Diuretic activity of Withania aristata: an endemic Canary Island species.

This study reports on the pharmacological evaluation of the diuretic activity of an infusion and a methanol extract of Withania aristata Ait. in laboratory rats. Water excretion rate, pH, density, conductivity, and content of Na(+), K(+) and Cl(-) were measured in the urine of rats subjected to hypersaline conditions. Both the infusion and the methanol extract showed a significant diuretic effect compared with non-treated controls, with notable increases in the rates of water and sodium excretion. There was also a potassium retention effect. The diuretic effect did not appear to be related to the potassium content in the material tested, but did have some relation to its content of active polar compounds. The results justify the use of Withania aristata as a diuretic agent in folk medicine of the Canary Islands.