Inhibition of Urolithogenic Calcium Phosphate Mineralization by Some Natural Acids in Aqueous and Urinary Milieu

Objective: Calcium phosphate forms one of the important constituents of urinary stones. Present objective is to Study the inhibition of mineralization of urolithogenic calcium phosphate by some natural acids. This study would lead to trace the role of such acids in prevention / prophylaxis of phosphate urolithiasis. Methods: Inhibition of mineralization of urolithogenic calcium phosphate by some natural acids has been studied at a pH of 6.5 in aqueous and urinary milieu in an experimental model. Various natural acids studied were succinic, malic, citric, gluconic, aspartic or glutamic acid. Infrared spectra of the mineralized as well as sequestered (inhibited) phosphate, in the range of 4000-650 cm-1, has been recorded and studied. Results: Results revealed a moderate to good inhibition (12-75%) of phosphate by the natural acid inhibitors in aqueous medium. In urinary medium also moderate to good inhibition (16-94%) was observed. Infrared spectra suggested the precipitated phosphate to be calcium hydroxyapatite. Infrared spectra of the sequestered (inhibited) phosphate suggest it to be in a coordinated/complexed state. Conclusion: Natural acids inhibit calcium phosphate mineralization by soluble complexation. Cycling of these acids through the urinary tract would be helpful in the prevention/ prophylaxis of phosphate urolithiasis.

Author(s): TVRK Rao and Gunja Kumari

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