Anticarcinogenesis in mice by ginseng-hydrolyzing colonic bacteria

Abstract

The present study demonstrated the interrelationship between Ginseng, 20-O-β-D-glucopyranosyl-20(S)-protopanaxadiol (M1), an active Ginseng metabolite formed by intestinal bacteria, and prevention of colon carcinogenesis in C57BL/6 mice colonized with Ginseng-hydrolyzing bacteria [Ginseng-hydrolyzing bacteria colonized (GBC) mice]. The hydrolyzing potential was related to the number of anaerobes, especially Bacteroides/Prevotella. GBC mice were established by 6-generation inbreeding under control of hydrolyzing potential. The male mice were administered 1, 2-dimethylhydrazine (DMH) and either Ginseng or M1 orally. DMH treatment induced aberrant crypts (AC) in the colorecta of all control mice 7 weeks after initial treatment, whereas Ginseng treatment decreased the number of AC by 43% (p <0.02). Fifteen weeks later, AC counts in the control mice became more than double and all mice had colon carcinomas. In contrast, M1 given AC bearing mice prevented tumorigenesis of AC by 80% (p < 0.03). The amount of M1 in the colorecta was sufficient for inhibition of tumor growth in vitro. These results suggest that intestinal bacteria hydrolyze Ginseng to an anticarcinogen, rendering the mice resistant to the carcinogen.