Evaluation of the antiurolithiatic activity of the extract of Costus spiralis Roscoe in rats.

The antiurolithiatic activity of the water extract of Costus spiralis Roscoe was tested on formation of calculi on implants of calcium oxalate crystals or zinc disc in the urinary bladder of rats. The plant is a species from the family Zingiberaceae used in Brazilian folk medicine in urinary affections and for expelling urinary stones. Implantation of the foreign body in the urinary bladder of adult rats induced formation of urinary stones and hypertrophy of the smooth musculature. Oral treatment with the extract of Costus spiralis Roscoe (0.25 and 0.5 g/kg per day) after 4 weeks surgery reduced the growth of calculi, but it did not prevent hypertrophy of the organ smooth musculature. The contractile responses of isolated urinary bladder preparations to the muscarinic agonist bethanecol, in the presence and absence of the extract (0.3-3 mg/ml) or atropine (0.3-3 nM) did not differ among the experimental groups. The results indicate that the extract of Costus spiralis Roscoe is endowed with antiurolithiatic activity confirming thus folk information. The effect, however, was unrelated to increased diuresis or to a change of the muscarinic receptor affinity of the bladder smooth musculature to cholinergic ligands.