Assessment of toxicologic and radical scavenging potentials of methanol extract of ageratum conyzoides

Aims: Ageratum conyzoides is an annual herbaceous plant commonly used in African traditional medicine as a purgative, antipyretic and wound dressing agent. The objective of this study was to investigate the free radical scavenging and toxicologic potentials of methanol extract of A.conzoides leaves in wistar rats. Methods: The ground plant leaves were macerated to prepare a methanol extract and the ability of the extract to scavenge DPPH and reduce Fe3+ to Fe2+ was assayed following standard methods. The acute toxicity test was done using eighteen (18) male albino mice. The limit test dose of 5000 mg/kg body weight (b.w.) was administered to the albino mice and then observed individually 24 hrs post-dosing. Sub-chronic toxicity was evaluated after administering daily oral doses of 100, 200 and 400 mg/kg (b.w.), for 28 days using thirty two (32) rats. The effect of the extract on liver and kidney functions were assessed following standard methods. Results: The extract scavenged DPPH in a dose dependent manner with EC50 of 3.88 µg/ml compared to ascorbic acid EC50 of 2.37 µg/ml also reduced Fe3+ to Fe2+ in a concentration dependent form. The limit dose of 5000 mg/kg did not cause any mortality or signs of acute toxicity in the rats tested during the observation period. In the sub-chronic tests, the results did not show any treatment–related abnormalities in biochemical parameters. However, urea was significantly (p<0.05) lower in the group treated with 500 mg/kg of A. conyzoides extract. Conclusion: The results suggest that the methanol extract of A. conyzoides is relatively safe when administered orally in rats and possesses free radical scavenging properties.