Effect of Lepidium sativum L. on renal glucose reabsorption and urinary TGF-beta 1 levels in diabetic rats

The purpose of this study was to determine the mechanism underlying the hypoglycaemic activity of the aqueous extract perfusion of Lepidium sativum L. (LS) in normal and streptozotocin-induced diabetic rats. The aqueous LS extract was administered intravenously and the blood glucose levels were determined within 4 h of treatment. Plasma insulin concentrations and glycosuria were determined. The 24 h urinary transforming growth factor-beta 1 (ELISA) was evaluated in diabetic and control rats 15 days after oral treatment with the aqueous LS extract at a dose of 20 mg/kg. The study showed that LS at a dose of 10 mg/kg/h reduced blood glucose levels both in normal and diabetic rats (p < 0.001). At the same time as a potent increase of glycosuria was observed both in normal and diabetic rats (p < 0.001). In addition, oral administration of LS for 15 days normalized glycaemia (p < 0.001), enhanced glycosuria (p < 0.05 vs diabetic control) and decreased the amount of urinary TGF-beta 1 (p < 0.01) in diabetic rats. It is concluded that the aqueous LS extract caused a potent inhibition of renal glucose reabsorption which in turn reduced blood sugar. This renal effect is at least one mechanism explaining the observed hypoglycaemic activity of this plant in normal and diabetic rats. Copyright (c) 2007 John Wiley & Sons, Ltd.