Inhibition ofIn Vitro Human LDL Oxidation by Phenolic Antioxidants from Grapes and Wines

Abstract

Current research suggests that wine contains substances that may reduce the mortality rate from coronary diseases. The oxidation of low-density lipoprotein (LDL) is thought to be a key step in the development of atherosclerosis. Phenolic fractions of a Petite Syrah wine were evaluated for their antioxidant activity in inhibiting LDL oxidation in vitro. The more active fractions contained components of the catechin family. The catechin oligomers and the procyanidin dimers (B2, B3, B4, B6, B8) and trimers (C1, C2) were extracted, isolated and purified from grapes seeds. These compounds were tested for their inhibition of LDL oxidation, along with other monomeric wine phenolics. The procyanidin dimers B2 and B8, and trimer C1, and the monomers catechin, epicatechin and myricetin had the highest antioxidant activity. The procyanidin dimers B3, B4 and C2 and the monomers gallic acid, quercetin, caffeic acid, and rutin, and a group of compounds that included the dimer B6, ellagic acid, sinapic acid, cyanidin had lower antioxidant activity and α-tocopherol had the least activity. Thus, the numerous phenolic compounds found in wine are potent antioxidants in inhibiting LDL oxidationin vitro.