Lipoprotein oxidation mediated by J774 murine macrophages is inhibited by individual red wine polyphenols but not by ethanol.

The in vitro capacities of individual polyphenols in red wine to inhibit the cell-mediated oxidation of lipoproteins and their effects on cell viability were determined. LDL and HDL were incubated with J774.A1 macrophages and 2 and 4 micro mol/L copper, respectively, in the absence and presence of polyphenols in ethanol at concentrations found in red wine. A mixture of polyphenols in amounts found in red wine equivalent to 0.2 g/L ethanol and 0.05 g/L ethanol inhibited thiobarbituric acid-reactive substance production from LDL by 91.7 and 45.9%, respectively, compared with ethanol controls (P < 0.01). HDL oxidation was inhibited 85 and 82.4% by the polyphenols at 0.2 and 0.05 g/L ethanol (P < 0.01). The effects of the polyphenol mixture on LDL oxidation were confirmed by measuring production of conjugated dienes and lipid peroxides, and trinitrobenzene sulfonic acid reactivity. Catechin at the concentration found in red wine (1.32 micro mol/L) at an ethanol concentration equivalent to 0.2 g/L inhibited LDL oxidation by 83.2%, while epicatechin (0.56 micro mol/L) and gallic acid (1.02 micro mol/L) inhibited by 60.6 and 26.9%, respectively (P < 0.05). At 1 micro mol/L, LDL oxidation was inhibited by epicatechin, catechin and quercetin by 86.2, 79.9 and 69.4%, respectively (P < 0.05). Incubation of macrophages with ethanol alone and with polyphenols in ethanol did not affect cell viability. Our results indicate that catechin and epicatechin are the major contributors to the antioxidant activity of red wine.