Composição química e avaliação do potencial antinociceptivo do óleo essencial de Lippia bromelyana Moldenke (Verbenaceae) em camundongos

Abstract

Aromatic plants of the genus Lippia (Verbenaceae) are widely used in traditional medicine. A number of Lippia species can be found in the Caatinga biome in Northeastern Brazil, such as Lippia bromelyana Moldenke, endemic to the state of Bahia. This study investigated the chemical composition, acute toxicity, antinociceptive and anti-inflammatory effect of the leaf essential oil of L. bromelyana (EOLB) in mice.The chemical composition of EOLB, assessed by gas chromatography with flame ionization detection (GC/FID) and gas chromatography-mass spectrometry (GC/MS), detected limonene (29.90%) and piperitenone oxide (26.91%) as major compounds. Intraperitoneal administration of 300 mg/kg of EOLB caused no acute toxic effects or deaths in the mice. At doses of 75, 150 and 300 mg/kg caused no changes in their motor activity in the rotarod test, but promoted a significant antinociceptive effect on abdominal contortions in the acetic acid-induced constriction test, in both phases of the formalin test, glutamate or cinnamaldehyde-induced nociception tests and the Randall-Selitto test. In the hot plate test, EOLB (150 or 300 mg/kg) increased latency at 30, 60 and 120 min after administration; at a dose of 300 mg/kg, the action reversed by naloxone suggests participation of the opioid pathway. Moreover, EOLB (75, 150 or 300 mg/kg) significantly reduced the inflammatory effect of carrageenan in the paw edema test. Thus, these results suggest that EOLB promotes antinociceptive and anti-inflammatory activity by central and peripheral action.