PRINCIPAL PHENOLIC PHYTOCHEMICALS IN SELECTED CALIFORNIA WINES AND THEIR ANTIOXIDANT ACTIVITY IN INHIBITING OXIDATION OF HUMAN LOW-DENSITY LIPOPROTEINS

The phenolic antioxidant phytochemicals in wines have been implicated for the lower rates of cardiac disease mortality among people drinking wine regularly in certain European populations. The activities of 20 selected California wines in inhibiting the copper-catalyzed oxidation of human low-density lipoproteins (LDL) were determined. This antioxidant activity was related to the major phenolic compounds and not to resveratrol analyzed in wines by HPLC and GC-MS. The relative inhibition of LDL oxidation varied from 46 to 100% with the red wines and from 3 to 6% with the white wines. When compared at the same total phenol concentration, the inhibition of LDL oxidation varied from 37 to 65% with the red wines and from 27 to 46% with the white wines. The relative antioxidant activity correlated with total phenol contents of wines (r = 0.94) and with the concentrations of gallic acid (r = 0.92), catechin (r = 0.76), myricetin (r = 0.70), quercetin (r = 0.68), caffeic acid (r = 0.63), rutin (r = 0.50), epicatechin (r = 0.45), cyanidin (r = 0.43), and malvidin 3-glucoside (r = 0.38). Therefore, the activity of wines to protect LDL from oxidation appeared to be distributed widely among the principal phenolic compounds.