THE STRUCTURE ACTIVITY RELATIONSHIP OF SAIKOSAPONINS AND GLYCYRRHIZIN DERIVATIVES FOR Na⁺, K⁺-ATPase INHIBITING ACTION

The study on structure activity relationship of saikosaponins and glycyrrhizin derivatives for Na⁺,K⁺-ATP ase inhibiting action has been made in vitro . The results showed that the order of potency of inhibitory effect of saikosaponins on Na⁺,K⁺-ATPase is as follows: b₁>d>b₂>b₄>a>b₃>e>c. The chemical structure C₂₃-OH, C₁₆-OH and the C₁₁, C₁₃ conjugated double diene of saikosaponins are important for its inhibitory activity. The inhibitory potency of glycyrrhizin(GL), glycyrrhetinic acid(GA) and carbenoxolone(CX) for Na⁺, K⁺-ATPase activity is as follows: GA≥CX>GL. In addition, the inhibitory effect of saikosaponin d on Na⁺, K⁺-ATPase was found to be non competitive.