Pu-erh ripened tea resists to hyperuricemia through xanthine oxidase and renal urate transporters in hyperuricemic mice

- Pu-erh ripened tea has the effects of reducing uric acid levels in serum.
- The tea inhibits xanthine oxidase and adenosine deaminase activities in liver.
- The tea down-regulates renal mGLUT9 and mURAT1 protein and mRNA expression.
- Its mechanisms are inhibiting uric acid production and renal urate reabsorption.

To investigate the effects of Pu-erh ripened tea on lowering uric acid levels and identify its possible mechanisms, three different doses of the tea, with allopurinol as a positive control, were administered intragastrically to hyperuricemic mice. Hyperuricemia was induced in the mice by oral administration of potassium oxonate for 7 days. Serum levels of uric acid, liver xanthine oxidase (XOD) and adenosine deaminase (ADA) activities, and expression of renal mURAT1, mGLUT9, mOAT1 and mOCT1 protein and mRNA were measured. Pu-erh ripened tea, at all doses, significantly lowered serum uric acid levels. At the high and medium doses, it also markedly inhibited liver XOD and ADA activities. Furthermore, mURAT1 and mGLUT9 expression levels were significantly down-regulated by Pu-erh ripened tea treatment. These results suggested that Pu-erh ripened tea can resist to hyperuricemia, possibly by inhibiting, concurrently, uric acid production and renal urate reabsorption.