosyl-5α-furost-20 (22)-ene-3β,26-diol-3-O-β-D-glucopyranosyl (1→2) β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→4)-β-D-galactopyranoside; macrostemonoside F(Ⅱ) was established to be (25R)-26-O-β-D-glucopyranosyl-5β-furost-20 (22)-ene-3β, 26-diol-3-O-β-D-glucopyranosyl(l→2)-β-D-galactoside. Preliminary pharmacological tests showed that both macrostemonoside E and F could strongly inhibit ADP-induced human platelet aggregation in vitro. The IC₅₀ of the former was 0.417 mM and that of the latter was 0.020 mM.