Hypouricemic effect of flaccidoside II in rodents.

To investigate the effect of flaccidoside II on the serum uric acid levels in hyperuricemic rodents. Both mice and rats were injected intraperitoneally with potassium oxonate to induce hyperuricemia. Different dosages of flaccidoside II were orally administrated to hyperuricemic and normal rodents for 7 days, respectively. Liver xanthine oxidase (XOD) activities in hyperuricemic mice were determined using the colorimetric method. Acute toxicity of flaccidoside II was also evaluated in mice. Allopurinol, as a positive control, was administered under the same treatment scheme. The results showed that flaccidoside II (32, 16 and 8 mg/kg) could significantly lower serum uric acid levels in hyperuricemic mice. Flaccidoside II (24, 12 and 6 mg/kg) could also markedly lower serum uric acid levels in hyperuricemic rats. However, unlike allopurinol, oral administration of flaccidoside II did not produce any observable hypouricemic effect in normal animals. Flaccidoside II at the dose of 32 mg/kg significantly suppressed XOD activities in the liver of hyperuricemic mice, while at doses of 16 and 8 mg/kg flaccidoside II did not show a significant effect on XOD activities. In addition, flaccidoside II (300 mg/kg) has no or less toxicity than allopurinol in mice. These findings demonstrate that flaccidoside II exhibits anti-hyperuricemic activity in hyperuricemic animals.