香叶木素抑制黄嘌呤氧化酶活性及联用研究

Inhibition of Xanthine Oxidase Activity and Its Combination with Diosmetin

香叶木素、木犀草素、白杨素和芹菜素结构的主要区别就是B环中取代基不同,通过抑制黄嘌呤氧化酶(XO)活性实验可得R_(1)位置对酶的抑制效果强于R_(2);另外,当R_(1)、R_(2)基团同时存在,R_(1)为亲水性基团,R 2为疏水性基团更有利于抑制剂降低酶活性;香叶木素抑制酶效果最好。通过紫外和荧光光谱法可判断香叶木素与黄嘌呤氧化酶的抑制机理:与铁离子反应实验可得香叶木素能与XO的Fe-S催化活性中心的Fe^(2+)反应,从而阻断尿酸生成的电子传递链;三维和同步荧光实验结果证明香叶木素主要是改变酶色氨酸残基周围微环境从而实现抑制酶的效果。联合抑制实验证明抑制剂与别嘌醇可以协同抑制黄嘌呤氧化酶。这为寻找新型安全无毒的黄嘌呤氧化酶抑制剂提供新思路,具有重要意义。

The main difference of the structure of diosmetin,luteolin,albumin and apigenin is the difference of the substituents in the B ring.The inhibitory effect of R_(1) on the enzyme was stronger than that of R_(2) through the activity of inhibiting xanthine oxidase(XO).In addition,when R_(1) and R_(2) groups were present at the same time,R_(1) was a hydrophilic group and R_(2) was a hydrophobic group,which was more conducive to the inhibitor to reduce the enzyme activity.Diosmetin had the best inhibitory effect on enzymes.The inhibition mechanism of diosmetin and xanthine oxidase could be determined by UV and fluorescence spectroscopy.The reaction experiment with iron ion showed that geranyl could react with Fe^(2+)of Fe-S catalytic active center of XO.The results of three-dimensional and synchronous fluorescence experiments showed that diosmetin mainly changed the microenvironment around tryptophan residues of the enzyme to experiment the effect of inhibiting the enzyme.Combined inhibition experiments showed that the inhibitor and allopurinol could synergically inhibit xanthine oxidase.It was of great significance to find new safe and non-toxic xanthine oxidase inhibitors.