槲皮素与牛血红蛋白的相互作用与抗氧化研究

Interaction between Quercetin and Bovine Hemoglobin and Its Antioxidant Ac

采用荧光光谱法、紫外可见吸收光谱法,在模拟生理环境下研究槲皮素(QUE)与牛血红蛋白(BHb)相互作用的热力学行为.荧光光谱结果表明,QUE能有效猝灭BHb的内源荧光,且是QUE与BHb以1∶1结合生成复合物的静态猝灭类型,具有较高的亲和力.通过Van’t Hoff方程计算得到热力学参数(ΔG、ΔH、ΔS),表明QUE与BHb的相互作用过程是一个自发过程,且两者之间的相互作用力以氢键和范德华力为主.Forster偶极-偶极非辐射能量转移结果表明,QUE与BHb内的色氨酸(Trp)残基之间的结合距离为2.09 nm.紫外-可见吸收光谱和同步荧光光谱表明,QUE可导致BHb构象和一些微环境的变化,进而影响BHb的生理功能.QUE与BHb结合显著提升其对DPPH自由基的清除率,且对BHb没有浓度依赖性.

Under simulated physiological conditions,the thermodynamics of the interaction between quercetin(QUE)and bovine hemoglobin(BHb)was studied by fluorescence and ultraviolet-visible absorption spectroscopy.The fluorescence spectra results showed that the quenching of BHb by QUE was a static process.QUE and BHb formed a 1∶1 complex which had a high affinity.The thermodynamic parameters(ΔG,ΔH,ΔS)were obtained by Van't Hoff equation,which showed that the interaction between QUE and BHb was a spontaneous process,the interaction forces were mainly hydrogen bonds and van der Waals forces.Forster dipole-dipole non-radiative energy transfer results showed that the binding distance between QUE and tryptophan(Trp)residues in BHb was 2.09 nm.UV visible absorption spectra and synchronous fluorescence spectra showed that QUE caused conformational and microenvironment changes of BHb,which might affect the physiological function of BHb.The DPPH radical scavenging activity was significantly improved after QUE combined with BHb,but there was no concentration dependence on BHb.