Evaluation of the Antioxidant and Analgesic Activities of Hydromethanolic Extract of Chromolaena odorata Leaf

Objective: The aim of the study was to evaluate the analgesic and antioxidant effects of hydromethanolic extract of Chromolaena odorata leaf in rodents.

Methods: The antioxidant activities were evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) Assay. Acetic acid induced writhing reflex and tail flick models were used in the evaluation of the analgesic activities. The rats were grouped into five (A-E) groups of six rats each. The group A and B received 10 ml/kg of water and 200 mg/kg of aspirin respectively. Group C-E received 100 mg/kg, 200 mg/kg and 400 mg/kg of the extract respectively.

Results: The extract caused a significant (p<0.05) decrease in pain sensation in both models. In acetic acid induced writhing, the extract (200 and 400 mg/kg) produced 13.13% and 27.27% reduction in number of writhing in treated rats respectively, when compared to the negative control. In tail flick model, the extract (200 and 400 mg/kg) caused 33.33% and 45.33% increase in pain reaction time (PRT) in the treated group respectively, when compared to the negative control group. In DPPH assay the extract produced a concentration dependent increase in antioxidant activity while in FRAP, there was no concentration dependent increase in antioxidant activity.

Conclusion: Hydromethanolic extract of Chromolaena odorata produced a potent analgesic and antioxidant in rodents.