Impact of Croton argyrophyllus essential oil on behavioural models of nociception

Croton argyrophyllus Kunth (Euphorbiaceae) is a shrub abundant in the northeast region of Brazil where it possesses ethnobotanical use. To assess the antinociceptive action of C. argyrophyllus, studies were conducted in behavioural models of nociception, and some of the mechanisms given under this effect investigated. The essential oil (EO) of C. argyrophyllus leaves (10, 30 and 100 mg/kg) was used in mice via the oral route in both the chemicals (acetic acid, formalin, capsaicin and glutamate) and thermal nociception models. The EO produced inhibition of acetic acid‐induced visceral pain (10, 30 and 100 mg/kg, p.o.) and it produced a significant antinociception effect in the hot plate test (100 mg/kg). In the formalin test, the EO caused significant inhibition of both the early (100 mg/kg) and the late (30 and 100 mg/kg) phases of formalin‐induced licking. The EO (30 and 100 mg/kg) also caused significant inhibition of capsaicin‐ and glutamate‐induced pain. The EO (100 mg/kg) antinociception in the hot plate test was significantly attenuated by treatment with naloxone. In contrast, the EO (100 mg/kg) antinociception in the abdominal constriction test was not affected by treatment of mice with L‐arginine. The present results suggest that the EO from C. argyrophyllus produced antinociception in several models of pain in mechanisms that involved glutamatergic and opioid systems. Copyright © 2016 John Wiley & Sons, Ltd. The essential oil (EO) from Croton argyrophyllus Kunth leaves presents a pronounced antinociception in both the chemicals (acetic acid, formalin, capsaicin, and glutamate) and thermal (hot plate) models of nociception in mice. The antinociceptive effect of the EO involves an interaction with glutamatergic (through NMDA receptors) system and/or opioid receptors sensitive to naloxone. This biological action could be attributed, at least in part, to the high concentrations of bicyclogermacrene, (E)‐caryophyllene, and spathulenol.