Main ginseng saponin metabolites formed by intestinal bacteria.

Ginseng saponin metabolites produced by human intestinal bacteria and the urinary and blood compounds after oral administration of Ginseng extract and its saponins in human and specific pathogen-free rats were examined in order to elucidate their metabolites absorbed from the intestines. The main metabolites of ginsenosides Rb1, Rb2, Rc, Re, and Rg1 after anaerobic incubation with fecal flora were identified as 20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol (I) 20-O-[alpha-L-arabinopyranosyl (1-->6)-beta-D-glucopyranosyl]-20(S)-protopanaxadiol (II), 20-O-[alpha-L- arabinofuranosyl(1-->6)-beta-D-glucopyranosyl]-20(S)-protopanaxadiol+ ++ (III), and 20(S)-protopanaxatriol (IV), though the metabolic rate and mode were affected by fermentation media. Furthermore, metabolites I-IV and 20(S)-protopanaxadiol (XII) were detected in blood (0.3-5.1 micrograms/ml) and in urine (2.2-96 micrograms/ day) after the oral administration of Ginseng extract (150 mg/ kg/day) to human and of total saponin (1 g/kg/day) to rats.