Diuretic activity of Spilanthes acmella flowers in rats

Abstract

ln the Sri Lankan traditional medicine. Spilanthes acmella Murr. (Family: Compositae) flowers are claimed to possess powerful diuretic activity. However, as yet, the diuretic potential of these flowers is not investigated by scientifically controlled studies. The aim of rhis study was to evaluate the diuretic potential of Spilanthes acmella flowers in rats using a cold-water extract (CWE). Difl-erent concentrations of CWE (-500. 1 000, I 500 mgArg) or vehiclc or furoscmide ( 13 mg/kg) were orally administered (// : 6 per each treatrrent -uroLrp) to hydrated rats and their urine output was monitored at several intervals of time (l*-5h). The highest dose of CWE significantly (P < 0.0-5) and markedly increased the urine output. The onset of this diurctic actjon was extremeiy prompt (within I h) and lasted thror-rghoLlt the stuciied pedocl (up to -5 h). The peak efTect was evident between 1 and 2 h. Further, the intensity of diLrresis induced by the CWE in the first hi..ur rvas almost simiiar to that of furosemide. Spilanthes acmella CWE also caused marked increase in urinary Na+ and K+ levels and a reduction in the osmolarity of urine suggesting that it is mainly acting as a loop diuretic. lt may also inhibit ADH release and/or action. It is concluded that the Spilanthes acmella CWE has strong diuretic action as is claimed.