Formation and Growth Inhibition of Calcium Oxalate Crystals by Takusha (alismatis Rhizoma)

The aim of this study was to examine the effect of Takusha (Alismatis rhizoma), a Kampou medicine, on the formation, growth and aggregation of calcium oxalate (CaOx) crystals by a seed crystal system, an undiluted urine system and a continuous flow crystallizer system. In the seed crystal method using a metastable solution, the inhibitory effect on aggregation and growth of CaOx crystals was calculated using a Coulter counter. Takusha had a strong inhibitory effect on the aggregation and growth when the concentration was above 10 mg/ml. In measuring the metastable limit by the microplate method, Takusha had a mild inhibitory effect on the formation of crystals above the concentration of 1000 mg/ml. In the undiluted urine system, the formation and growth of CaOx crystals precipitated in response to a load of sodium oxalate were measured. Takusha had a strong inhibitory effect at concentrations of 100 to 1000 mg/ml. In the continuous flow crystallizer system, nucleation rate, growth rate and crystal mass were decreased in proportion to the increase of added Takusha. These results suggest that Takusha strongly suppressed each step of crystal formation, growth and aggregation of CaOx crystals, and therefore, may be a useful drug for preventing CaOx urolithiasis.