INHIBITION OF IN-VITRO HUMAN LDL OXIDATION BY PHENOLIC ANTIOXIDANTS FROM GRAPES AND WINES

Current research suggests that wine contains substances that may reduc e the mortality rate from coronary diseases. The oxidation of low-dens ity lipoprotein (LDL) is thought to be a key step in the development o f atherosclerosis. Phenolic fractions of a Petite Syrah wine were eval uated for their antioxidant activity in inhibiting LDL oxidation in vi tro. The more active fractions contained components of the catechin fa mily. The catechin oligomers and the procyanidin dimers (B-2, B-3, B-4 , B,(6) B-8) and trimers (C-1, C-2) were extracted, isolated and purif ied from grapes seeds. These compounds were tested for their inhibitio n of LDL oxidation, along with other monomeric wine phenolics. The pro cyanidin dimers B-2 and B-8, and trimer C-1, and the monomers catechin , epicatechin and myricetin had the highest antioxidant activity. The procyanidin dimers B-3, B-4 and C-2 and the monomers gallic acid, quer cetin, caffeic acid, and rutin, and a group of compounds that included the dimer B-6, ellagic acid, sinapic acid, cyanidin had lower antioxi dant activity and alpha-tocopherol had the least activity. Thus, the n umerous phenolic compounds found in wine are potent antioxidants in in hibiting LDL oxidation in vitro.