Phytotherapy and renal stones: the role of antioxidants. A pilot study in Wistar rats.

Since ancient times, various herbal preparations have been used in renal lithiasis therapy, but conclusive scientific data on their therapeutic effects and efficacy are not available. To address this issue, the present study evaluated the antilithiasic activity of a traditional Mallorcan herbal preparation, and compared its effects with those of the antioxidant flavonoids, catechin and epicatechin. Thirty-six male Wistar rats were assigned randomly to four groups (n = 9): a control group, a catechin (CAT) treatment group, an epicatechin (EPI) treatment group, and a group treated with a folk herbal extract (FHE). After 16 days of treatment, calcium oxalate lithiasis was induced in the rats using ethylene glycol. After 8 days (treatment + ethylene glycol), 24-h rat urine was collected, the animals were sacrificed and their kidneys were removed for histological and chemical analysis. The calcium concentration in kidney tissue was significantly lower in the CAT-treated (2.4 +/- 0.3 mg/g), EPI-treated (1.8 +/- 0.3 mg/g) and FHE-treated (2.1 +/- 0.3 mg/g) groups, than in the control group (5.4 +/- 1.4 mg/g). Examination of paraffin-embedded kidney sections showed that control group rats had the greatest amount of calcification. There were no significant differences between control and treated groups with respect to urinary calcium, magnesium, oxalate and citrate concentrations. These results demonstrate the ability of herbal preparations and antioxidants to prevent the development of papillary and intratubular calcification in the kidney.