Pallidifloside D, a saponin glycoside constituent from Smilax riparia, resist to hyperuricemia based on URAT1 and GLUT9 in hyperuricemic mice.

BACKGROUND

The roots and rhizomes of Smilax riparia (SR), called "Niu-Wei-Cai" in traditional Chinese medicine (TCM), are believed to be effective in treating hyperuricemia and gout symptoms. This study was designed to isolate a saponin glycoside named pallidifloside D from the total saponins of Smilax riparia and to examine its effect in reducing serum uric acid levels in a hyperuricemic mouse model induced by potassium oxonate.

METHODS

We examined the effects of pallidifloside D treated with 5, 10 and 20mg/kg on serum uric acid levels (SUA), Serum creatinine (SCr) and blood urea nitrogen (BUN) levels in a hyperuricemic mouse. A colorimetric method was used to evaluate the effects of pallidifloside D on the XOD activities, and Western Blotting analysis were carried out to observe protein levels of mURAT1, mGLUT9 and mOTA1 in hyperuricemic mice after treatment with pallidifloside D.

RESULTS

The levels of serum uric acid levels (SUA) were suppressed significantly with dose-dependence by pallidifloside D treated with 5, 10 and 20mg/kg (p<0.05, p<0.01 and p<0.01 respectively). Pallidifloside D could down-regulate the expression levels of renal mURAT1 protein in hyperuricemic mice in a dose-dependent manner (p<0.05, p<0.01, and p<0.001 respectively), and the protein levels of mGLUT9 could be down-regulated with dose-dependence (p<0.05 and p<0.01 respectively) by pallidifloside D at the dose of 10 and 20mg/kg.

CONCLUSIONS

These results suggest that pallidifloside D possesses a potent uricosuric effect in hyperuricemic mice through decreasing renal mURAT1 and GLUT9, which contribute to the enhancement of uric acid excretion and attenuate hyperuricemia-induced renal dysfunction.