Anti-Inflammatory Activity of the Stem Bark Methanol Extract of Picralima nitida

Aims: To investigate the anti-inflammatory activity of Picralima nitida stem bark methanol extract (PNSBE). Study Design: The study was carried out using in vivo (carrageenan-induced paw oedema and egg albumin-induced paw oedema) and in vitro (Human red blood cell (HRBC) membrane stabilization assay) models in rat. Place and Duration of Study: Department of Veterinary Physiology and Pharmacology, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria from March to July, 2020. Methodology: The extract was used at the doses of 100, 200 and 400 mg/kg while diclofenac (20 mg/kg) was used as the standard reference drug for the in vivo study (carrageenan-induced paw oedema and egg albumin). For the in vitro study (red blood cell haemolysis), the extract was used at the concentrations of 25, 50, 100, 200 and 400 µg/ml while diclofenac 250 µg/ml was used. Results: In the carrageenan-induced paw oedema model, the extract at the doses used and the reference drug significantly (p < 0.05) reduced the paw edema in the rats at 1 hour in a dose dependent manner. Also, in the egg albumin model, the paw oedema of treated rats was significantly (P < 0.05) reduced by PNSBE dose dependently reducing the mean rat paw oedema from 0.99 ± 0.12 to 0.61 ± 0.06 at the first hour. There was also a concentration dependent inhibition of red blood cell haemolysis by the extract in the HRBC membrane stabilization assay. Conclusion: Picralma nitida demonstrated a significant anti-inflammatory activity in this study.