Experimental Studies On Development Of New Anti-hyperuricemia Drugs Targeting Xanthine Oxidase

Aim To improve the technology system for screening xanthine oxidase(XOD)inhibitors,and to apply this system for discovery some lead compounds for the treatment of hyperuricemia.Methods Based on the principle that the end product uric acid shows an absorption peak at wavelength 293nm,the reaction conditions,like substrate concentration,etc.were regulated for improving the efficiency of the reaction in vitro.The hyperuricemia(HUA)mouse model was induced by oteracil potassium in vivo.For screen the leading compounds in vitro,the inhibition of samples on XOD activity was measured.The IC50 value of the samples,which can inhibit XOD activity over 80%at dose of le-5 mol·L-1.was determined.Then,the effects of the samples,which show perfect inhibitory activity on XOD in vitro,on the serum uric acid level was evaluated in HUA model mice.The indexes,like serum uric acid,serum XOD activity,renal function,XOD activity in tissues,etc.were measured with the commercial kits,respectively.Results In the method for screening XOD inhibitors in vitro,the reaction conditions including XOD extracted from milk 3 U·L-1,Xanthine(XA)50μmol·L-1,pH=7.4,shaking at 37℃ for 20 min with the positive control febuxostat(FBX,le-7 mol·L1)were chosen.In the HUA model mice,the levels of serum uric acid were increased significantly induced by oteracil potassium 300 mg·kg-1](sc);the XOD activities in serum and in small intestine,heart,liver,lung,kidney and spleen were no significant changed,respectively,compared with those age-matched normal control mice.Utilizing this technology system,we screened 947 samples by XOD inhibition,and found 6 active compounds with IC50 values from 10-10 to 10-6 mol·L-1.Among them,the IC50 value of sample CC15009 is the lowest.After administration with sample CC15009(po)in HUA model mice,the serum uric acid level decreased significantly in a dose-dependent manner;and the minimum effective dose was 0.1 mg·kg-1(po).Moreover,serum XOD activity was also inhibited by sample CC 15009 in a dose-dependent manner in HUA mice;and no significant renal injury was found.Structural modification of lead compound CC 15009,we found 22 active compounds on XOD inhibition in vitro,and 2 active compounds on reducing serum uric acid level in HUA mice.But their activities in vitro and in vivo were lower than sample CC 15009.Conclusions By improving and utilizing the technology system of XOD inhibitors,the lead compound CC 15009 was found,and is developing to a potential anti-hyperuricemia drug.