BENEFICIAL EFFECTS OF ROSMARINUS OFFICINALIS AND THYMUS NUMIDICUS ON KEY ENZYMES OF CARBOHYDRATE METABOLISM IN ALLOXAN-INDUCED DIABETIC RATS

Abstract

The aim of this study is to evaluate the protective effects of the ethyl acetate fraction of Rosmarinus officinalis (RO-EA) and Thymus numidicus (TN-EA) plant extracts on carbohydrate metabolism enzymes during diabetes mellitus. To achieve this objective, two experiments were carried out.  The first of which was evaluating the hypoglycemic and the anti-hyperglycemic effects on normal rats overloaded with glucose (4 mg/kg b.w), with the use of two doses (150 and 300 mg/kg b.w), for each plant in the presence of negative control (vehicle 0.5 ml/100 g b.w), and positive control (5 mg of glibenclamide /kg b.w).  The second experiment aims at studying the dose-dependent effect of the two plants’ extracts on carbohydrate metabolism in Wistar rats rendered diabetic by intraperitoneal injection of Alloxan at (120 mg/kg b.w); 54 male rats of the Wistar strain were divided into 09 groups with 06 rats per group. 03 of the groups have normal rats receiving vehicle (0.5 ml/100 g bw), TN-EA (300 mg/kg b.w), RO-EA (300 mg/kg b.w), respectively. The 06 remaining groups were composed of diabetic rats receiving vehicle (0.5 ml/b.w), TN-EA (150 and 300 mg/kg b.w), RO-EA (150 and 300 mg/kg b.w) Glibenclamide (5 mg/kg b.w), respectively. The process lasted for 21 days. Then we proceeded to the assays.

The analysis of the results showed a dose-dependent reduction in glycemia for the anti-hyperglycemic and hypoglycaemic tests of the RO-EA with the dose of 150 and 300 mg/kg b.w, the latter demonstrated a significant increase in insulin and hemoglobin hexokinase enzyme activity, glucose-6-phosphate dehydrogenase and a concomitant effect modulating plasma glucose levels. In addition to decreased plasma HbA1c levels, glucose-6-phosphatase and fructose-1,6-bisphosphatase enzymatic activity in diabetic rats. The administration of this fraction prevented the loss of body weight and led to an improvement in the activity of glycogen synthase and glycogen phosphorylase. In conclusion, the RO-EA fraction at a dose of 300 mg/kg b w has an anti-hyperglycemic power in diabetic rats, these results were confirmed by histological examination of the liver.