Hypoglycemic Effect of Dietary Fibre in Diabetic Rats

The present study concern the use of Egyptian grape (Vitis vinifera) leaves dietary fibre in treatment of Streptozotocin (STZ) diabetic rats. The chemical analyses of dried and milled grape leaves dietary fibre revealed the presence of higher amounts of total non–starch polysaccharides NSP (491.2±6.4 g/kg), contains cellulose (96.4±3.2 g/kg), insoluble and soluble NSP (337.4±3.4 and 153.8±2.8 g/kg, respectively). Chemical analysis of total NSP (Soluble and insoluble NSP) revealed the presence of higher amount of uronic acid (112.3±3.2 g/kg) as well as different amounts of monosaccharides, mainly consisiting of glucose, galactose, mannose, arabinose and xylose. The hypoglycemic and hypolipidemic effects of grape leaves dietary fibre (Calculated as total NSP) in Streptozotocin (STZ) diabetic rats as well as liver function test were studied over 8 weeks period. The diabetic rats were devided into 4 groups and each was administered with one of four different doses of total NSP (50,100,150 or 200 mg/kg, respectively). Higher significant decreases in the levels of glucose (160.1±9.4 and 210.1±10.8 mg/dl, respectively) and cholesterol (110.8±9.4 and 137.2±9.8 mg/dl, respectively) were observed in two groups (rats group 2 and 4) administered with dose of 100 and 200 mg dietary fibre/kg, particularly at 8 weeks. Significant decreases in the levels of glucose and cholesterol (340.4±8.9, 310±9 and 150.4±7.1, 145.2±9.6 respectively) were observed in other rat groups (group 1 and 3) administered with doses of 50, 150 mg dietary fibres/kg. Higher significant decrease of triglycerides levels (180.8±9.2 mg/dl) was observed in plasma of rats administered with dose of 100 mg/kg (group 2), while the other doses (50,150 and 200 mg/kg) exhibited gradually significant decreases (254.9±9.6, 366.8±8.6 and 366.7±9.4 mg/dl, respectively). The greatest reduction of glucose, cholesterol and triglycerides levels were observed in rats administered with doses of 100 and 200 mg/kg dietary fiber (61, 38% and 54, 49% and 23, 9% respectively), while less reduction was observed in rat groups administered with doses of 50 and 150 mg/kg dietary fiber (30, 16, 9 and 16, 19 and 6% respectively). Study on hypoglycemic effect of dietary fibre at different doses indicated higher significant reduced the plasma glucose level of the diabetic rats by 16-61%. Dietary fibre doses also had lowering effect on the activities of ALP, ALT and AST in serum of diabetic rats. Results showed significant decrease in the activity of ALP and ALT in plasma of diabetic rats administered with doses of 100 and 200 mg/kg dietary fibre (13.8±0.5, 36.3±5.1 and 17.2±1.1, 39.1±4.5 U/dl, respectively). Insignificant differences were observed in other 2 groups of diabetic rats administered with doses of 50 and 150 mg dietary fibre/kg (group1and 4). A marked reduction in ALP and ALT values (29 and 33%, respectively) were observed in group 2 more than the other three groups (9.3, 13, 12, 15% and 11, 28 % respectively). Result also showed gradually significant decrease in AST activities in plasma of all experimental rat groups throughout 8 weeks. According to these results, it can be concluded that the dietary fibre of grape leaves having hypoglycemic and hypolipidemic effects in STZ diabetic rats.