Toxicopathological evaluation of Picralima nitida seed aqueous extract in Wistar rats

Objective: Picralima nitida is a widely used medicinal plant in West Africa for treating malaria, diarrhea and inflammation. The objective of this study is to evaluate the toxicological effect of aqueous seed extract of the plant in Wistar rats. Methods: Twenty-four apparently healthy animals were randomized into 4 groups comprising 6 rats each and orally administered with aqueous extract of P. nitida seeds at doses of 100, 200 and 400 mg/kg body weight with distilled water as control for 14 days. Specific liver and kidney function indices were assayed alongside haematological and histopathological analyses to monitor toxicity according to standard methods. Results: Phytochemical screening revealed the presence of alkaloids, glycosides, saponins, steroids and tannins. The extract had no significant effect on all kidney function indices assayed but caused a significant reduction (P < 0.05) in the activities of liver enzymes accompanied by significant decrease in liver to body weight ratio, serum total protein and globulin concentrations. No significant alteration was observed in the serum levels of albumin and conjugated bilirubin whereas the extract brought about significant increase (P < 0.05) in serum total bilirubin concentration. Haematological analysis revealed no significant effect on erythrocyte indices in contrast to white blood cell count and its differentials which were significantly elevated (P < 0.05) following extract administration. Histopathological studies further showed no distortion of cell structures in the studied organs. Conclusion: The available evidences in this study suggest that aqueous extract of P. nitida seeds exhibits mild and selective toxicity with liver as the target organ. Therefore, the herb may not be completely 'safe' as an oral remedy; and long term administration should be avoided.