荧光光谱法研究三种黄酮类化合物与BSA的相互作用

Study on the Interaction of Three Flavones with BSA by Means of Fluorescence Spectroscopy

用荧光光谱法研究了黄酮类化合物高良姜素(Galangin)、山萘酚(Kaempferol)、槲皮素(Quercetin)和牛血清白蛋白(BSA)之间的相互作用,测定了这三种化合物与BSA的结合常数和结合位点数,探讨了其荧光猝灭机制。根据热力学参数确定了三种化合物与BSA之间的作用力类型,运用Foerster's偶极-偶极非辐射能量转移原理测定了与牛血清白蛋白的结合距离。结果表明,高良姜素、山萘酚、槲皮素等三种黄酮化合物能够使牛血清白蛋白的荧光猝灭,各化合物与BSA自发地发生了结合,形成了新的加合物(Adduct)或缀合物(Conjugate)。其荧光猝灭过程是疏水作用力为主导的静态猝灭过程,BSA与各化合物之间发生了非辐射能量转移。三种黄酮化合物分子中随B环上的羟基数增加,与BSA的结合力增强。

The interactions between Bovine serum albumin and three flavones, galangin, kaempferol and quercetin were studied by means of fluorescence spectroscopy. The fluorescence intensity of BSA exhibited remarkable decrease along with appreciable red-shift of its maximum emission wavelength upon addition of the three compounds, respectively. The respective Binding constant Ko and number of binding sites of each compound were measured, and the quenching mechanism was proposed. Based on the thermodynamic parameters, the binding of each compound with BSA proceeds spontaneously, and was mainly dominated by hydrophobic forces. The binding distance between each and BSA was obtained by Foerster＇s dipile-dipile non-radiation energy transfer mechanism. The structure of flavonols influences significantly the binding process and the affinity increased with the numbers of -OH groups on the Bring.