Constituents and the antitumor principle of Allium victorialis var. platyphyllum

To search for cytotoxic components from Allium victorialis, MTT assays on e ach extract and an isolated component, gitogenin 3-O-lycotetroside, were pe rformed against cancer cell lines. Cytotoxicities of most extract were show n to be comparatively weak, though IC50 values of CHCl3 fraction was found to be <31.3-368.4 <mu>g/ml. From the incubated methanol extract at 36 degre esC, eleven kinds of organosulfuric flavours were predictable by CC-MS perf ormance. The most abundant peak was revealed to be 2-vinyl-4H-1,3-dithiin ( 1) by its mass spectrum. Further, this extract showed significant cytotoxic ities toward cancer cell ties. Silica gel column chromatography of the n-bu tanol fraction led to the isolation of gitogenin 3-O-lycotetroside (3) alon g with astragalin (4) and kaempferol 3, 4'-di-O-beta -D-glucoside (5). This steroidal saponin exhibited significant cytotoxic activities (IC50, 6.51-3 6.5 mug/ml) over several cancer cell lines. When compound 3 was incubated f or 24 h with human intestinal bacteria, a major metabolite was produced and then isolated by si(ica gel column chromatography. By examining parent- an d prominent ion peak in FAB-MS spectrum of the metabolite, the structure wa s speculated not to be any of prosapogenins of 3, suggesting that spiroketa l ring were labile to the bacterial reaction. These suggest that disulfides produced secondarily are the antitumor principles.