title: Corticosterone secretion-inducing activity of saikosaponin metabolites formed in the alimentary tract.
abstract: The corticosterone secretion-inducing activities of saikosaponin a, saikosaponin c and saikosaponin d, isolated from the root of Bupleurum falcatum L., and 27 metabolites formed in the murine alimentary tract were studied in mice. Serum corticosterone was determined by high-performance liquid chromatography (HPLC). Intraperitoneal administration of saikosaponin a and its intestinal metabolite, prosaikogenin F, showed corticosterone secretion-inducing activity at a dose of 0.1 mmol/kg, and maximally increased it at a dose of 0.4 mmol/kg. On the other hand, the genuine sapogenin, saikogenin F, was inactive. Saikosaponin b1 and saikosaponin g, gastric metabolites of saikosaponin a, and their intestinal metabolites, prosaikogenin A, prosaikogenin H, saikogenin A and saikogenin H, were also inactive. Serum corticosterone was increased by the administration of saikosaponin d and its intestinal metabolite, prosaikogenin G, at a dose of 0.04 mmol/kg, and it reached the maximal level at the dose of 0.1 mmol/kg. Saikogenin G also showed a slight activity. A gastric metabolite of saikosaponin d, saikosaponin b2, and its intestinal metabolites, prosaikogenin D and saikogenin D, were inactive. In the experiments on saikosaponin c and its metabolites, saikosaponin c was inactive but its intestinal metabolites, especially prosaikogenin E-2, showed activity almost equal to that of saikosaponin a. Saikosaponin h and saikosaponin i, gastric metabolites of saikosaponin c, were also inactive, but their prosaikogenins showed slight activities. When these compounds were orally administered, their corticosterone secretion-inducing activities were similar to those obtained in the intraperitoneal experiment. These results suggest that a proper polar balance between the sugar moiety and the aglycone is important for the corticosterone secretion-inducing activity of saikosaponins and their metabolites.
authors.forename: M
authors.initials: M
authors.lastname: Nose
authors.forename: S
authors.initials: S
authors.lastname: Amagaya
authors.forename: Y
authors.initials: Y
authors.lastname: Ogihara
mesh_terms: D000818:Animals; D001711:Biotransformation; D003345:Corticosterone / Q000378:metabolism*; D004064:Digestive System / Q000378:metabolism*; D008297:Male; D051379:Mice; D009828:Oleanolic Acid / Q000031:analogs & derivatives*; D012502:Sapogenins / Q000378:metabolism / Q000494:pharmacology*; D012503:Saponins; D013268:Stimulation, Chemical
chemical_list: D012502:Sapogenins; D012503:Saponins; D009828:Oleanolic Acid; C025759:saikosaponin D; D003345:Corticosterone