Antinociceptive properties and acute toxicity of ethanol extract of Bromelia laciniosa Mart. ex Schult. f. (Bromeliaceae)

Purpose: To investigate the antinociceptive activity and acute toxicity of the ethanol extract of Bromelia laciniosa leaf.Methods: A high performance liquid chromatography HPLC fingerprint of phenolic compounds was developed. The antinociceptive effect of ethanol extract (Bl-EtOH) in mice was carried out using chemical (writhing and formalin) and thermal (hot plate) models of nociception. The acute toxicity of the extract was performed in mice using doses of 2.0 g/kg intraperitoneally and 5.0 g/kg orally. Blood was removed for laboratory analysis of hematological and biochemical parameters.Results: Bl-EtOH (100, 200 and 400 mg/kg, i.p.) reduced the number of writhing (91.80, 93.44 and 78.68 %, respectively) and the number of paw licks during the first (60.86, 62.84 and 66.79 %) and second phase (91.93, 82.18 and 88.73 %) of the formalin test. Naloxone (1.5 mg/kg, i.p.) antagonized the antinociceptive action of Bl-EtOH (100 mg/kg), and this finding suggests involvement of opioid mechanism. The effect of Bl-EtOH on hot plate response provides a confirmation of its central effect.Conclusion: B. laciniosa leaf extract has antinociceptive properties. Peripheral, and at least in part, central mechanisms, may be involved in this antinociceptive effect. The ethanol leaf extract apparently presents no significant toxicity.Keywords: Bromelia laciniosa, Nociception, Pain, Writhing, Acute toxicit