Resveratrol and vitamin C as antioxidants in blood platelets

We investigated the effects of two different compounds with potential antioxidative action (found in many fruits, which can be used in therapy of cardiovascular disorders): trans-resveratrol (3,4',5-trihydroxystilbene) and vitamin C on oxidative stress in blood platelets. Oxidative stress in blood platelets was estimated by the measurement of: (1) the generation of superoxide radicals (O(2)(-*)) (reduction of cytochrome c) and other reactive oxygen species--ROS: H(2)O(2), singlet oxygen and organic radicals (chemiluminescence), (2) the production of thiobarbituric acid reactive substances (TBARS) and the level of conjugate dienes as markers of lipid peroxidation. We have shown that vitamin C at the concentrations of 750-3000 microM, but not at the concentration of 100 microM (prooxidative action) significantly inhibited peroxidation of lipids (measured by TBARS and conjugate dienes) and the production of ROS in blood platelets. After the incubation of blood platelets for 30 min at 37 degrees C with vitamin C at the concentration of 3000 microM, inhibition of ROS generation (above 90%) was achieved. The inhibition of ROS production caused by resveratrol at physiological plasma concentrations 0.05-2 microM was lower than by vitamin C. At the highest concentration of vitamin C used (3000 microM), the inhibition of O(2)(-*) generation was about 40%. Moreover, we did not observe any synergistic action of resveratrol and vitamin C at antioxidative dose (3000 microM) on the inhibition of lipid peroxidation and the production of O(2)(-*) or ROS in blood platelets. Resveratrol as an antioxidant reduced oxidative stress in blood platelets caused by vitamin C at prooxidative dose (100 microM).