LIPOPHILIC DERIVATIVES OF CAFFEIC ACID AS LIPOXYGENASE INHIBITORS WITH ANTIOXIDANT PROPERTIES

We have prepared two lipophilic derivatives of caffeic acid at the carboxylic function - caffeic acid phenethyl ester, an active component of propolis, and N,N'-dicyclohexyl-O-(3,4-dihydroxycinnamoyl)-isourea. Both substances inhibit barley 5-lipoxygenase and soybean 15-lipoxygenase at micromolar concentrations. The inhibition is uncompetitive;dose-dependent and reversible. The caffeic acid derivatives also exhibit antioxidant properties and at a concentration 5 - 10 mu M completely block the production of the reactive oxygen species in human neutrophils and in the cell-free xanthine/xanthine oxidase system.