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Introduction: Nephrolithiasis is afflicting mankind thoughout the world. So far, five types of stones have been investigated. Of all types of renal stone, calcium oxalate (75%) and calcium phosphate (4%) are most common kidney stones. As found by chemical analysis kidney stones comprise an organic phase which constitutes biomolecules like protein, lipids etc. Based on previous reports, few inhibitors of crystallization have been isolated from this organic matrix. Thus, our aim was to isolate and then compare the inhibitory activity of biomolecules by in vitro calcium oxalate and calcium phosphate assay. Methods: Calcium oxalate stones were collected from PGIMER, Chandigarh after confirmation by FTIR analysis. The stones were powdered and protein extraction was done; 10 mL of 0.05 mol/L EGTA (pH 8.8) with 1mM PMSF was added per gram of powder and the suspension stirred for 4 days at 4 oC. The suspension was centrifuged for 30 min at 6000 g at 4 °C and the supernatant filtered. Lipids were extracted after demineralization of stone powder with EGTA. Results: Proteins showed higher inhibitory activity than lipids for calcium oxalate and calcium phosphate mineralization. Further, proteins were purified by ion exchange & molecular sieve chromatography. Anionic proteins which were eluted out showed higher activity than the cationic proteins. Conclusions: Not only anionic proteins but lipids are also involved in the inhibition of calcium oxalate and calcium phosphate mineralization. [ABSTRACT FROM AUTHOR]

In the Indian traditional system of medicine, Bergenia ligulata (Wall.) Engl. has been used for treatment of urolithiasis. Its efficacious nature has led to its incorporation in various commercial herbal formulations such as Cystone and Neeri which are prescribed for kidney related ailments. To assess whether ethanolic extract of B. ligulata can mitigate the cascade of inflammatory responses that cause oxidative stress and ultimately cell death in renal epithelial cells exposed to hyperoxaluric conditions. Bioactivity guided fractionation using solvents of varying polarities was employed to evaluate the potential of the extracts of B. ligulata to inhibit the crystallization process. Modulation of crystal morphology was visualized through Scanning electron microscopy (SEM) analysis. Cell death was assessed using flow cytometry based assays. Alteration in the inflammatory mediators was evaluated using real time PCR and immunocytochemistry. Phytochemical characterization of the ethanolic extract was carried out using FTIR, LC-MS and GC-MS. Bioactivity guided fractionation for the assessment of antilithiatic activity revealed dose dependent inhibition of nucleation and aggregation process of calcium oxalate crystals in the presence of various extracts, however ethanolic extract showed maximum inhibition and was chosen for further experiments. Studies on renal epithelial NRK-52E cells showed, cytoprotective efficacy of B. ligulata extract against oxalate injury. SEM anaysis further revealed the potential of the extract to modulate the crystal structure and adhesion to renal cell surface. Exposure of the renal cells to the extract led to conversion of the calcium oxalate monohydrate (COM) crystals to the less injurious calcium oxalate dihydrate (COD) form. Expression analysis for oxidative stress and inflammatory biomarkers in NRK-52E cells revealed up-regulation of Mitogen activated protein kinase (MAPK), Osteopontin (OPN) and Nuclear factor- ĸB (NF-ĸB), in response to calcium oxalate insult; which was drastically reduced in the presence of B. ligulata extract. Flow cytometric evaluation pointed to caspase 3 mediated apoptotic cell death in oxalate injured cells, which was attenuated by B. ligulata extract. Considering the complex multifactorial etiology of urolithiasis, ethanolic extract from B. ligulata can be a promising option for the management of kidney stones, as it has the potential to limit inflammation and the subsequent cell death. [Display omitted] [ABSTRACT FROM AUTHOR]