Transformation of ginsenosides Rg1 and Rb1, and crude Sanchi saponins by human intestinal microflora

Fractions major in ginsenosides Rg(1) and Rb-1 from Sanchi saponins were transformed by human fecal flora. This study yielded the corresponding aglycone, protopanaxatriol, in 49.4% from Rg(1), protopanaxadiol 20-O-glucoside in 54.8% from Rb-1, and dihydroprotopanaxadiol 20-O-glucoside in 87.6% from dihydro Rb-1, by incubation with healthy feces for 70 h in subgram level. Nevertheless large-scale incubation of crude Sanchi saponins revealed the complete biotransformation of Rb-1 and the almost unchanged Rg(1). A small amount of Rg(1) was found to be converted into 20R-ginsenoside Rh-1 and its dehydration product, 20(22)Z-ginsenoside Rh-4.