Antioxidant Effects and Drug Interactions of Resveratrol Present in Wine

Resveratrol is a phytoalexin found in grapes. Epidemiological and experimental studies suggest that the consumption of wine, particularly red wine, reduces the incidence and morbidity from coronary heart diseases. People using cardiovascular drugs may also consume red wine containing resveratrol for reducing the risk of disease. Thus, a potential interaction of resveratrol with the drugs is possible. Antioxidant activity of resveratrol was compared with vitamin E. IC₅₀ values for resveratrol and vitamin E were 1.5 × 10⁻⁵M and 1 × 10⁻³ M (NADPH-induced) and 1.5 × 10⁻⁴ M, 1 × 10⁻³ M (Ascorbate-induced), respectively. These results indicate that resveratrol has higher antioxidant effects than vitamin E. Nifedipine (antihypertensive), niacin (antilipemic) or lovastatin (antilipemic) were co-administered with a high dosage of resveratrol. Resveratrol pretreatment caused a 65% decrease in the concentration of nifedipine in both one hour and one week experiments. Niacin level in blood increased 20% in the presence of resveratrol at one hour and one week experiment. Lovastatin decreased 35% and 14.6% in both one hour experiment and one week experiment, respectively. The effects of resveratrol on rat liver microsomal drug metabolizing enzymes were also investigated. Resveratrol caused a 22% decrease in cytochrome P450 3A in enzyme activity. This decrease may explain increased niacin levels, but not the nifedipine and lovastatin. Nifedipine and lovastatin may be metabolized by different cytochrome P450 enzyme systems. High dosage of resveratrol (or products containing it) should be used with caution while other drugs are taken.