Document Type : Short communication
Department of Pharmacology and Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran.
Background and objectives: Artemisia dracunculus (tarragon) essential oil has shown antinociceptive effect in some animal models. This study was aimed to find out its possible mechanism of action in formalin-induced pain behavior in mice. Methods: Essential oil of the plant was prepared by hydro-distillation method. Male Swiss mice (25–30 g) and formalin test were used in the pain model. First, the antinociceptive activity of three doses of A. dracunculus essential oil (50, 100 and 200 µL/kg) were examined and then the dose of 100 µL/kg was selected for mechanistic experiments. Different groups of mice (n=6) were pretreated with naloxone, prazocin, yohimbine, propranolol, ondansetron, cyproheptadine, sulpiride and haloperidol to evaluate contribution of opioid, adrenergic, serotoninergic and dopaminergic receptors in the essential oil effect. Besides arginine, N(G)-nitro-L-arginine methyl ester (L-NAME), methylene blue, tadalafil and glibenclamide were used to find out the possible involvement of nitric oxide pathway for the essential oil effect. Results: Artemisia dracunculus essential oil significantly (p<0.001) and in a dose-dependent manner demonstrated antinociception in both acute and chronic phases of the formalin test. Prazocin, yohimbine, propranolol, naloxone, ondansetron and sulpiride were ineffective in prevention of the induced antinociceptive effect. Cyproheptadine, arginine and tadalafil partially inhibited A. dracunculus essential oil antinociception while methylene blue and glibenclamide potentiated the effect. Conclusions: Artemisia dracunculus essential oil showed antinociceptive effect in formalin test and the observed effect was partially prevented by cyproheptadine, arginine and tadalafil indicating the possible role of serotoninergic and nitrergic pathways.