Metabolism of kalopanaxsaponin B and H by human intestinal bacteria and antidiabetic activity of their metabolites.

To investigate the relationship between the intestinal bacterial metabolism of kalopanaxsaponin B and H from Kalopanax pictus (Araliaceae), and their antidiabetic effect, kalopanaxsaponin B and H were metabolized by human intestinal microflora and the antidiabetic activity of their metabolites was measured. Human intestinal microflora metabolized kalopanaxsaponin B to kalopanaxsaponin A, hederagenin 3-O-alpha-L-arabinopyranoside and hederagenin. The main metabolites of kalopanaxsaponin B were kalopanaxsaponin A and hederagenin. Kalopanaxsaponin H was metabolized to kalopanaxsaponin A and I, hederagenin 3-O-alpha-L-arabinopyranoside and hederagenin. The main metabolites of kalopanaxsaponin H were kalopanaxsaponin I and hederagenin. Among kalopanaxsaponin B, H and their metabolites, kalopanaxsaponin A showed the most potent antidiabetic activity, followed by hederagenin. However, the main components, kalopanaxsaponin B and H, in K. pictus were inactive.