Analgesic activity of the aqueous leaf extract of Byrsocarpus coccineus

Abstract

Byrsocarpus coccineus (Schum. and Thonn.) is used as an herbal remedy for earache, muscular and rheumatic pains in West Africa. To validate the claim of the users, the analgesic effect of the aqueous leaf extract of the plant was studied in mice and rats using acetic acid-induced writhing, formalin, tail immersion, and cold-water tail flick pain tests. The extract (50 - 400mg/kg; p.o) showed a dose dependent and significant (p<0.05) inhibition of pain in the acetic acid-induced writhing, tail immersion, tail flick and the formalin (second phase) tests. The extract (400mg/kg) gave a significantly (p<0.05) higher inhibition than acetylsalicylic acid, ASA, (100mg/kg; p.o) in the acetic acid-induced writhing test. Its effect on the second phase of the formalin test was comparable to that of ASA. The elevation of pain threshold at 60 minutes post-treatment produced by 400mg/kg of the extract in the tail immersion and tail flick tests were slightly lower than that of morphine (2mg/kg; s.c). The results suggest that the aqueous leaf extract of Byrsocarpus coccineus possesses effective analgesic activity mediated via peripheral and central mechanisms.

Keywords: Byrsocarpus coccineus, analgesic, herbal remedy

Nigerian Journal of Health and Biomedical Sciences Vol. 5(1) 2006: 43-47