Inhibition of human renin activity by saponins.

Renin is the most important enzyme in the renin-angiotensin system. Our previous study led to the identification of soyasaponin I, the first renin inhibitor isolated from soybean. In the present study, the effects of saponins and sapogenols on human renin activities were investigated. Soyasaponins I and II, glycyrrhizin, monoglucuronyl glycyrrhetic acid (MGGA), chikusetsusaponin IV, and Kochia scoparia fruit saponins (momordins) were found to inhibit renin activity. On the other hand, sapogenols (soyasapogenol B and glycyrrhetic acid), saikosaponins b2 and c, and ginsenoside Rb(1) had no effect on renin activity. These results clearly indicate that the 3-O-beta-dglucopyranosiduronic moiety in saponins (glucuronide saponin) is essential for renin inhibition.