Abstract
Pentavalent vanadium (metavanadate salt) toxicity is a challenging environmental hazard that affects living organisms. Studies have shown that plants play important roles in protecting against heavy metal toxicity. This study was designed to evaluate the protective activity of ethanolic extracts of Grewia carpinifolia leaves following vanadium toxicity.
Twenty five male Swiss mice were randomly divided into five groups (A–E) of five rats each. Group A rats served as control and were given distilled water, Group B was administered with sodium metavanadate and a known antioxidant agent; α-tocopherol, Groups C and D were administered with sodium metavanadate and ethanolic extract of Grewia carpinifolia leaves orally at 100 and 200 mg/kg body weight respectively while Group E was administered with only sodium metavanadate.
After a daily single oral dosing for seven days, changes in haematology and serum biochemistry parameters were analysed. Sodium metavanadate caused a significant decrease (p≤0.05) in haematocrit levels, haemoglobin (Hb) concentration, white blood cell count, neutrophil count and serum cholesterol level. A significant (p≤0.05) lymphocytosis was also observed in the group administered with sodium metavanadate alone. G. carpinifolia extract given concomitantly with sodium metavanadate was able to restore PCV, Hb concentrations and serum total protein to levels comparable with the control and standard groups. Grewia carpinifolia also significantly reduced the elevated serum levels of AST and ALT after vanadium induced hepatotoxicity. Our findings suggest that G. carpinifolia extract protected against the toxicity induced by vanadium; the plant extract at 200 mg/kg however appear to offer a better protection.

Key words: vanadium, Grewia carpinifolia, haematology, serum biochemistry, Swiss mice