Anthocyanins (Red Grape Skin Extract)

Consumption of red wine with meals reduces the susceptibility of human plasma and low-density lipoprotein to lipid peroxidation

Fuhrman B., Lavy A., Aviram M. Am J Clin Nutr 1995;61:549-554

The effect of consumption of red or white wine (11% alcohol) with meals on the propensity of plasma and low-density lipoprotein (LDL) to undergo lipid peroxidation was studied in 17 healthy men who were divided into two groups: 8 received 400 mL red wine/d for 2 wk, and 9 received a similar amount of white wine. Red wine consumption for 2 wk resulted in a 20% reduction in the propensity of plasma to undergo lipid peroxidation (in the presence of a free-radical-generating system) as determined by the thiobarbituric acid reactive substances (TBARS) assay. In parallel, red wine consumption reduced the propensity of the volunteers' LDL to undergo lipid peroxidation (in response to copper ions) as determined by a 46%, 72%, and 54% decrease in the content of TBARS, lipid peroxides, and conjugated dienes in LDL, respectively, as well as by a substantial prolongation of the lag phase required for the initiation of LDL oxidation. On the contrary, dietary consumption of white wine for 2 wk resulted in a 34% increase in plasma's propensity to undergo lipid peroxidation and also in a 41% increased propensity of the LDL to undergo lipid peroxidation. The antioxidant effect of dietary red wine on plasma lipid peroxidation was not secondary to changes in the plasma vitamin E or beta-carotene content but could be related to the elevation of polyphenol concentration in plasma and LDL. Thus, some phenolic substances that exist in red wine, but not in white wine, are absorbed, bind to plasma LDL, and may be responsible for the antioxidant properties of red wine.
 

Principal phenolic phytochemicals in selected California wines and their antioxidant activity in inhibiting oxidation of human low-density lipoproteins

Frankel E.N., Waterhouse A.L., Teissedre P.L. J Agric Food Chem 1995;43:890-894

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.