Hypoglycaemic effect of Rubus fructicosis L. and Globularia alypum L. in normal and streptozotocin-induced diabetic rats.

The present study investigates the effect of oral administration of the aqueous extract of Rubus fructicosis L. (RF) and Globularia alypum L. (GA) leaves on blood glucose levels in normal and streptozotocin (STZ) diabetic rats. In normal rats, single and repeated oral administration of RF lowered significantly the blood glucose levels, while, GA treatment did not change blood glucose levels. In STZ rats, single and repeated oral administration of both RF and GA produced significant decrease of blood glucose levels. RF and GA treatments did not affect insulin secretion both in normal and STZ rats, indicating that mechanism(s) by which these plants decrease blood glucose levels is extra-pancreatic at least, for the doses used. In addition, the acute toxicity study revealed that the aqueous extracts may be considered relatively safe since that the LD(50) value was over 8.1 and 14.5 g/kg for RF and GA respectively. These findings indicate that RF and GA represent an effective blood glucose lowering and a potential source for discovery of new orally active component(s) for future therapy.