EFFECT OF QUERCETIN ON MEMBRANE-LINKED ACTIVITIES

The flavonoid quercetin inhibited the Mg++-dependent, Na+ and K+ stimulated ATPase.† The effect was dependent on the concentration of Na+ and K+. Quercetin, like other known inhibitors which act on both transport ATPase and oxidative phosphorylation, inhibited the mitochondrial ATPase activity. Mitochondrial electron transport was also affected. Sulfhydryl compounds partially reversed the effect of quercetin on ATPase activities and completely eliminated that on electron transport. It is concluded that quercetin shows affinity for membrane-dependent cellular activities. © 1969.