Comprehensive analysis of mechanism underlying hypouricemic effect of glucosyl hesperidin.

ABSTRACT

Hyperuricemia is caused by hepatic overproduction of uric acid and/or underexcretion of urate from the kidneys and small intestine. Although increased intake of citrus fruits, a fructose-rich food, is associated with increased risk of gout in humans, hesperidin, a flavonoid naturally present in citrus fruits, reportedly reduces serum uric acid (SUA) levels by inhibiting xanthine oxidase (XOD) activity in rats. However, the effects of hesperidin on renal and intestinal urate excretion were previously unknown. In this study, we used glucosyl hesperidin (GH), which has greater bioavailability than hesperidin, to clarify comprehensive mechanisms underlying the hypouricemic effects of hesperidin in vivo. GH dose-dependently decreased SUA levels in mice with hyperuricemia induced by potassium oxonate and a fructose-rich diet, and inhibited XOD activity in the liver. GH decreased renal urate excretion without changes in kidney URAT1, ABCG2 or GLUT9 expressions, suggesting that reducing uric acid pool size by inhibiting XOD decreased renal urate excretion. We also found that GH had no effect on intestinal urate excretion or protein expression of ABCG2. Therefore, we concluded that GH exhibits a hypouricemic effect by inhibiting XOD activity in the liver without increasing renal or intestinal urate excretion. Of note, this is the first study to elucidate the effect of a flavonoid on intestinal urate excretion using a mice model, whose findings should prove useful in future food science research in the area of urate metabolism. Taking these findings together, GH may be useful for preventing hyperuricemia, especially in people with the overproduction type.