Structural identification of a compound preventing calcium oxalate stone disease

DESCRIPTION (provided by applicant): This project will isolate and identify the chemical and structural composition of a plant compound effective in treating and preventing calcium oxalate kidney stone disease in animal studies. It is estimated that there are about 20 million stone patients in the United States. More than 70% of kidney stones in human subjects are composed mainly of calcium oxalate. There is at present no effective treatment for this segment of stone patients (gt 70%) and consequently this compound holds the exciting possibility of making a substantial impact on the treatment and prevention of this widespread and painful disease. The long-term objective is to have the active compound in a pill form that can be taken orally to prevent further stone formation. The compound also has significant potential for use in removing stone fragments and crystal deposits following lithotripsy thereby reducing/preventing stone recurrence. Our initial studies have clearly demonstrated that oral administratio n of the plant extract was effective in preventing stone formation and crystal deposition in a hyperoxaluric rat model. Furthermore, the extract lowered urinary calcium and oxalate in dogs with stone disease, reducing the relative supersaturation of calciu m oxalate to under saturation. No adverse side effects were observed in any of the animals treated with the extract. These findings represent a major discovery. The major aims of this application are to further purify the active compound and elucid ate the structure. A highly active fraction of the plant extract, potent in inhibiting crystal growth of calcium oxalate in vitro, has been identified and brought to 96% purity by an established procedure. The active compound will be purified from this fra ction and its structure elucidated. This fraction will be further purified using a variety of chromatography techniques as well as extraction and precipitation procedures appropriate to this compound. Purity of the active compound will be confirmed by poly acrylamide gel electrophoresis, high performance liquid chromatography and by nuclear magnetic resonance (NMR). The purified active compound will be submitted to chemical and structural procedures to identify, 1) it's chemical composition by gas chroma tography-mass spectrometry (GC-MS); 2) linkage positions of the individual monomers of the compound by methylation analysis-GC MS; 3) molecular weight determination using matrix assisted laser desorption/ionization time-of-flight mass spec (MALDI-TOF MS) a nd liquid chromatography electrospray ionization mass spec (LC-ESI MS); and 4) the type of anomeric configuration (,), other substituents and sequence of the compound, determined by a number of standard NMR techniques. We anticipate that this novel compou nd will prove effective in the treatment of human subjects which would represent a major advance in the clinical treatment and management of stone disease.