EFFECT OF NATURAL PRODUCT EXTRACTS IN CALCIUM OXALATE MONOHYDRATE CRYSTALLIZATION

Abstract

Kidney stone formation is a major health problem all over the world. Calcium oxalate monohydrate (COM) kidney stones are the most common type ofkidney stone (renal calculi); about 70% to 80% of kidney stones are formed from COMcrystals. The mechanism underlying calcium oxalate stone formation is complex and not completely understood. Therefore, better understanding of calcium oxalate monohydrate crystallization is in urgent need to find out much efficient drug for inhibition kidney stone formation. This study was carried out using herbal extracts as crystallization inhibitors of kidney stone. Crystallization kinetics of calcium oxalate monohydrate (COM) was studied with and without an aqueous Ammi Visnaga(Khella) and Nigella Sativa(Habbet El-Barakah) extracts individually. To our knowledge, it is the first time to study the effect of an aqueous Nigella Sativa extract on COM crystallization as well as it is the first time to compare Nigella Sativa extract effect with the effect of an aqueous Khella extract on the COM crystallization. The induction period was determined under different supersaturation ratios at 37 oC using the conductivity method. The induction time decreased exponentially with increasing super saturation ratio whereas the induction time was increased with addition of an aqueous Egyptian khella and Nigella Sativa extracts individually compared to without additives. By using theory of classical homogenous nucleation, the calculated surface energy was increased from 7.97 mJ/m2 without additive to 9.15 mJ/m2 and 10.31 mJ/m2 with Khella and Nigella Sativa extracts, respectively. However, the nucleation rate at a supersaturation ratio of 3.26 corresponding to 3.27 and 5.44 with Khella and Nigella Sativa extracts, respectively was decreased from 3.9 x 1029 nuclei/cm3.s (without additive) to 2.4 x 1029 nuclei/cm3.s and 1.3 x 1029 nuclei/cm3.s with Khella and Nigella Sativa extracts, respectively. The results indicate that increasing surface energy leads to decreasing nucleation rate. The number of molecules required for the formation of stable nucleus was calculated with and without addition of extracts at different supersaturation ratios. COM crystals were investigated by X Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X Ray Spectroscopy (EDX). SEM photomicrographs show formation of small crystals, less aggregated with extracts inhibitor compared with the baseline. This study can help us to find out much efficient medicine from herbs extract for removal/inhibition kidney stone formation. Keywords: Calcium oxalate monohydrate; Crystallization; Crystal morphology; Induction time; Crystal growth inhibitor.