Abstract: The antiplatelet effect of alcoholic extract of Piper hancei(PHE)was studied.It was shown that PHE inhibited rabbit platelet aggregation induced by platelet activating factor (PAF)and arachidonic acid(AA) either in vitro or ex vivo.The IC₅₀of PHE for PAF-induced platelet aggregation and for that of AA(in vitro)were 40.34 mg/L and 345.46 mg/L respectively.After iv of PHE (30 mg/kg),the maximum inhibitory rate for PAFinduced platelet aggregation and for that of AA(ex vivo)were 82.75% and 33.34% respectively;the duration of inhibitory effect for PAF-induced platelet aggregation and or that of AA were 60 min and 30 min respectively.PHE may exhibit certain selective anti-PAF activity.

Key words: Piper hancei Maxim, platelet activating factor, platelet aggregation