Natriuretic and diuretic effects of Tropaeolum majus (Tropaeolaceae) in rats

Tropaeolum majus L. (Tropaeolaceae), popularly known as “chaguinha”, is well recognized in Brazilian traditional medicine as diuretic agent, although no scientific data have been published to support this effect.Aim of the studyTo evaluate the diuretic activity of the infusion and the hydroethanolic extract (HETM) of Tropaeolum majus, and possible mechanism of action.Material and methodsThe infusions (2,5 – 10%) and the HETM doses (150, 300 mg/kg) were orally administered to rats. Urinary excretion, the electrolytes levels, and urea and creatinine were measured in of saline-loaded rats.ResultsThe oral administration of 10% (corresponding to 500 mg/kg) of the infusion increased significantly the urinary Na+ excretion. Only the oral administration of 300 mg/kg of HETM increased significantly the urinary and Na+ excretion. Prolonged administration of the HETM (300 mg/kg) significantly increased diuresis and the urinary excretion of Na+, but others parameters were unaffected. To gain some evidence in possible involvement of prostaglandins system in diuretic action, the oral administration of HETM (300  mg/kg) in association indomethacin (5 mg/kg) reduced the urinary and sodium excretion when compared only HETM group.ConclusionThe results suggest that HETM could present compound(s) responsible for diuretic activities with no signs of toxicity, and the mechanism could involve prostaglandin system.