Hypoglycaemic activity of Retama raetam in rats.

The purpose of this study was to determine the underlying mechanism of the hypoglycaemic activity of an aqueous extract perfusion of Retama raetam (RR) in normal and streptozotocin-induced diabetic rats. The aqueous extract was administered intravenously and the blood glucose changes were determined within 4 h after starting the treatment. Plasma insulin concentrations and glycosuria were determined. The aqueous RR extract at a dose of 10 mg[sol ]kg[sol ]h produced a significant decrease in blood glucose levels in normal rats (p < 0.001) and an even more marked decrease in diabetic rats (p < 0.001). This hypoglycaemic effect might be due to an extra-pancreatic action of the aqueous extract of RR, since the basal plasma insulin concentrations were unchanged after RR treatment. A potent increase of glycosuria was observed both in normal and diabetic rats (p < 0.001). It is concluded that an aqueous extract perfusion of RR caused a potent inhibition of renal glucose reabsorption. This renal effect is at least one mechanism to explain the observed hypoglycaemic activity of this plant in normal and diabetic rats. Copyright 2005 John Wiley & Sons, Ltd.