Antiurolithic effect of Bergenia ligulata rhizome: An explanation of the underlying mechanisms

Ethnopharmacological relevance: Bergenia ligulata is widely used plant in South Asia, mainly India and Pakistan, as a traditional medicine for treatment of urolithiasis. Aim of the study: To rationalize the Bergenia ligulata use in kidney stones and to explain the underlying mechanisms. Materials and methods: The crude aqueous-methanolic extract of Bergenia ligulata rhizome (BLR) was studied using in vitro and in vivo methods. Results: BLR inhibited calcium oxalate (CaC₂O₄) crystal aggregation as well as crystal formation in the metastable solutions and exhibited antioxidant effect against 1,1-diphenyl-2-picrylhydrazyl free radical and lipid peroxidation in the in vitro. BLR caused diuresis in rats accompanied by a saluretic effect. In an animal model of urolithiasis, developed in male Wistar rats by adding 0.75% ethylene glycol (EG) in drinking water, BLR (5-10 mg/kg) prevented CaC₂O₄ crystal deposition in the renal tubules. The lithogenic treatment caused polyuria, weight loss, impairment of renal function and oxidative stress, manifested as increased malondialdehyde and protein carbonyl contents, depleted reduced glutathione and decreased antioxidant enzyme activities of the kidneys, which were prevented by BLR. Unlike the untreated animals, EG intake did not cause excessive hyperoxaluria and hypocalciuria in BLR treated groups and there was a significant increase in the urinary Mg²⁺, instead of a slight decrease. Conclusions: These data indicate the antiurolithic activity in Bergenia ligulata mediated possibly through CaC₂O₄ crystal inhibition, diuretic, hypermagneseuric and antioxidant effects and this study rationalizes its medicinal use in urolithiasis.