The Effect on Plasma Glucose, Insulin and Glucagon Levels of Treatment of Diabetic Rats with the Medicinal Plant Rhazya stricta and with Glibenclamide, Alone and in Combination

Abstract

Abstract Because many diabetic patients in the United Arab Emirates use medicinal plants as a supplement to treatment with insulin or oral hypoglycaemic agents, the effect on plasma glucose, insulin and glucagon concentrations of simultaneous treatment of streptozotocin-diabetic rats with Rhazya stricta extract and glibenclamide has been examined. Treatment of control rats with the extract at oral doses of 0.5, 20 and 4.0 g kg− did not significantly affect the concentration of glucose, insulin or glucagon for up to 4 h after administration of the extract. The same doses in diabetic rats reduced the glucose level 1 h (2 and 4 gkg−) and 2h (4 gkg−) after administration of the extract. This was accompanied by significant increases in insulin concentration 1, 2 and 4 h after administration of the extract at doses of 2 and 4 gkg−. Glibenclamide (2.5, 5.0 and 10.0 mgkg−) dose-dependently reduced glucose and glucagon levels, and increased that of insulin in normal and diabetic rats. Simultaneous treatment of normal and diabetic rats with the plant extract (0.5, 20 and 5.0 gkg−) and glibenclamide (5.0 mg kg−) significantly exacerbated the effects on glucose, insulin and glucagon induced by the extract or by glibenclamide when given separately. When the plant extract was given at doses of 0.5, 2 and 4 g kg− per day for 6 consecutive days the glucose level was reduced by approximately 6, 8 and 30%, respectively. No significant effect was seen on the levels of cholesterol or protein. These results imply that co-administration of the extract with glibenclamide might adversely interfere with glycaemic control in diabetic patients.