Abstract: AIM: To observe the in vitro effects of Agrimoni Pilosa aqueous extract on platelet aggregation, coagulation function and hemorheology, and to explore its related mechanisms of action on hemostatic and coagulation function. METHODS: Platelet rich plasma (PRP) and platelet poor plasma (PPP) from volunteers were mixed with 0, 4 , 20 and 80 g/L Agrimoni Pilosa aqueous extract. The maximal platelet aggregation rate (PAR) of PRP induced by adenosine diphosphate (ADP) with platelet aggregation analyzer, expression levels of P-selection and fibrinogen receptor (Fg-R) were detemined by Flow cytometry. Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen (Fg) of PPP were detected with blood coagulation analyzer, respectively, blood cloting time (CT) and plasma ionized calcium (Ca²⁺) were detected with manual method and blood-gas analyzer, respectively, coagulable factor VII, VIII, IX and XI were detected by poor factor plasma correcting test. Blood viscosity, plasma viscosity and index of red cell aggregation were measured with hemorheology analyzer. RESULTS: At 4 g/L group, PAR, Fg-R and P-selectin expression levels were significantly lower than those at 0 g/L group (R<0.01). There was negative correlation between extract dose and any one of PAR, Fg-R and P-selectin level, but positive correlation between extract dose and inhibitory rate of platelet aggregation (R<0.01). At 4 g/L group, APTT, CT and FVII levels were remarkably higher , but PT, FVIII, FIX and FXI levels were lower, than those at 0 g/L group (R<0.01). APTT, CT and FVII levels showed positive correlation, but PT, FVIII, FIX and FXI levels showed negative correlation with extract dose (R<0.01). At 4 g/L group, levels of blood viscosity (1 s^-1 and 200 s^-1), plasma viscosity and index of red cell aggregation were markedly higher than those at 0 g/L group (R<0.01). They all indicated positive correlation with extract dose (R<0.01).CONCLUSION: Agrimoni Pilosa aqueous extract has anticoagulation efficacy mainly via platelet aggregation and coagulation function inhibition caused by inhibition of platelet Fg-R activation, secretion reaction and blood coagulable factors of intrinsic pathway, respectively. The extract is able to promote blood coagulating via activating blood coagulable factors of extrinsic pathway and increasing blood viscosity.

Key words: Agrimoni Pilosa, Platelet aggregation, Coagulation function, Hemorheology, Receptor, Fibrinogen, Coagulable factors