Effect of Kampo extracts on urinary stone formation: an experimental investigation.

Abstract

OBJECTIVE: To examine the effects of Kampo extracts on the process of urinary stone formation. METHODS: A total of 14 Kampo extracts (10 μg/mL) were examined in vitro by assessing whether they could inhibit two critical steps in the early process of calcium oxalate stone formation, namely crystal aggregation and crystal adhesion to the renal tubular epithelium of Madin-Darby canine kidney cells. The inhibitory effect of the extracts on stone formation was examined by using a rat model. RESULTS: Sanshishi and Takusha showed a strong inhibitory effect on the calcium oxalate monohydrate crystal aggregation (84.5% and 64.2%, respectively) and on the crystal adhesion to Madin-Darby canine kidney cells (88.2% and 54.6%, respectively). As pretreatment of Madin-Darby canine kidney cells with these two Kampo extracts did not show any inhibitory effect on crystal adhesion, they were considered to mainly affect the crystal surface to block crystal adhesion to Madin-Darby canine kidney cells. Gorin-san, containing both Sanshishi and Takusha, showed significantly stronger inhibitory activities at lower concentrations compared with Chorei-to, which contains Takusha. Finally, Sanshishi showed a prophylactic effect on calcium oxalate crystal deposition in the rat model. CONCLUSIONS: These findings suggest that Gorin-san, which contains Sanshishi and Takusha, might be used for the prophylaxis of urolithiasis in humans.