Inhibition of copper-induced lipid peroxidation by sinapic acid and its derivatives in correlation to their effect on the membrane structural properties.

The efficiencies of sinapic acid and its derivatives syringic acid, syringaldehyde, three sinapoyl esters (ethyl, propyl, butyl sinapates), 4-vinylsyringol and sinapine were investigated for prevention of lipid peroxidation in correlation with their interactions with model lipid membrane systems. Significant antioxidant activities of propyl and butyl sinapates were seen by fluorimetric assay in phosphatidylcholine liposomes as model membrane using C11-BODIPY lipophilic fluorescent probe. The sinapic acid esters also had the highest impact on membrane structural properties, as observed by differential scanning calorimetry and fluorescence polarisation measurements.