Comparative spectroscopic analysis of nordihydroguaiaretic acid and related natural products to inhibition of calcium oxalate calculi

Abstract

The prevalence of urolithiasis is still increasing worldwide. The goal of this study is to achieve a better understanding, from a comparative spectroscopic perspective, of the differences provided by chemical and natural products to the inhibitory processes of calculi formation. The research presented here places primary emphasis on the assessment of nordihydroguaiaretic acid (NDGA), the main chemical extract of the plant Larrea Tridentata, as a preventative to calcium oxalate crystal formation. It is also a logical continuation of our previous efforts using a traditional medicine approach to study such prevention. Complementary Raman and Fourier transformed infrared (FTIR) absorption analysis were used to provide a complete overview of morphological changes of calcium oxalate crystals, which were grown without and with the addition of NDGA at different concentrations. A gel diffusion technique was employed for sample preparation. Our results from both Raman and FTIR spectroscopies demonstrate that no structural transformation from a monohydrate to dehydrate occurs upon crystallization with NDGA, as we previously reported for the use of the natural plant infusion. Calculi synthesized with NDGA shows a distorted monohydrate morphology. Different effects inhibitory to calcium oxalate calculi formation are observed and analyzed here using chemical and natural extracts. If magnesium is the key to this difference, this study confirms its importance, not only in hundreds of metabolic pathways, but also in nephrological ones.