Résumé
ABSTRACT Essential oils are pharmacologically active and unexplored compounds. The inhibitory properties of essential oils from Baccharis dracunculifolia, Conyza bonariensis, Tithonia diversifolia and Ambrosia polystachya were evaluated in the coagulation and fibrinogenolysis induced by snake venoms. The essential oil from Conyza bonariensis extended the clotting time of Lachesis muta from 52.2 to 115.2 seconds and that of Bothrops moojeni from 108.3 to 2340.0 seconds, when pre-incubated with the venoms. The longest clotting times for Bothrops atrox venom were observed after incubation with the essential oils from Conyza bonariensis and Tithonia diversifolia: the times increased from 100.8 to 264.0 and 227.7 seconds, respectively. The prior incubation of the essential oils with plasma and subsequent addition of Lachesis muta venom resulted in a pro-clotting effect. The oils from Ambrosia polystachya and Baccharis dracunculifolia caused 100% of inhibition on the fibrinogenolysis induced by Bothrops moojeni and Lachesis muta venoms (the oils were previously incubated with the venom). The results indicate that the essential oils show promise as adjuvants for the treatment of snakebites.