四种黄酮类化合物与牛血清白蛋白相互作用的光谱分析

在人体生理pH条件下,利用紫外吸收光谱和荧光光谱研究了槲皮素(QUE)、大豆甙元(DAI)、4′,7-二甲氧基-3′-异黄酮磺酸钠(DISS)和3′-大豆甙元磺酸钠(DSS)四种黄酮类化合物与牛血清白蛋白(BSA)的相互作用,结合反应机理对其进行了初步探讨;并计算了结合位点数和结合常数.紫外吸收光谱分析结果表明,在pH=7.4条件下,黄酮类化合物中疏水性的苯环与BSA疏水腔中的氨基酸残基发生作用,从而导致药物分子的吸收峰红移,用Scatchard拟合法可求得DAI及DSS与BSA的结合常数.荧光光谱分析结果表明,BSA对DAI、DISS和DSS均有明显的敏化增强效应,计算得到的增强速率常数分别为1.39×1011,7.72×1011和1.93×1012L·s-1·mol-1,并可求得结合位点数和结合常数.

Spectroscopic analysis of interaction between four kinds of flavonoids and bovine serum albumin

The interactions of quercetin （QUE）, daidzein （DAD, 4＇,7-dimethoxy-3r -isoflavone sulfo- nic sodium （DISS）, and 3Cdaidzein sulfonic sodium （DSS） with BSA under human body physiological pH value were investigated using ultraviolet （UV） absorption spectrometry and fluorescence spec- trometry. The binding mechanism was primarily discussed; and the number of binding sites and bind- ing constants were calculated. UV absorption spectroscopic analysis results indicate that, under physi- ological pH value of 7.4, the hydrophobic benzene rings of flavonoids interact with the amino acid resi- dues of BSA hydrophobic cavity thereby resulting in red shift of the absorption peak of drug mole- cules; and the binding constants of DAI and DSS with BSA can be calculated by Scatchard fitting method. Besides, the fluorescence spectroscopic analysis results indicate that BSA can significantly en- hance the sensitization of DAI, DISS and DSS. The enhance rate constants are calculated to be 1.39 5〈 10n , 7.72 X 10n and 1.93 5〈 1022 L s-1 mo1-1 , while the number of binding sites and binding constants can also be calculated.