ABSTRACT
Aims:The study examines effect of aqueous-fraction of ethanolic extractof Balanites aegyptiacastem-bark on enzymes of glucose metabolism in streptozotocin (STZ)-induced diabetic rats in a bid to ascertain its anti-hyperglycemic and possible mechanism of action.Methodology:Diabetes was induced in male rats by intra-peritoneal injection of 60 mg/kg body weight of STZ. Dried powdered Balanitesaegyptiacastem-bark was defatted with hexane and extracted using ethanol followed by solvent-solvent fractionation with water and ethyl acetate. The aqueous fraction (ASF) obtained was subjected to acute toxicity on wistar rats using a gradient dosage, where 1/10thof lethal dose was calculated and used for the study. It was orally administered at a dose of 400 mg/kg body weight of diabetic rats, metformin (200 mg/kg body wt) serve as reference drug and diabetic/normal untreated rats received 10 % dimethyl sulfurdioxide for the 28 days treatment period. On day 29th, rats were sacrificed; blood and liver samples were collected. Liver tissues were homogenized, centrifuged and the supernatants were used for assay of glucose metabolic enzymes while serum was used for biochemical markers estimations.Results:Results obtained showed no death or lethal effect in the acute toxicity study up to a dose of 4000 mg/kg body wt. Therefore, the LD50value was considered to be more than 4000 mg/kg body wt.Streptozotocin-induced diabetic rats treated with ASF showed a significant (P<0.05) reversal effect in activities of the glucose metabolic enzymes assayed compare to untreated diabetic rats. Glucokinase activity was enhanced (2.98±2.23U/min/mg Protein) against untreated diabetic (2.22±0.02 U/min/mg Protein) as well as glycogen synthase (12.48±0.11x10-2U/min/mg Protein) against untreated diabetic (9.41±0.34x10-2U/min/mg Protein. Glucose-6-phosphatase activity was suppressed in the diabetic rats received ASF (0.26±0.03 U/min/mg Protein) compare to the untreated diabetic (1.44±0.05 U/min/mg Protein). Glycogen content of the treated diabetic ratswas elevated to 13.77±0.32 mg/g liver against the diabetic untreated rats (10.69±0.32 mg/g liver).A significant reduction in fasting blood glucose was recorded from the ASF treated diabetic rats (290.4±18.4mg/dL) compared to diabetic untreated rats (336.0±11.9mg/dL). Conclusion: The study suggested that Balanites aegyptiacastem-bark may contained compound(s) that has the capacity to reverse the activity of glucose metabolic enzymes to exert antihyperglycemic activity.