橙皮素-铜(II)配合物对黄嘌呤氧化酶的抑制作用及其降尿酸机制研究

嘌呤氧化酶（XOD）能够催化黄嘌呤氧化产生尿酸，体内过高的尿酸将导致高尿酸血症，黄酮类金属配合物因其独特的结构和功能特性而广受关注。我们前期发现，橙皮素-铜(II)配合物有很强的体外XOD抑制活性，但其抑制机制及体内降尿酸作用机理尚不明确。本项目拟以橙皮素为原料，合成橙皮素-铜(II)配合物，采用现代仪器分析手段结合计算机模拟技术，通过研究配合物对XOD的抑制动力学、结合性质、结合位点及其诱导XOD分子结构的变化对酶结合底物的影响，诠释配合物抑制XOD活性的分子机制；并进一步建立高尿酸血症小鼠模型，通过探究配合物对小鼠血清尿酸等生化指标的干预、对肝脏XOD、ADA和5’-NT等生物酶的抑制及对肾脏尿酸转运蛋白URAT1、GLUT9和OAT1mRNA表达的调控，阐明其降尿酸作用及机理，为探寻XOD新型抑制剂提供新思路，为橙皮素-铜(II)配合物作为降尿酸食品功能因子或药物的研发提供理论基础。

Xanthine oxidase (XOD) can catalyze the oxidation of xanthine to produce uric acid, and the excessive uric acid in vivo will cause hyperuricemia. The metal complexes of flavonoids have attracted widespread attention due to their unique structures and functional properties. Our previous studies found that the hesperetin−copper (II) complex has a strong inhibition activity on XOD in vitro, but its inhibitory mechanism on XOD and lowering uric acid mechanism in vivo are still unclear. This project intends to synthesize and characterize the hesperetin−copper (II) complex using hesperetin as a raw material, and a combination of modern instrumental analysis techniques and computer simulation will be used to clarify the molecular mechanism of the complex inhibiting XOD activity through exploring the inhibition kinetics of the complex on XOD, binding properties and binding sites between hesperetin−copper (II) complex and XOD as well as the effects of XOD structure change induced by the complex on the binding between the enzyme and substrate. Moreover, a hyperuricemia mice model will be further established, and then the intervention of hesperetin−copper (II) complex on serum uric acid and other biochemical indexes will be determined, the inhibition of the complex on liver XOD, ADA and 5'-NT, and regulation of the complex on the expression of renal uric acid transport proteins including URAT1, GLUT9 and OAT1 in the mice will be investigated to elucidate its effect and mechanism of lowering serum uric acid level. The results of this project may provide new idea for exploring novel inhibitors of XOD and offer a theoretical basis for the research and development of the hesperetin−copper (II) complex as a food functional factor or drug with lowing uric acid function.