Antagonistic Effect and Mechanism of a New Derivative of Gingkolide B on Platelet Aggregation

AimTo study antagonistic effect and mechanism of a new derivative of ginkolide B named XQ on platelet aggregation.MethodsTo assay inhibiting effect of XQ on PAF-induced platelet aggregation with turbidimetry method, rabbits were administered at different final concentrations via iv at different times. The specific binding of [3H]PAF to rabbit platelet receptor was investigated by radio ligand binding assay (RLBA).ResultsThree groups (1.95, 3.9, 7.8 mg·kg−1) had significant effect on inhibiting PAF-induced platelet aggregation in rabbits, and inhibition ratio were 29.8%, 43.5% and 55.2% respectively (compared to normal group, P<0.01) The equilibrium dissociation constant (KD) and maximum binding capacity of [3H]PAF were 8.31×10−5 mmol·L−1 and 2.62×10−9 mmol/108 platelets respectively. Something about XQ and GB's specific binding inhibition was found that the Ki of XQ and GB were 8.72×10−8 and 7.13×10−7 mol·L−1 respectively.ConclusionXQ can inhibit platelet aggregation by competitively occupying specific PAF receptor site on blood platelet membrane.