Pharmacologyonline 1: 217-228 (2009) Shahriyary and Yazdanparast

The present study focused on evaluating the effects of a methanol crude extract of Artemisia dracunculus (tarragon) leaves on human platelet function in vitro and several markers of platelet coagulation, including the prothrombin time (PT), the activated partial thrombin time (APTT) and bleeding time (BT) using wistar rats and mice for in vivo pulmonary thrombosis. Human platelets were incubated with different concentrations of the test extract and then activated with thrombin. Adhesion, aggregation and spreading to the laminin-coated plates were evaluated by scanning electron microscopy (SEM). In the control samples, most of the adhered platelets showed extensive spreading on laminincoated plates. Pretreatment of platelets with the plant extract had inhibitory effect on the secretion of adenine nucleotides and malonldialdehyde (MDA) formation. On the other hand, oral administration of the extract protected the mice against thrombotic death or paralysis induced by collagen and epinephrine in a dose-dependent manner. In addition, the extract had significant effects on the coagulation parameters. Mouse tail bleeding time was significantly prolonged among the treated mice. Our results showed that the methanol crude extract of tarragon has anticoagulant and antithrombotic activity. These findings provide scientific basis for traditional use of tarragon for treatment of thrombotic diseases.