Principal phenolic phytochemicals in French Syrah and Grenache Rhone wines and their antioxidant activity in inhibiting oxidation of human low density lipoproteins

Abstract

<p style="text-align: justify;">Wine contains natural plant phenolic antioxidants that may protect circulating lipoproteins from oxidative damage. By inhibition of the copper-catalyzed oxidation of LDL we determined the activity of thirteen Rhône coast wines exclusively from Syrah and Grenache varieties. About 50 p. cent of the wines were made with a long maceration process. Major monomeric phenolic compounds and procyanidin dimers were analyzed in each sample by HPLC and correlated with relative LDL antioxidant activity. Correlations obtained can be grouped in 3 classes: catechin (r = 0.75), procyanidins, BI, B2, B3 (r = 0.43-0.55), malvidin-3-glucoside and cyanidin (r = 0.43), gallic acid, myreeitin, rutin (r = 0.2-0.4). On the same basis total phenol contents of wines gave a correlation with LDL antioxidant activity of r = 0.72. Comparison, at the same total phenol concentration, with different red California wines shows that antioxidant activity of French Syrah and Grenache range between that of Merlot (56-65 p. cent) and Cabernet Sauvignon (37-45 p.cent). In contrast Syrah wines made with a short extraction process gave lower inhibition of LDL oxidation of 16 p. cent which is less than white Califomia wines averaging 36 p. cent. Activity of each wine phenolic compound can play a role in protecting LDL against oxidation.</p>