A preliminary investigation on the effects of Polpala (Aerva lanata) on the structure and function of urinary tract of rats

Polpala (Aerva lanata) is a medicinal plant that is extensively used for the treatment of renal disease in Ayurvedic medicine. This preliminary investigation was carried out to evaluate the diuretic effect of the crude aqueous plant extract and high and low molecular mass fractions of this herb, using the hydrated rat assay technique. Possible toxicological effects on renal structure and function, mediated by long term administration of aqueous plant extract was also studied using two concentrations of both fresh and dried plant material, made according to Ayurvedic system of medicine in Sri Lanka. Urine output, osmolality and electrolyte excretion were measured to evaluate diuretic activity. Creatinine clearance and histopathological studies were done to evaluate toxicological effects on renal structure and function. Crude aqueous plant extract showed a diuretic activity with marked increase in urine output, urine osmolality and urinary potassium excretion. Low molecular mass fraction of dried plant material showed a significant diuretic effect while the high molecular fraction did not have the same effect. Investigations also showed that long term administration of the aqueous extract of this plant had no toxicological effects on renal structure and function of rats. Key words: polpala; Aerva lantana; diuretic activity; toxicological effects DOI = 10.4038/cjms.v48i2.120 The Ceylon Journal of Medical Science 2005; 48: 33-4