Abstract

This study was carried out to evaluate the antinociceptive effects of ethanolic extract fromNeoglaziovia variegata (Nv-EtOH) in mice using models of nociception. The evaluation of antinociceptive activity was carried out by the acetic acid-induced writhing, formalin and hot plate tests. HPLC was used to determine the fingerprint chromatogram of the Nv-EtOH. In the acetic acid-induced writhing test, the Nv-EtOH (100, 200 and 400 mg/kg, i.p.) reduced the number of writhing by 89.50, 71.34 and 87.42%, respectively. Additionally, the extract decreased by 46.67, 44.23 and 41.81%, respectively, the paw licking time in the first phase of the formalin test, as well as 70.14, 69.43 and 90.28%, respectively, in the second phase of this test. In the hot plate test, Nv-EtOH increased the reaction time when compared to control group. The effects of Nv-EtOH and morphine in the formalin and hot plate tests were antagonized by naloxone. The presence of phenolic compounds in the extract was confirmed using HPLC. Results based from formalin and hot plate tests indicated that the extract has compounds that interact with the opioid system. The effect of Nv-EtOH on hot plate response provides a confirmation of its central effect. Pharmacological and chemical studies are continuing in order to characterize the mechanism responsible for this effect.

Key words: Antinociceptive activity, phenolic compounds, Neoglaziovia variegata, Bromeliaceae.