Anti-inflammatory and analgesic activities of ethanolic extract of Chromolaena odorata leaves.

An ethanolic extract of Chromolaena odorata was investigated for its analgesic and anti-inflammatory activities in rats and mice. The analgesic activities was evaluated using the hot plate latency assay, formalin induced paw licking and acetic acid induced writhing tests while the anti inflammatory tests were carried out using the carrageenan induced paw oedema, cotton pellet granuloma and formalin induced arthritis models in rats. The result show that the extracts at the doses of 25-200 mg/kg significantly (P < 0.05) inhibited in a dose dependent manner the carrageenan induced paw oedema, the formalin induced arthritis and the cotton pellet induced granuloma models of inflammation. Similarly, the extracts (25-200 mg/kg) significantly, inhibited in a dose related manner the hot plate latency assay, the two phases of formalin induced paw licking and the acetic induced writhing (in mice) models of pain. These findings further support the previously reported analgesic and anti-inflammatory activities of an aqueous extract of the plant.