Biotransformation of ginsenosides Rb 1 , Rg 3 and Rh 2 in rat gastrointestinal tracts

Background Ginsenosides such as Rb 1 , Rg 3 and Rh 2 are major bioactive components of Panax ginseng . This in vivo study investigates the metabolic pathways of ginsenosides Rb 1 , Rg 3 and Rh 2 orally administered to rats. Methods High performance liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (MS-MS) techniques, particularly liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS), were used to identify the metabolites. Results Six metabolites of Rb 1 , six metabolites of Rg 3 and three metabolites of Rh 2 were detected in the feces samples of the rats. Rh 2 was a metabolite of Rb 1 and Rg 3 , whereas Rg 3 was a metabolite of Rb 1 . Some metabolites such as protopanaxadiol and monooxygenated protopanaxadiol are metabolites of all three ginsenosides. Conclusion Oxygenation and deglycosylation are two major metabolic pathways of the ginsenosides in rat gastrointestinal tracts.