Metabolism of ginsenoside Rc by human intestinal bacteria and its related antiallergic activity

When ginsenoside R, was anaerobically incubated with human fecal microflora, all specimens metabolized ginsenoside R, to compound K and protopanaxadiol. The main metabolite was compound K. Among the bacteria isolated from human fecal microflora, most bacteria, such as Bacteroides sp., Eubacterium sp., and Bifidobacterium sp. potently transformed ginsenoside R-c to compound K. Bifidobacterium K-103 and Eubacterium A-44 transformed it to compound K via ginsenoside R-d, and Bacteroides HJ-15 and Bifidobacterium K-506 metabolized to compound K via ginsenoside Mb, which was isolated as a new metabolite (M.W. 940[+Na]). Among ginsenoside R, and its metabolites, compound K exhibited the most potent antiallergic activity on the IgE-induced RBL cell line as well as potent cytotoxic activity against tumor cell lines.