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

Because many diabetic patients in the United Arab Emirates use medicin al plants as a supplement to treatment with insulin or oral hypoglycae mic agents, the effect on plasma glucose, insulin and glucagon concent rations 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, 2.0 and 4.0gkg (-1) did not significantly affect the concentration of glucose, insuli n or glucagon for up to 4h after administration of the extract. The sa me doses in diabetic rats reduced the glucose level 1h (2 and 4gkg(-1) ) and 2h (4gkg(-1)) after administration of the extract. This was acco mpanied by significant increases in insulin concentration 1, 2 and 4h after administration of the extract at doses of 2 and 4gkg(-1). Gliben clamide (2.5, 5.0 and 10.0mgkg(-1)) dose-dependently reduced glucose a nd glucagon levels, and increased that of insulin in normal and diabet ic rats. Simultaneous treatment of normal and diabetic rats with the p lant extract (0.5, 2.0 and 5.0gkg(-1)) and glibenclamide (5.0mgkg(-1)) significantly exacerbated the effects on glucose, insulin and glucago n induced by the extract or by glibenclamide when given separately. Wh en the plant extract was given at doses of 0.5, 2 and 4gkg(-1) 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 lev els of cholesterol or protein. These results imply that co-administrat ion of the extract with glibenclamide might adversely interfere with g lycaemic control in diabetic patients.