Transformation of ginseng saponins to ginsenoside Rh-2 by acids and human intestinal bacteria and biological activities of their transformants

When ginseng water extract was incubated at 60degreesC in acidic conditions, its protopanaxadiol ginsenosides were transformed to ginsenoside Rg(3) and Delta(20)-ginsenoside Rg(3). However, protopanaxadiol glycoside ginsenosides Rb-1, Rb-2 and Rc isolated from ginseng were mostly not transformed to ginsenoside Rg(3) by the incubation in neutral condition. The transformation of these ginsenosides to ginsenoside Rg(3) and Delta(20)-ginsenoside Rg(3) was increased by increasing incubation temperature and time in acidic condition: the optimal incubation time and temperature for this transformation was 5 h and 60degreesC resepectively. The transformed ginsenoside Rg(3) and Delta(20)-ginsenoside Rg(3) were metabolized to ginsenoside Rh-2 and Delta(20)-ginsenoside Rh-2, respectively, by human fecal microflora. Among the bacteria isolated from human fecal microflora, Bacteroides sp., Bifidobacterium sp. and Fusobacterium sp. potently transformed ginsenoside Rg(3) to ginsenoside Rh-2. Acid-treated ginseng (AG) extract, fermented AG extract, ginsenoside Rh-2 and protopanaxadiol showed potent cytotoxicity against tumor cell lines. AG extract, fermented AG extract and protopanaxadiol potently inhibited the growth of Helicobacterpylori.