Analgesic activities of ethanolic extract of the root of Carpolobia lutea

The analgesic activities of the aqueous extract of Carpolobia lutea was evaluated in mice and rats using the mouse writhing, tail flick and formalin induced pain tests. Analgesic studies were performed using three models; mouse writhing assay, formalin test and tail flick assay. The extract (1500 to 2500 mg/kg) and acetylsalicylic acid (100 mg/kg) produced a significant (P<0.05) inhibition of the second phase in the formalin pain model, while the antinoceptive effect was not produced in the first phase. The extract also showed a dose dependent inhibition of acetic acid induced abdominal writhings. The tail flick latency was not enhanced by the extract. Oral administration of the extract up to 2500 mg/kg did not produce any toxic effects in the acute toxicity studies in mice. The LD50 of the extract when administered orally was 3338.83 mg/kg. The data obtained shows that C. lutea posseses analgesic activity that is peripherally mediated.