Antinociceptive activity of the essential oil from Artemisia ludoviciana

Ethnopharmacological relevance Aerial parts of Artemisia ludoviciana are widely used in Mexico for treating gastrointestinal disorders, painful complaints and diabetes. Aim of the study To establish the preclinical efficacy as antinociceptive agent of the essential oil (EO) from the aerial parts of A. ludoviciana using well-known animal models. Materials and methods Acute antinociceptive effect of EO (1, 10, 31.6, 100, and 316 mg/kg, i.p.) was evaluated using the hot plate and paw formalin models in mice. The motor effects were assessed with the rota-rod and open field assays. The volatile components obtained by headspace solid phase microextraction (HS-SPME) and hydrodistillation were determined using gas chromatography coupled with mass spectrometry (GC–MS) analysis. Results EO decreased first and second phases of formalin test; in the first stage, the better effect was obtained with the treatment of 316 mg/kg but in the second phase, time licking was attenuated at the doses of 31.6, 100 and 316 mg/kg. The effectiveness of EO (ED 50 =25.9 mg/kg) for attenuating neurogenic pain was corroborated using the hot plate test. The antinociceptive action of EO was blocked by naloxone suggesting that its mode of action involved an opioid mechanism. Furthermore, EO (316 mg/kg) did not affect animal motor and coordination functions when tested by the rota-rod and open field tests. The latter results indicated that the pharmacological effects exerted by EO during the hot plate and formalin test are truly antinociceptive. GC–MS analysis of EO revealed that (±)-camphor, γ-terpineol, 1,8-cineole and borneol were the major volatile compounds of the plant. Conclusion EO from A. ludoviciana showed significant antinociceptive effect, which appeared to be partially mediated by the opioid system. These findings could support the long-term use of A. ludoviciana for treating painful complaints in Mexican folk medicine.