The central analgesic and anti-inflammatory activities of the methanolic extract of Carthamus oxycantha

Abstract

The plant extract and fractions of Carthamus oxycantha (Compositae) were assessed for analgesic and antiinflammatory activities. Acetic acid and formalin-induced nociception, hot plate and carrageenan-induced rat paw oedema tests were employed to evaluate the analgesic and anti-inflammatory potential of the plant extract. The intraperitoneal (i.p.) administration of the methanolic extract (25-30 mg/kg), hexane (10-50 mg/kg, i.p.) and ethylacetate (50 and 100 mg/kg i.p.) fractions produced significant inhibition (P<0.01) of the acetic acid-induced writhing in mice and suppressed formalin-induced licking response of animals in both phases of the test. In the hot plate assay the plant extract (100 mg/kg i.p.) increased pain threshold of mice. Pre-treatment of animals with naloxone (5 mg/kg i.p.) abolished the analgesic effect of the C. oxycantha in formalin and hot plate tests. C. oxycantha (50-200 mg/kg i.p.) produced marked anti-inflammatory effect in carrageenan-induced rat paw edema assay comparable to diclofenac. These findings suggest that C. oxycantha possesses central analgesic and peripheral anti-inflammatory properties, with analgesic effects associated with the opioid system.