Effects of Aqueous Fraction of Ethanolic Extract of Balanites aegyptiaca Stem-bark on Glucose Metabolic Enzymes in Streptozotocin-induced Diabetic Rats

Abstract

Aims: The study examines effect of aqueous-fraction of ethanolic extract of Balanites aegyptiaca Stem-bark on enzymes of glucose metabolism in streptozotocin (STZ) diabetic rats in a bid to understand its antihyperglycemic mechanism of action. Methodology: Diabetes was induced in male rats by intra-peritoneal injection of 60 mg/kg body weight of STZ. Balanites aegyptiaca stem-bark was extracted using ethanol followed by solvent-solvent fractionation with ethyl acetate and water. The aqueous fraction obtained was subjected to acute toxicity on wistar rats using a gradient dosage, 1/10th of lethal dose was calculated and used for the study. It was orally administered at a dose of 400 mg/kg body wt to diabetic rats, metformin (200 mg/kg body wt) serve as reference drug and diabetic/normal controls received 10% dimethyl sulfurdioxide (DMSO) 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 bwt therefore, the LD50 value was considered to be more than 4000 mg/kg body wt. When the streptozotocin induced diabetic rats were treated with aqueous-fraction of the stem-bark ethanolic extract a significant (P≤0.05) regulation in glucose metabolic enzymes were noticed; glucokinase activity increased (3.04±0.004 U/min/mg protein) against diabetic control (2.22±0.016 U/min/mg protein) as well as glycogen synthase (0.13±0.001 U/min/mg protein) against diabetic control (0.09±0.003 U/min/mg protein). Glucose-6-phosphatase activity decreased (0.26±0.028 U/min/mg protein) against untreated diabetes (1.44±0.0.054 U/min/mg protein). Glycogen content increased to 13.77±0.32 mg/g liver compared to diabetic control (10.69±0.32 mg/g liver). A significant effect on fasting blood glucose was observed; treated diabetes (290.4±18.4 mg/dL) compared to diabetic control (336.0±11.9 mg/dL). Conclusion: These results indicated that Balanites aegyptiaca stem-bark contained compound(s) that regulates glucose metabolic enzymes to achieved its antihyperglycemic effect.