薤白中两种新呋甾皂甙的结构

STUDIES ON TWO NEW FUROSTANOL GLYCOSIDES FROM ALLIUM MACROSTEMON BUNGE

自中药薤白(Allium macrostemon Bunge)鳞茎中分得三种甾体皂甙。经过化学降解和光谱(UV、IR,MS,~1H-NMR,^(13)C-NMR和FAB-MS)分析,鉴定其结构分别为(25R)-26-O-β-D-吡喃葡萄糖-5α-呋甾-20(22)-烯-3β,26-二醇-3-O-β-D-吡喃葡萄糖基(1→2)[β-D-吡喃葡萄糖基(1→3)]-β-D-吡喃葡萄精基(1→4)-β-D-吡喃半乳糖甙(Ⅰ),(25R)-26-O-β-D-吡喃葡萄糖基-5β-呋甾-20(22)-烯-3β,26-二醇-3-P-β-D-吡喃葡萄糖基(1→2)-β-D-吡喃半乳糖甙(Ⅱ)和异菝契皂甙元-3-O-D-吡喃葡萄糖基(1→2)-β-D-吡喃半乳糖甙(Ⅵ)。Ⅰ和Ⅱ为新的呋甾皂甙,分别命名为薤白甙戊和莲白甙己,初步药理实验测试二青均有较强的抑制ADP诱导的人血小板聚集作用。

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, ^(13)C-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 ritro. The IC_(50) of the former was 0.417 mM and that of the latter was 0.020 mM.