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

Volatile constituents and behavioral change induced by Cymbopogon winterianus leaf essential oil in rodents

Cymbopogon winterianus Jowitt (‘Java citronella’) is an important essential oil yielding aromatic grass cultivated in India and Brazil and its volatile essential oils extracted from its leaves are used in perfumery, cosmetics, pharmaceuticals and flavoring industries. However, there is no report on any psychopharmacological study of C. winterianus leaf essential oil (LEO) available to date. In this study, the pharmacological effects of the LEO were investigated in animal models and its phytochemical analyses. GC-MS analysis showed a mixture of monoterpenes, as citronellal (36.19%), geraniol (32.82%) and citronellol (11.37%). LEO exhibited an inhibitory effect on the locomotor activity of mice, an antinociceptive effect by increasing the reaction time in the writhing and capsaicin tests. All doses induced a significant increase in the sleeping time of animals not having modified however, the latency. The LEO did not alter the remaining time of the animals on the rota-rod apparatus. These results suggest a possible central effect.Key words: Cymbopogon winterianus, essential oil, CNS, behavioral effects, analgesic