Analgesic Activity of Methanol Leaf Extract of <i>Tamarindus Indica<i/> Plant in Mice and Rats

Abstract

Tamarindus indica has several folkloric uses in the treatment of various ailments. This study evaluated the analgesic activity of methanol leaf extract of Tamarindus indica (MLETI) in mice and Wistar rats. Acute toxicity studies were conducted using both the modified method of Lorke and OECD 425 guidelines. The analgesic activity was tested using acetic acid-induced writhing test, hot plate and formalin-induced hind-paw licking. Glycosides, flavonoids, saponins, alkaloids, reducing sugars, steroids and terpenoids were identified from the MLETI following phytochemical analysis. The LD₅₀ was above 5000 mg/kg in both species. Compared to controls, the MLETI (50, 100, and 200 mg/kg) produced significant (p<0.001) dose-dependent reductions (33.6%, 35.5% and 47.2%) in acetic acid-induced writhes in the treated mice. MLETI also produced significant (p<0.005) analgesic effect with the hot plate-induced pain and significantly (p<0.001) inhibited formalin-induced paw-licking response in test rats compared to controls. This was higher in the second phase compared to the early phase at all the tested doses. The methanol leaf extract of Tamarindus indica possesses analgesic activity. It also contained glycosides, flavonoids, saponins, alkaloids, reducing sugars, steroids and terpenoids, some/all of which may be responsible for the observed centrally and peripherally mediated analgesic activities.

Keyword: Analgesic, Fabaceae, mice, Tamarindus indica, Wistar rats