The Effect of the Alcoholic Extract of Black Cumin (Nigella Sativa) on Stone Size in Patients with Oxalate Calcium Kidney Stones

Background: Nephrolithiasis (kidney stone) is a systemic disease associated with metabolic disorders. Regarding the beneficial properties of Nigella sativa, including diuretic and its inhibitory effects of calcium oxalate crystals deposition, this study aimed to investigate the effect of the alcoholic extract of Nigella sativa on kidney stone size in patients.Methods: This study was a clinical trial conducted from June 2020 to December 2021 in Qazvin, Iran. 50 patients with kidney stones were allocated to two groups using the randomized block sampling method. For 12 weeks, the intervention group received a capsule containing alcoholic extract Nigella sativa (100 mg) two times per day and the control group received their usual treatment. pH, urinary oxalate and citrate, the size of the stone (sonography) were measured before and after the intervention. Paired t-test and independent t-test were used to compare the quantitative mean of the data.Findings: Despite the decrease in stone size in the intervention group, no statistical significance in difference between both groups was observed. The amount of urinary oxalate in the intervention group was significantly reduced compared to the control group. There were no significant differences in terms of urine volume, pH, citrate levels between the two groups.Conclusion: Findings of this study showed that alcoholic extract of Nigella sativa can be effective to prevent the accumulation of calcium oxalate crystals by reducing urinary oxalate. Although a complete understanding of the mechanism is unknown.