EVALUATION OF THE EFFECTS OF THE ROOT EXTRACT OF ASPARAGUS AFRICANUS LAM. ON GLUCOSE HANDLING IN NORMAL, GLUCOSE LOADED AND STREPTOZOCIN INDUCED DIABETIC RODENTS

Abstract

Background: Diabetes mellitus (DM) is a major metabolic disorder characterized by chronic hyperglycemia; with disturbances of carbohydrate, protein and fat metabolism resulting from defects in insulin secretion, insulin action or both. Despite the introduction of hypoglycemic agents, diabetes and related complications continue to be a major health problem in the 21st century. In addition, many oral hypoglycemic agents have got major side effects and cannot be used during pregnancy. Therefore, searching new antidiabetic agents of less toxic plant origin are continued to be an area of active research as WHO also recommends. Therefore the main objective of this study was to investigate the oral antidiabetic activity of crude extract of root of Asparagus africanus Lam in Rodent models. Materials and method: In all models, rodents were divided in to five groups each comprising of six animals. In hypoglycemic model healthy fasted mice and for antidiabetic studies Streptozocin 150 mg/kg induced diabetic mice, whereas for oral glucose tolerance test (OTT) rats were used. For group I distilled water was give as negative control, group II received 5mg/kg glibenclamide standard (GL5); groups III-V the extract of A. africanus 100 (AA100), 200 (AA200) and 400 (AA400) mg/kg/day, were given respectively. Blood samples were collected at different time points to determine blood glucose levels (BGL). Data were analyzed using one way ANOVA followed by Dunnet’s post hoc test and p<0.05 was considered as statistically significant. Results: In normal fasted mice, extract 200 mg/kg/day induced hypoglycemia starting from the 2nd h (p<0.05) but AA100 mg/kg/day and AA400 mg/kg/day failed to produce hypoglycemia at all time points. In Streptozocin induced diabetic mice AA200 mg/kg/day and AA400 mg/kg/day reduced BGL significantly since the 2nd h but at the 4th h lowered BGL very significantly (p< 0.001 in both cases). However, AA100 mg/kg/day revealed effect only at the 4th h (p<0.05) in diabetic mice. In OGTT, AA200 and GL5 (p<0.001) achieved effect since 60 min indicating the oral glucose load improving activity of the extract. It is worth nothing finding that AA200mg is competing with the standard in all models. Acute oral toxicity test revealed the extract was non toxic up to 5000 mg/kg. Phytochemical screening demonstrated presence of bioactive molecules flavonoids, alkaloids, phenolic and others which ameliorates diabetes and its complications. Conclusion: The results of this study indicate A. africanus has potential antidiabetic actions, particularly at the dose of 200 mg/kg in experimental rodents supporting the traditional claim.