Antiplatelet Effects of <i>Taraxacum mongolicum</i> Ethanol Extract through Modulation of Collagen-dependent Platelet Activation

Upon endothelial disruption, platelets rapidly adhere to exposed extracellular matrix proteins such as collagen and von Willebrand factor, undergo morphological changes, become activated by various soluble and insoluble agonists, and aggregate to form a hemostatic plug that sealsObjectives: Platelet activation is essential for hemostasis but contributes to pathological thrombosis when dysregulated.Taraxacum mongolicum Hand.-Mazz. is a traditional medicinal herb, yet its effects on platelet function remain incompletely understood.This study aimed to investigate the antiplatelet effects of a 70% T. mongolicum ethanol extract (TME) and its underlying mechanisms using human washed platelets.Methods: Human washed platelets were stimulated with collagen or thrombin.Platelet aggregation, dense granule secretion (adenosine triphosphate [ATP] and serotonin), thromboxane A 2 (TXA 2 ) production, clot retraction, and coagulation parameters (prothrombin time and activated partial thromboplastin time) were evaluated.Platelet cytotoxicity was assessed by lactate dehydrogenase release, and intracellular signaling pathways were analyzed by Western blotting.Results: TME preferentially inhibited collagen-induced platelet aggregation compared with thrombin-induced aggregation.Collagen-induced release of ATP, serotonin, and TXA 2 was significantly suppressed by TME.In addition, TME delayed thrombininduced clot retraction without affecting coagulation parameters or platelet viability.At the signaling level, TME modulated Akt and p38 MAPK phosphorylation and increased vasodilator-stimulated phosphoprotein phosphorylation at Ser157, suggesting attenuation of cytoskeletal remodeling and integrin IIb3-dependent contractile signaling. Conclusion:These results indicate that TME preferentially affects collagen-induced platelet activation and amplification processes.Collectively, the findings support the potential antiplatelet activity of TME and warrant further in vivo investigations.