Hypouricemic and nephroprotective effects of total flavonoids from the residue of supercritical CO2 extraction of Humulus lupulus in potassium oxonate-induced mice

Total flavonoids of Humulus lupulus (TFHL) were prepared using ethanol extraction, liquid-liquid partition and purification with polyamide resin. Different dose of TFHL were orally administered to normal and hyperuricemic mice for 7 days. The xanthine oxidase (XOD) inhibitory activity and hypouricemic effects of TFHL on potassium oxonate-induced hyperuricemic mice were examined. The TFHL showed very potent XOD inhibitory activity with IC50=66.8 mu g/mL. At a single oral dose of 100mg/kg TFHL, the serum uric acid levels of hyperuricemic mice significantly decreased (P<0.01) compared with a hyperuricemic control group, and the XOD activity was inhibited by 22%. Moreover, TFHL has a protective role against potassium oxonate-induced renal damage in mice. The results suggested that TFHL could be used as a promising drug or ingredient for treatment of hyperuricemia and gout.