[Role of free radicals in blood platelet activation]

Free radicals and reactive oxygen containing substances are in addition to negative effects on biological systems important as signal molecules. Influencing their concentration by the action of antioxidants has a basic influence on the course of a number of cellular responses. The function of platelets is modulated in a significant way by the presence of vitamin E and resveratrol. The objective of the submitted paper is to assess the effect of Trolox (a stable analogue of vitamin E) and resveratrol sorbed by platelets on the aggregation response of washed platelets activated by collagen.

To investigate the effects of the mentioned antioxidants on platelet aggregation washed platelets were prepared. The concentrations of the two antioxidants sorbed by platelets were assessed by the method of high performance liquid chromatography. From the total Trolox concentration (4200 microM) the platelets sorbed 33.5 nmol/10(9) platelets and from the total concentration of resveratrol (300 microM) the platelets sorbed 6.5 nmol/10(9) platelets. Inhibited aggregation by collagen was 57% for Trolox and 98% for resveratrol.

The antioxidant capacity of both antioxidants is identical. The resveratrol concentration in platelets which led to almost complete inhibition of platelet aggregation by collagen was five times lower than for Trolox which caused a 57% inhibition of aggregation. Thus also other factors participate in the antioxidant activity of resveratrol. One of these factors is very probably the effect on arachidonic acid cycle.