Herbal remedies are increasingly being considered as suitable long-term treatments for renal dysfunction. The objective of the present study was to investigate the effect of some herbal extracts, all previously identified in published studies as influencing kidney stone formation, on the crystallization characteristics of calcium oxalate (CaOx) in synthetic urine (SU). Five herbal extracts were selected for the study: Folium pyrrosiae, Desmodium styracifolium, Phyllanthus niruri, Orthosiphon stamineus and Cystone(®). Concentrated stock solutions of each herbal extract were prepared and were tested at their recommended dosages in in vitro crystallization studies in SU. CaOx crystallization experiments were performed in which the metastable limit (MSL), average particle size, and nucleation and growth rates were determined. The CaOx MSL of SU was unaltered by the five herbal extracts. Three of the herbs (Desmodium styracifolium, Orthosiphon stamineus and Cystone(®)) significantly reduced the average particle size of precipitated crystals relative to undosed SU. All of the extracts increased the rate of nucleation and decreased the rate of growth significantly in SU. Cystone(®) showed the greatest effect on the measured risk factors. It is concluded that all of the herbs have the potential to serve as inhibitors of calcium oxalate stone formation and warrant investigation in clinical trials.

Fructans isolated from Agave americana grown in South Africa are currently used for spirit production. Structural studies on water-soluble fructans were performed to facilitate the development of other applications including its use as a prebiotic. Acid hydrolysis followed by HPAEC-PAD analysis confirmed that the fructan was composed of glucose and fructose, and size analysis by HPAEC-PAD and size exclusion chromatography indicated that the saccharides have a DP range from 6 to 50. An average DP of 14 was estimated by (1)H NMR analysis. Linkage analysis and ESI-MS studies suggest that A. americana has a neofructan structure consisting of a central sucrose to which (2 → 1)- and (2 → 6)-linked β-D-Fruf chains are attached. The (2 → 1)-linked units extend from C-1 of Fru and C-6 of glucose, whereas the (2 → 6)-linked β-D-Fruf units are attached to C-6 of the central Fru. This structure accounts for the presence of equimolar amounts of 1,6-linked Glu and 1,2,6-linked Fru found in linkage analysis and the multiplicity of the NMR signals observed. Detailed ESI-MS studies were performed on fructan fractions: native, periodate oxidized/reduced, and permethylated oligomers. These derivatizations introduced mass differences between Glc and Fru following oxidation and between 1,2-, 1,6-, 2,6-, and 1,2,6-linked units after methylation. Thus, ESI-MS showed the presence of a single Glc per fructan chain and that it is predominantly internal, rather than terminal as found in inulin. These structural features were confirmed by the use of 1D and 2D NMR experiments.

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Kidney stone disease occurs throughout the world. Conservative treatments involving herbal preparations have been used in traditional Chinese medicine. In vitro studies have suggested that Folium pyrrosiae (FP) has therapeutic potential in this context. The present study was undertaken to investigate the effects of ingested FP on urinary thermodynamic and kinetic risk factors for calcium oxalate (CaOx) stone formation in subjects from two different population groups. Healthy white (n = 9) and black (n = 9) males ingested 1.5 g FP each day for 7 days. 24 h urines (baseline and day 7) and blood samples (baseline and day 3) were collected. Urines were analyzed for lithogenic risk factors and were subjected to CaOx crystallization experiments in which the metastable limit (MSL), particle size-volume distribution and crystal deposition kinetics were determined. Urine composition values were used to calculate the relative supersaturation (RS) of CaOx and other urinary salts. Blood samples were analyzed for liver enzymes to monitor the safety of the protocol. Food diaries were recorded on days 0 and 7. Data were analyzed statistically using standard software. Nutrient intakes and the concentration of liver enzymes did not change during the study. No side effects were reported. There were no statistically significant differences in any of the thermodynamic (RS, MSL) or kinetic (particle volume-size distribution, crystal deposition rate) risk factors for CaOx stone formation in either of the groups following ingestion of FP relative to baseline values. FP does not have potential as a therapeutic agent in the management of CaOx kidney stone disease.