Antiurolithiatic activity of saponin rich fraction from the fruits of Solanum xanthocarpum Schrad. & Wendl. (Solanaceae) against ethylene glycol induced urolithiasis in rats.

BACKGROUND

A well-known traditional herb Solanum xanthocarpum is widely used in India for the management of different ailments including urolithiasis. This study was designed to rationalize the use of Solanum xanthocarpum in kidney stone and to investigate its mechanism of action.

METHODS

The saponin rich fraction prepared from fruits of Solanum xanthocarpum (SXS) was evaluated for antiurolithiatic activity by in vitro and in vivo studies. In ethylene glycol (EG, 0.75% in drinking water for 28 days) induced urolithiasis model, two different experimental doses (20 mg/kg and 40 mg/kg, p.o., for 28 days) of saponin rich fraction were selected by dose fixation study. After 28 days, various biochemical parameters were measured in urine, serum and kidney homogenate. Kidneys were also subjected to histopathological analysis.

RESULTS

In vitro calcium oxalate crystal (CaOx) nucleation as well as aggregation was inhibited in artificial urine solution by SXS. The lithogenic treatment caused polyuria, damage renal function and oxidative stress, manifested as increased malondialdehyde, depleted reduced glutathione and decreased antioxidant enzyme catalase activities of the kidneys, which were prevented by simultaneous administration with SXS. Lithogenic treatment also caused crystalluria, hyperoxaluria, hypercalciuria, hypocitrauria, and hypomagnesaemia. Deposition of CaOx in renal tissue and cellular injury were seen in histopathology. Co-administration of SXS had potential to prevent these pathological changes due to lithogenic treatment. Moreover, SXS raised level of glycosaminoglycan, a stone inhibitor macromolecule found in urine which decreased.

CONCLUSIONS

The antiurolithiatic activity in Solanum xanthocarpum is mediated possibly through the inhibition of CaOx crystal formation and its effect on the urinary concentration of stone-forming constituents and nephrolithiasis inducing factors and this study rationalizes its medicinal use in urolithiasis.