Phytochemical, anti-inflammatory and analgesic properties of stembark extract and fractions of Lonchocarpus sericeus Poir. (Papilionaceae) in albino mice

OBJECTIVE: Lonchocarpus sericeus stembark decoction has been extensively employed in folkloric medicine in many parts of Nigeria as a remedy for pain as well as inflammation. The plant was studied for its anti-inflammatory as well as analgesic potency using standard biological models. MATERIALS AND METHODS: The stembark of L. sericeus was evaluated for anti-inflammatory properties using egg albumin and xylene-induced oedema models. The pain-relieving property was evaluated using acetic acid-induced writhing and thermally-induced pain models. Median lethal dose determination (intraperitoneal LD(50)), quantification of some phytochemicals as well as phytochemical screening were also performed. RESULTS: The LD(50) of stembark extract of L. sericeus was found to be 3,100 mg/kg (i. p). The crude extract and fractions (310-930 mg/kg) effectively reduced oedema caused by egg albumin and xylene and exhibited high analgesic properties in inhibiting pain induced by acetic acid and heat. These reductions were dose-dependent and statistically significant (p<0.05-0.001) when compared to distilled water and similar to prototype drugs employed. Quantitative determinations of some bio-active constituents of the plant showed a higher flavonoid content (0.52±0.02 mg/100 g) compared to alkaloids (0.36±0.02 mg/100 g) and flavonoids (0.49±0.03 mg/100 g). Phytochemical screening of the stembark showed the presence of alkaloids, cardiac glycosides, flavonoids terpenes, tannins and saponins. CONCLUSION: These results imply that the stembark extract of L. sericeus possesses anti-inflammatory and analgesic potency and these data validate its wide use in folkloric medicine for inflammation and pain management.