Antiplatelet and antithrombotic effects of cordycepin-enriched WIB-801CE from Cordyceps militaris ex vivo, in vivo, and in vitro

Background A species of the fungal genus Cordyceps has been used as a complementary and alternative medicine of traditional Chinese medicine, and its major component cordycepin and cordycepin-enriched WIB-801CE are known to have antiplatelet effects in vitro. However, it is unknown whether they have also endogenous antiplatelet and antithrombotic effects. In this study, to resolve these doubts, we prepared cordycepin-enriched WIB-801CE, an ethanol extract from Cordyceps militaris -hypha, then evaluated its ex vivo, in vivo, and in vitro antiplatelet and antithrombotic effects. Methods Ex vivo effects of WIB-801CE on collagen- and ADP-induced platelet aggregation, serotonin release, thromboxane A 2 (TXA 2 ) production and its associated activities of enzymes [cyclooxygenase-1 (COX-1), TXA 2 synthase (TXAS)], arachidonic acid (AA) release and its associated phosphorylation of phospholipase C β3 , phospholipase C γ2 or cytosolic phospholipase A 2 , mitogen-activated protein kinase (MAPK) [p 38 MAPK , extracellular signal-regulated kinase (ERK)], and blood coagulation time in rats were investigated. In vivo effects of WIB-801CE on collagen plus epinephrine-induced acute pulmonary thromboembolism, and tail bleeding time in mice were also inquired. In vitro effects of WIB-801CE on cytotoxicity, and fibrin clot retraction in human platelets, and nitric oxide (NO) production in RAW264.7 cells or free radical scavenging activity were studied. Results Cordycepin-enriched WIB-801CE inhibited ex vivo platelet aggregation, TXA 2 production, AA release, TXAS activity, serotonin release, and p 38 MAPK and ERK2 phosphorylation in collagen- and ADP-activated rat platelets without affecting blood coagulation. Furthermore, WIB-801CE manifested in vivo inhibitory effect on collagen plus epinephrine-induced pulmonary thromboembolism mice model. WIB-801CE inhibited in vitro NO production and fibrin clot retraction, but elevated free radical scavenging activity without affecting cytotoxicity against human platelets. Conclusion WIB-801CE inhibited collagen- and ADP-induced platelet activation and its associated thrombus formation ex vivo and in vivo. These were resulted from down-regulation of TXA 2 production and its related AA release and TXAS activity, and p 38 MAPK and ERK2 activation. These results suggest that WIB-801CE has therapeutic potential to treat platelet activation-mediated thrombotic diseases in vivo.