Comparative studies on the antioxidant properties of cholesteryl esters of substituted cinnamic acids in model conditions

Five cholesteryl esters of methoxy cinnamic acid derivatives, which can be used as potential inhibitors of lipids oxidation, have different antioxidant activity as measured by chemiluminescence method. The rate constants of inhibition (k(In) (H)) were determined in a model reaction of an initiated oxidation of tetraline at 353 K. The chemiluminescence results characterize the compounds studied as relatively good antioxidants in tetraline oxidation. The presence of one or two methoxy groups in ortho-position towards the hydroxyl group in the aromatic fragment has no substantial effect on the antioxidant efficiency, mainly due to steric hindrances.