Toxicity Studies of the Ethanolic Stem- Bark Extract of Milicia excelsa (Welw.) C. C. Berg in Wistar Rats

Thisstudy was designed to investigate the toxicity ofethanolic stem bark extract of M ilicia excelsa in wistar rats. The ethanolic extract was screened for secondary metabolites to determine its phytochemical constituents. The acute toxicity of the extract was determined in mice with a view to estimating its median lethal dose (LD 50 ). For sub-chronic toxicity study, twenty wistar rats with average weight of 184.50 ± 3.21 g were randomly assigned into four groups (I-IV) of five rats each. Animals in groups II-IV were orally administered with ethanolic extract at the doses of 250, 500 and 750 mg/kg body weight respectively once daily for 28 days, while those in the control group (group I) received 2 ml of 5% dimethyl sulphoxide (DMSO/water 5:95 v/v) daily. The results of this study showed that flavonoids, tannins, saponins, cardiac glycosides and terpenoids are the major secondary metabolites present in the extract. The LD 50 was found to be greater than 5 g/kg body weight. The results of biochemical analyses showed that the concentrations of plasma protein, albumin, bilirubin, creatinine and uric acid in the extract treated rats (groups II- IV) were not significantly different (p > 0.05) from the control (group I). Similarly, the activities of hepatic marker enzymes in the plasma showed that AST, ALP and GGT activities in all the treated groups were not significantly different from control group. However, the ALT activity of the extract treated groups was lower than its activity in the control group and the difference was statistically significant (p 0.05) from control group. The results of this study suggest that prolonged use of ethanolic stem bark extract of Milicia excelsa might not have adverse effects on the liver and kidney at the tested doses in this study.