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.