Inhibition of microsomal lipid peroxidation by baicalein: a possible formation of an iron-baicalein complex.

Baicalein decreased the production of thiobarbituric acid reactive substances, the rate of oxygen consumption and iron reduction in the reaction system of ascorbic acid with FeCl3. Superoxide dismutase, catalase and hydroxyl radical scavengers had no significant effect. Iron-chelators had an inhibitory effect similar to that of baicalein. The production of thiobarbituric acid reactive substances of baicalein-treated microsomes obtained by centrifugation after incubation with baicalein was not observed in the reaction system, but was stimulated by adding iron with increases in concentration. The amount of bound iron to microsomal membranes increased by increasing both the concentration of baicalein and iron. The amount of baicalein bound to microsomal membranes increased with increasing concentration of added baicalein. These results suggest that baicalein bound to microsomal membranes inhibits lipid peroxidation by formating an iron-baicalein complex.