Summary
The effects of catechins were studied in both unstimulated platelets and platelets
submitted to a mild oxidative stress induced by docosa-hexaenoic acid (DHA). Human
unstimulated platelets were incubated in the presence of catechin or epicatechin (1,
10 or 100 μM) for 2 h at 37° C. Treatment by 1 μM epicatechin was sufficient to induce
a significant inhibition (-30%) of basal thromboxane B2 formation. This result is consistent with the observed inhibitory effects of flavonoids
on platelet aggregation. DHA treatment of platelets decreased the amount of a-tocopherol
and increased the malondialdehyde (MDA) formation. The presence of epicatechin or
catechin prevented the oxidative stress induced by DHA. Indeed, the platelet a-tocopherol
level was significantly increased when compared to that of platelets treated by DHA
alone, to reach the control level, whereas MDA was depressed to a level even lower
than the control one. Our results indicate that catechin and especially epicatechin
protect platelets from a peroxidative stress.
