FROM:
Biochem Mol Biol Int 1998 (Dec); 46 (6): 1243–1248
Akiba S, Kawauchi T, Oka T, Hashizume T, Sato T
Department of Pathological Biochemistry,
Kyoto Pharmaceutical University, Japan
The effect of the leaf extract of Ginkgo biloba
L. on platelet aggregation induced by oxidative stress was
studied. The extract caused a dose–dependent inhibition of
platelet aggregation stimulated with tert-butyl
hydroperoxide (t-BHP) and Fe2+. Similar inhibitory activity
was observed when platelets were exposed to H2O2 and Fe2+.
Synergistic aggregation induced by a combination of t-BHP
and Fe2+ or H2O2 and Fe2+ in association with suboptimal
concentration of collagen or U46619, was prevented by the
extract. However, the extract failed to inhibit aggregation
in response to collagen, thrombin or U46619. Ginkgolides A,
B and C inhibited platelet-activating factor-induced
aggregation, but not oxidant–induced aggregation. These data
suggest that the suppressive effect of the extract is
specific on platelet aggregation stimulated by oxidative
stress, and that this effect is involved in the mechanism
related to its protective effect upon cerebral or myocardial
injuries.