To search for cytotoxic components from Allium victorialis, MTT assays on each extract and an isolated component,
gitogenin 3-O-lycotetroside, were performed against
cancer cell lines. Cytotoxicities of most extract were shown to be comparatively weak, though IC50 values of CHCl3 fraction was found to be <31.3-368.4 microg/ml. From the incubated
methanol extract at 36 degrees C, eleven kinds of organosulfuric flavours were predictable by GC-MS performance. The most abundant peak was revealed to be
2-vinyl-4H-1,3-dithiin (1) by its mass spectrum. Further, this extract showed significant cytotoxicities toward
cancer cell lies.
Silica gel column chromatography of the
n-butanol fraction led to the isolation of
gitogenin 3-O-lycotetroside (3) along with
astragalin (4) and
kaempferol 3, 4'-di-O-beta-D-glucoside (5). This steroidal
saponin exhibited significant cytotoxic activities (IC50, 6.51-36.5 microg/ml) over several
cancer cell lines. When compound 3 was incubated for 24 h with human intestinal bacteria, a major metabolite was produced and then isolated by
silica gel column chromatography. By examining parent- and prominent ion peak in FAB-MS spectrum of the metabolite, the structure was speculated not to be any of prosapogenins of 3, suggesting that
spiroketal ring were labile to the bacterial reaction. These suggest that
disulfides produced secondarily are the antitumor principles.