The anticoagulant and antithrombotic profile of a root methanolic extract from Strophioblachia fimbricalyx Boerl (Euphorbiaceae)
Cardiovascular diseases, especially thrombosis, represent one of the most serioust worldwide causes of morbidity and death  and at the same time the current therapy with anticoagulant and/or antiplatelet drugs presents several side effects . In the course of our investigation on bioactive compounds from the plants of the family Euphorbiaceae, we have evaluated the anticoagulant activity of the methanol extract of the roots of Strophioblachia fimbricalyx, collected in Thailand. Though this plant was previously investigated for its constituents , nothing has been done on its biological and pharmacological activities. The water soluble fraction of this extract was found to exhibit the anticoagulant activity (4.3mg/mL) in the intrinsic pathway (aPTT), with an increase in clotting time about three folds. Interestingly, this fraction was not active either in the PT (5.1mg/mL) or toward the platelet aggregation (induced by ADP). Furthermore, using a thrombosis model which combines stasis and hyper-coagulability in rats , it was found that this fraction was able to inhibit the thrombus formation in a dose-dependent manner. Intravenous administration of this fraction (10, 25 and 50mg/Kg), five minutes prior to thromboplastin administration, was found to decrease thrombus weight by 10.9%, 72.6% and 88.5%, respectively. To the best of our knowledge this is the first report on the in vitro anticoagulant and in vivo antithrombotic activities of S. fimbricalyx. Isolation and characterization of the constituents of S. fimbricalyx, as well as the application of nanoparticles to improve the in vivo activity of the extract and compounds are underway.
Acknowledgements: We thank FCT, CIIMAR Plurianual and CEQOFFUP/CEQUIMED and POCTI of Portugal and CNPq (Brazil) for support.
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