Hemostatic Effect of 20(S)-Panaxadiol by Induced Platelet Aggregation Depending on Calcium Signaling Pathway

Panax notoginseng (Burk.) F.H. Chen is the most traditional hemostatic herb in China. Our previous research found that 20(S)-protopanaxadiol showed the hemostatic effect. And 20(S)-panaxadiol (PD) has a similar structure to 20(S)-protopanaxadiol with a dammarane skeleton. So, this article mainly studies the hemostatic effect of PD. The mouse tail amputation and liver scratch models were used to detect the hemostatic effect of PD. Blood routine and plasma coagulation parameters were measured by using a blood analyzer. The platelet aggregometer analyzed the platelet aggregation rate and adenosine triphosphate (ATP) concentration. Moreover, the intracellular calcium concentration ([Ca²⁺] _i ), P-Selectin (CD62P), PAC-1 (GP IIb/IIIa receptor marker), and cyclic adenosine monophosphate (cAMP) of platelets were also detected. The results showed that PD obviously shortened the bleeding time of the model mouse, affected the RBC and PLT parameters of rats, reduced APTT and TT, elevated FIB concentration, and promoted human/rat-washed platelet aggregation in vitro. PD promoted the release of ATP and [Ca²⁺] _i and slightly increased the expression of CD62P and PAC-1 of platelets without 1 mM Ca²⁺. After adding 1 mM Ca²⁺, PD obviously increased ATP releasing and CD62P and GP IIb/IIIa expression rate and decreased the cAMP level of platelets. These parameter changes of PD-caused platelet were inhibited by vorapaxar. Besides, PD increased the phosphorylation of phosphoinositide 3-kinase/protein kinase B/glycogen synthase kinase 3β (PI3K/Akt/GSK3β) of human platelets. PD is an important hemostatic ingredient in Panax notoginseng, which induced platelet aggregation by affecting the calcium signaling and activating the PI3K/Akt/GSK3β signaling pathway.