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

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 LD50), quantification of some phytochemicals as well as phytochemical screening were also performed. Results: The LD50 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.