Antinociceptive effect of Aristolochia trilobata stem essential oil and 6-methyl-5-hepten-2-yl acetate, its main compound, in rodents

Abstract

Aristolochia trilobata L. is an aromatic plant, popularly known as „mil-homens?, and its essential oil is generally used to treat colic, diarrhea, and dysentery disorders. We evaluated the antinociceptive effect of A. trilobata stem essential oil (EO) and of its major compound, the (R)-(-)-6-methyl-5-hepten-2-yl acetate (sulcatyl acetate: SA), using acetic acid (0.65%)-induced writhing response and formalin -induced (20 µl of 2,5%) nociceptive behavior in mice. We also evaluated the EO and SA effect on motor coordination, using the rota-rod apparatus. EO (25, 50 and 100 mg/kg) or SA (25 and 50 mg/kg) reduced nociceptive behavior in the writhing test (p < 0.001). EO (100 mg/kg) and SA (25 and 50 mg/kg) decreased the nociception on first phase of formalin test (p < 0.05). On second phase, EO(25: p < 0.01; 50: p < 0.05 and 100 mg/kg: p < 0.001) and SA (25 and 50 mg/kg; p < 0.001) reduced the nociceptive response induced by formalin. EO and SA were not able to cause changes in the motor coordination of animals. Together, our results suggest that the EO has an analgesic profile and SA seems to be one of the active compounds in this effect