Acute and Subchronic Toxicity Studies of Combretum collinum Methanol Root Extract in Albino Rats

Combretum collinum root extract has been recognized long ago as traditional medicinal plant in curing several diseases among the indigenous people of Alela-land (Zuru), Kebbi State, Nigeria. This research work was carried out to evaluate the toxicological effects of Combretum collinum methanol root extract (CCME) in albino rats. Acute toxicity was performed by a fixed single oral administration at a dose of 10, 100, 1000 mg/Kg and 1600, 2900, 5000 mg/Kg. Subchronic toxicity studies of CCME was conducted at doses of 32, 63, 126 and 253 mg/Kg for 28 days. The result showed that acute administration of CCME resulted at mortality and general behavioral changes at 1000 to 5000 mg/Kg. Therefore, the estimated lethal dose (LD50) of CCME was 316.23 mg/Kg. Subchronic oral administration of CCME revealed a significant (P<0.01) decrease in body weight in rats receiving 63 to 253 mg/Kg throughout the study period compared with the control group. The results also showed a significant (P<0.01) increase in serum ALT, AST, creatinine, potassium and bicarbonate in rats administered with 126 and 253 mg/Kg of the extract. Haematological analysis of the same extract revealed a significant (P<0.01) increase in WBC, HCT, MCV, MCH, MCHC, PLT, LYM and NEUT in rats receiving 126 and 253 mg/Kg only. Histopathological examination of liver revealed severe periportal inflammation, hypertrophy, areas of hydropic changes, cancerous tumor, areas of infiltration and necrosis of the hepatic cells while the kidney showed a mild mesengial hyperplasia, compressed blood vessels, glomerular degeneration, tubular degeneration and tubular widened lumen in rats treated with 63 to 253 mg/Kg. Therefore, caution should be applied as C. collinum root extract has a low mean lethal dose and would be toxic at higher concentrations.