Inhibition and dissolution of calcium oxalate crystals and kidney stones by the extract of Kalanchoe pinnata

Abstract

Kalanchoe pinnata leaves are used in South Asia as a natural kidney stone treatment. In vitro studies were conducted in supersaturated and artificial urine solutions to evaluate the antiurolithic properties of K. pinnata leaf extract on calcium oxalate monohydrate (COM) and surgically extracted kidney stones. Key organic acids present in the plant extract were also examined in artificial urine to investigate inhibition of kidney stone formation. Crystals harvested from inhibition and dissolution experiments were characterized by mass change, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), redox titrations, and conductivity measurements. K. pinnata plant extract significantly inhibited crystal growth mechanisms depending on the extract concentration and supported dissolution. Crystal growth in supersaturated solutions and artificial urine was inhibited by 41 and 15 wt%, respectively, and COM and kidney stone mass decreased by 30 and 18 wt% after five extract washes. Active compounds identified in K. pinnata extract are malic, p-hydroxybenzoic, syringic, and caffeic acids, each demonstrated 2.70 to 4.65 wt% inhibition, which cumulatively accounts for the 15% inhibition observed in synthetic urine. This preliminary study demonstrates that the organic acid content of K. pinnata leaf extract is a crucial component for antiurolithic activity