Planta medica
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The antimetastatic effects of orally administered ginsenoside Rb1 (Rb1) and an active metabolite by intestinal bacteria, 20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol (I), were studied, by using a spontaneous metastasis model produced by subcutaneous injection of Lewis lung carcinoma (LLC) in syngeneic C57BL/6 mice. A thorough analysis of the hydrolyzing potential (transformation by intestinal bacteria) was first done and the data found were positively correlated to the antimetastatic effect of Rb1 through the medium of I. ⋯ In a leg amputation model with the LLC-line, an effect on survival time of I (8 mg/kg/day) equal to that of 5-FU (10 mg/kg/day) was seen and 38% mice were cured as compared with 13% cured by amputation alone. These findings suggest that the active drug is the bacterial metabolite I which should be administered rather than Rb1.