Inhibition of calcium oxalate crystallisation in vitro by an extract of Bergenia ciliata

OBJECTIVE To evaluate the effectiveness of an extract obtained from the rhizomes of Bergenia ciliata (Saxifragaceae) on the inhibition of calcium oxalate (CaOx) crystallisation in vitro. MATERIALS AND METHODS A hydro-alcoholic extract (30:70, v/v) of rhizomes of B. ciliata was prepared at different concentrations (1-10 mg/mL). The crystallisation of CaOx monohydrate (COM) was induced in a synthetic urine system. The nucleation and aggregation of COM crystals were measured using spectrophotometric methods. The rates of nucleation and aggregation were evaluated by comparing the slope of the turbidity of a control system with that of one exposed to the extract. The results were compared with a parallel study conducted with a marketed poly-herbal combination, Cystone, under identical concentrations. Crystals generated in the urine were also analysed by light microscopy. Statistical differences and percentage inhibitions were calculated and assessed. RESULTS The extract of B. ciliata was significantly more effective in inhibiting the nucleation and aggregation of COM crystals in a dose-dependent manner than was Cystone. Moreover, the extract induced more CaOx dihydrate crystals, with a significant reduction in the number and size of COM crystals. CONCLUSION An extract of the traditional herb B. ciliata has an excellent inhibitory activity on crystalluria and therefore might be beneficial in dissolving urinary stones. However, further study in animal models of urolithiasis is needed to evaluate its potential anti-urolithiatic activity.