Chemical composition and antinociceptive effects of essential oil from aerial parts of gundelia tournefortii L asteraceae (Compositae) in rats

Abstract

Purpose: To investigate the antinociceptive effect of the essential oil from the aerial parts of Gundelia. tournefortii (EOGT) in various experimental models Methods: The essential oil from the aerial parts of Gundelia tournefortii was extracted using steam distillation method median lethal dose (LD50) of EOGT was evaluated using the method of Lorke. Antinociceptive effect of EOGT in rats was carried out using chemical (formalin and acetic acid) and thermal (hot-plate) nociceptive tests at doses of 10, 31.6, 100, 316 and 1000 mg/kg. The possible mechanism of action of EOGT was also examined. Results: In acute toxicity test, LD50 for EOGT was 2500 mg/kg. EOGT at test doses (10, 31.6, 100, 316 and 1000 mg/kg, orally) significantly reduced pain response in all tests in a dose-dependent manner (p < 0.05). Glibenclamide (potassium channel sensitive to ATP antagonist) and yoimbina (α2 adrenergic receptor antagonist), partially antagonized the antinociceptive activity induced by EOGT. However, naloxone (opioid antagonist) and L-NAME (an inhibitor of nitric oxide synthase) did not reverse the antinociception produced by EOGT. Conclusion: Essential oil from the aerial parts of G. tournefortii shows significant antinociceptive activity, which appeared to involve the participation of K+ channels sensitive to ATP and adrenergic receptors. These findings justify in part the traditional use of the plant in the treatment of various painful conditions.