荧光光谱法测定黄芪甲苷及环黄芪醇与牛血清白蛋白相互作用  

Fluorescence Spectroscopic Studies on Interaction of Astragaloside IV and Cycloastragenol with Bovine Serum Albumin

作　　者：罗志强[1] 张玉杰[1] 孙青[1] 魏宝红[1] 刘星[1] 王雄飞[1] 袁瑞娟[1] 

机构地区：[1]北京中医药大学中药学院,北京100102

出　　处：《中国实验方剂学杂志》2013年第16期123-127,共5页Chinese Journal of Experimental Traditional Medical Formulae

基　　金：教育部大学生创新性实验计划项目(201210026034)

摘　　要：目的:采用荧光光谱法研究黄芪甲苷及环黄芪醇与牛血清白蛋白(BSA)的相互作用机制。方法:固定BSA浓度,依次加入不同浓度的黄芪甲苷或环黄芪醇,扫描其荧光猝灭光谱及同步荧光光谱。结果:黄芪甲苷和环黄芪醇均能对BSA的荧光发生淬灭,猝灭类型属于静态猝灭;在293 K下,黄芪甲苷和环黄芪醇与BSA的结合常数分别为1.35×104,8.51×104L.mol-1,结合位点数n分别为0.726 4,0.731 2,在310 K温度下,二者与BSA的结合常数均略有下降。二者与BSA的结合过程均属于焓变小于零、熵变大于零、吉布斯自由能小于零的自发过程,与BSA的作用力类型为静电作用为主。同步荧光光谱显示二者均对色氨酸残基构象产生影响,对酪氨酸残基构象影响较小。结论:本实验阐明了黄芪甲苷和环黄芪醇与牛血清白蛋白的作用机制,为其进一步用药提供了理论依据。Objective： To clarify the interaction mechanism of astragaloside IV and cycloastragenol with bovine serum albumin （BSA） by fluorescence spectroscopy. Method： Scanning the fluorescence quenching and synchronous spectrum through adding astragaloside IV and cycloastragenol to the solution of BSA. Result： The fluorescence quenching mechanism of astragaloside IV and cycloastragenol was static quenching. Under 293 K, the binding constants （KA ） of astragaloside IV and cycloastragenol were 1.35 × 10^4 and 8.51 × 10^4 L · mol^-1, respectively. And the numbers of binding sites were 0. 726 4 and 0. 731 2, respectively. Under 310 K, the binding constants of astragaloside IV and cycloastragenol were both decreased. The thermodynamic parameters of astragaloside IV and cycloastragenol with BSA were △H 〈 0, △S 〉 0, and △G 〈 0, the interaction of astragaloside IV and cyeloastragenol with BSA were driven mainly by electrostatic interaction. The results of synchronous spectrum showed that both the astragaloside IV and cycloastragenol affected the space conformation of tryptophane. But the space conformation of tyrosine was not affected by astragaloside IV and cycloastragenol. Conclusion： The interaction mechanism of astragaloside IV and cycloastragenol with BSA was clarified by fluorescence spectroscopy. It can supply theoretical supports for the rational administration of astragaloside IV and cycloastragenol.

关 键 词：黄芪甲苷 环黄芪醇 牛血清白蛋白 荧光光谱 作用机制 

分 类 号：R284.1[医药卫生—中药学]