Metabolism of Ginseng Saponins and Its Significance

To follow the metabolic fate of aglycone of ginseng saponins,in vitro and in vivo experiments were performed. Incubation of 20(S)-prtopanaxatriol (1) with rat liver S9 fraction afforded unique ocotillol derivatives, 20, 24-epoxysides (3 and 4). Also 20(S)-prtopanaxadiol (2) gave the corresponding epoxides (5). Healthy volunteers were taken with Sanchi Ginseng, which contains protopanaxatriol and protopanaxadiol saponins and no ocotillol saponins. From the alkaline hydrolysate of the urine samples of these volunteers,3 was detected as well as 1, and the ratio of 3/1 increased up to 2.0 at the maximum at 50 hrs. Biochemical significance of the ocotillol derivatives is discussed, since the main bioactive saponin in Panax vietnamensis is an ocotillol-type saponin, majonoside R2 (7).