Antilithiatic effects of crocin on ethylene glycol-induced lithiasis in rats

In this study, the antilithiatic potential of crocin, a pharmacologically active constituent of Crocus sativus L. (saffron), was evaluated against ethylene glycol (EG)-induced nephrolithiasis in rats. Negative control rats were provided with EG (1 %) in drinking water for 30 days. crocin (10, 20 and 40 mg/kg, i.p.) was administered simultaneously once daily for 30 days (prophylactic regimen) or 14 days after stone induction (therapeutic study). For biochemical analysis, 24-h urine was collected from all experimental animals at the beginning (day 0) and end of the experiment (day 30). The urine output was evaluated during the first 24 h (day 1). Ethylene glycol feeding resulted in decreased hyperoxaluria (P < 0.01) and total protein loss (P < 0.001), along with decreased excretion of citrate and magnesium (P < 0.01) compared with the intact animals. Treatment with prophylactic regimen of crocin (20 and 40 mg/kg) significantly reduced the elevated oxalate, and increased the citrate and magnesium levels of urine. The attenuation of protein loss was only seen with a high dose of crocin in a prophylactic study. Urine volume was not significantly altered after EG or crocin administration. The increased number of calcium deposits in the kidney tissue of lithiatic rats was decreased after prophylactic treatment with 20 and 40 mg/kg of crocin. The urinary ionic parameters and crystal count were not significantly altered after the therapeutic study. A marked increase in malondialdehyde (MDA, a lipid peroxidation product) level was observed in the EG-given group. Treatment with crocin (20 and 40 mg/kg) reduced the elevated levels of MDA. Results indicate that crocin can be effective in preventing urine calculi formation and recurrence of the disease. The mechanism underlying this effect is mediated possibly through balancing promoter and inhibitor factors and an antioxidant effect.