Evaluation of antilipid peroxidative action of propolis ethanol extract

The antilipid peroxidative action of the ethanol extract of Brazilian propolis at a concentration of 47% (w/v) was evaluated by examining the inhibitory effect of the extract on the formation of hydroperoxide- and endoperoxide-type lipid peroxides during heating of authentic polyunsaturated fatty acids and on Fe(3+)-ADP/ascorbic acid- and Fe(3+)-ADP/NADPH-dependent lipid peroxidation reactions in rat liver microsomes. Hydroperoxide-type lipid peroxides were measured by the haemoglobin-methylene blue method and endoperoxide-type lipid peroxides by the thiobarbituric acid (TBA), Fe(3+)-TBA and LPO-586 methods. Propolis ethanol extract inhibited dose-dependently the formation of hydroperoxide- and endoperoxide-type lipid peroxides during heating of linoleic acid, linolenic acid or arachidonic acid and the amount of the extract causing a half inhibition of these lipid peroxide formations ranged between 20 and 75 microg. Propolis ethanol extract inhibited dose-dependently both Fe(3+)-ADP/ascorbic acid- and Fe(3+)-ADP/NADPH-dependent lipid peroxidation reactions in rat liver microsomes when lipid peroxides produced in both reactions were measured by the TBA method. The amount of propolis extract causing a half inhibition of the Fe(3+)-ADP/ascorbic acid-dependent lipid peroxidation was about 5 microg, while that of the extract causing a half inhibition of the Fe(3+)-ADP/NADPH-dependent lipid peroxidation was about 0.15 microg. These results indicate that the propolis ethanol extract exerts an antilipid peroxidative action at very low doses.