Prevention of nephrolithiasis by an extract of Ammi visnaga L. in stone forming rats

Hyperoxaluria is a major risk factor for renal stones [1]. Although effective treatments have been developed to remove kidney stones with minimum renal damage, the treatment of chronic stone occurrence remains frustrating [2]. The aim of this study was to evaluate whether oral administration of an aqueous extract prepared from the seeds of Ammi visnaga L. (Khella; Apiaceae) could prevent urolithiasis in stone-forming rats. Hyperoxaluria was induced in male Sprague-Dawley rats by giving 0.75% ethylene glycol (EG) and 1% NH₄Cl via the drinking water. The Khella extract (KE; 125, 250 or 500mg/kg) was orally administered for 14 days. Rats were sacrificed after 2 weeks and kidneys were harvested for the histopathological assay of crystal formation. 24h urine samples were collected before the animals were sacrificed. The histopathology examination of the kidneys revealed that KE significantly reduced the incidence of calcium oxalate deposition (Crystal deposition scale, Control (Untreated): 0±0, EG: 3.13±1.23, KE 125mg/kg: 1.63±1.19, KE 250mg/kg: 1.86±0.83, and KE 500mg/kg: 1.25±0.71). In addition, KE significantly increased urinary excretion of citrate (Control: 1.38±0.27mg/day, EG: 1.10±0.21mg/day, KE 125mg/kg: 4.0±0.67mg/day, KE 250mg/kg: 4.02±0.34mg/day, and KE 500mg/kg: 5.85±2.45mg/day) along with a decrease of oxalate excretion (Control: 0.45±0.05mg/day, EG: 1.01±0.34mg/day, KE 125mg/kg: 0.80±0.34mg/day, KE 250mg/kg: 0.58±0.22mg/day, and KE 500mg/kg: 0.57±0.15mg/day). In addition, KE increased the urine pH (Control: 6.03±0.11, EG: 5.64±0.1, KE 125mg/kg: 5.84±0.17, KE 250mg/kg: 5.91±0.18, and KE 500mg/kg: 6.05±0.15) in a dose dependent manner. In summary, a reasonably good correlation was obtained between the incidence of crystal deposition and the increase in urine pH. Our data suggest that KE may be used as a potential therapeutic strategy in the prevention of kidney stones caused by hyperoxaluria.

References: 1. Coe, F.L. et al. (2005)J. Clin. Invest. 115:2598–2608, 2. Begun, F.P. et al. (1991)J. Urol. 145:635–639.