ZHI MU SAPOGENIN IS A POWERFUL INHIBITOR OF Na~+、K~+-ATPase
摘要
Zhi Mu (Anemarrhena asphedoloies Bgo) is a Chinese herb used as an‘antipyretic’agentin Chinese traditional medicine,but its mechanism of action is notclear yet.It has been reported that the biosynthesis of Na~+、K~+-ATPase is induced bythyroxin and the elevated oxygen uptake in‘hyperthyroidic’animals is the result ofincrease of this enzyme.It is also said that the energy produced at basal metabolicstate is mainly to support the normal function of Na~+、K~+-ATPase,and may reach40～60% of the total energy consumption of the body.Zhi Mu was therefore examined to see whether it may act as a potent Na~+,K~+-ATPase inhibitor.We have obtained a saponin and its hydrolytic product,a sapogenin from ZhiMu.The saponin,sapogenin and its hemisuccinyl derivative all show a potentinhibitory action on Na~+、K~+-ATPase,and reduces the oxygen uptake of thyroxininduced liver slices.The inhibitory action of the succinyl derivative is even morepotent than the well-known inhibitor-ouabain.The melting point,infra-red spectrum,mass spectrum and TLC behaviour of ZhiMu sapogenin match well with the known values for the compound sarsasapogenin.