METABOLISM OF SAIKOSAPONIN-C AND NARINGIN BY HUMAN INTESTINAL BACTERIA

By human intestinal bacteria, saikosaponin c was transformed to four m etabolites, prosaikogenin E1 (E1) prosaikogenin E2 (E2), prosaikogenin E3 (E3) and saikogenin E. Metabolic time course of saikosaponin c was as follows; in early time, saikosaponin c was converted to E1 and E2, and then these were transformed to saikogenin E via E3. Also, this me tabolic pathway was similar to the metabolism of saikosaponin c by rat intestinal bacteria. Bacteroides JY-6 and Bacteroides YK-4, the bacte ria isolated from human intestinal bacteria, could transform saikosapo nin c to E via E1 (or E2) and E3. However, these bacteria were not abl e to directly transform E1 and E2 to saikogenin E. Naringin was mainly transformed to naringenin by human intestinal bacteria. The minor met abolic pathway transformed naringin to naringenin via prunin. By JY-6 or YK-4, naringin was metabolized to naringenin only via prunin.