Abstract
Background and Objective: Several species of Conyza bonariensis (C bonariensis) and related species are used traditionally in the managementof pain and inflammatory conditions. The current study was aimed to evaluatethe analgesic and anti-inflammatory activities of C bonariensis in animal models of pain and inflammation. Methodology: For the analgesic effect, acetic acid and formalin-induced models of nociception were employed while the anti-inflammatory effect was assessed in the carrageenan-induced rat paw edema test. The data were analyzed by student's t-test and one-way ANOVA followed by Tukey-Kramer multiple comparisons. Results: The intraperitoneal (i.p.) administration of the methanolic extract (50-100 mg kg(-1)), butanol, chloroform and hexane fractions (25-50 mg kg(-1) i.p) produced significant inhibition (p<0.01)ofthe acetic acid-induced writhing in mice and suppressed formalin-induced licking response of animals in the second phase of the test. C bonariensis (50-200 mg kg(-1) i.p.) produced marked anti-inflammatory effect in the carrageenan-induced rat paw edema assay comparable to indomethacin. Among various fractions of the plant, hexane and butonalic acid exhibited significant (p<0.05) anti-inflammatory effects. Conclusion: It is concluded that C bonariensis possesses analgesic and anti-inflammatory properties and that the bioactive bhytochemicals appeared to be concentrated in the hexane and butonalic fractions.