Evaluation of the diuretic effect of the aqueous extract of Costus pictus D. Don in rat

The aerial part of Costus pictus D. Don is used in Mexican Folk Medicine to treat renal diseases. The aim of this study is to measure the diuretic effect of an aqueous extract of this plant at doses of 100 and 200 mg/kg body weight (b. wt.) and to compare it with the one induced by furosemide at 4 mg/kg. Agents were administered orally to adult rats and the effects on sodium, potassium and water balance were assessed. Aqueous extracts at both doses and furosemide produced significant increments in free water and osmolal clearances and in urinary excretion of sodium and potassium in rats with respect to the control group. Fractional excretion of sodium and potassium were augmented in the treated groups only at a 200 mg/kg dose and the furosemide treated-group. At the same time, the creatinine clearance remained unchanged. The lethal dose 50% of Costus pictus D. Don is higher than 40g/kg b wt. These results suggest that the aqueous extract of Costus pictus D. Don at 200 mg/kg (b.wt.) induces a natriuretic response similar to that of furosemide.