Influences of flavonoids on erythrocyte membrane and metabolic implication through anionic exchange modulation.

The antioxidative activity of some natural flavonoids was analyzed against the stable free radical 2,2- diphenyl-1-picryhydrazyl. The results indicate that the scavenging power of the tested flavonols is higher than that of the synthetic antioxidants butylated hydroxyanisole and butylated hydroxytoluene; instead, the flavanones show little activity, as indicated by efficient concentration (EC50) values. Flavonoid autoxidation and interaction with Fe2? and hydrogen peroxide were tested using erythrocyte membranes as a model. The results show that some compounds, like hesperetin, evidence a pro-oxidant activity higher than the ascorbic acid/iron reference system. Thecompounds with strong oxidative capability do not only influence cellular redox balance but also activate caspase- 3, producing lactate dehydrogenase release and enhancing anionic exchange at the level of band 3 protein.