Effect of Dioscorea tokoro Makino extract on hyperuricemia in mice

Purpose: To investigate the anti-hyperuricemic effect of Dioscorea tokoro Makino extract (DTME) in potassium oxonate-induced hyperuricemic mice. Method: The effect of DTME was investigated in the hyperuricemic mice induced by potassium oxonate. DTME. The extract was administered to the mice daily at doses of 220, 440 and 880 mg/kg for 10 days; allopurinol (5 mg/kg) was given as positive control. Serum and urine levels of uric acid and creatinine were determined by colorimetric method. Simultaneously, protein levels of urate transporter 1 (URAT1) and organic anion transporter 1 (OAT1) in the rat kidney were analyzed by Western blotting. Results: Compared with control, a high dose of DTME inhibited xanthine oxidase (XOD) activity in both serum (18.12 ± 1.33 U/L) and in liver (70.15 ± 5.20 U/g protein) (p < 0.05); decreased levels of serum uric acid (2.04 ± 0.64 mg/L) (p < 0.05), serum creatinine (0.35 ± 0.18 μmol/L) and blood urea nitrogen (BUN) (8.83 ± 0.71 mmol/L) (p < 0.05). Furthermore, the extract increased levels of urine uric acid (38.34 ± 8.23 mg/L), urine creatinine (34.38 ± 1.98 mmol/L), down regulated of URAT1 and up regulated of OAT1 protein expressions (p < 0.05) in the renal tissue of hyperuricemic mice. Conclusion: DTME improves renal dysfunction in rats by regulating renal urate transporters in hyperuricemic rats. This may find therapeutic application in antihypertensive therapy.