香豆素类中药有效成分与牛血清白蛋白结合的构效关系

本文主要用荧光光谱(FS)、 紫外光谱(UV)从药物分子结构角度研究五种香豆素类中药有效成分CⅠ~CⅤ与牛血清白蛋白(Bovine Serum Albumin, BSA)结合时的构效关系.

Structure-performance Relationship of some Chinese Herb Components Containing Structural Unit of Coumarin During Binding to Bovine Serum Albumin

The interaction between bovine serum albumin(BSA) and five active components of Chinese Herb CⅠ-CⅤ containing structural unit of coumarin was investigated by ultraviolet(UV) and fluorescence spectroscopy(FS). The intrinsic fluorescence of BSA was quenched by pharmaceuticals via forming pharmaceutical-BSA complexes. The quenching mechanism is mainly a combination of static quenching with  nonradiative energy transfer. The parameters of pharmaceutical-BSA binding process, such as statistic quenching constant KP, the apparent association constant KA, the value of binding site n, the efficiency of energy transfer E, the spatial distance r  and ΔG were obtained. The above parameters disclose the structural-performance relationship of pharmaceutical-BSA interaction as follows. The process of pharmaceutical-BSA binding is promoted strongly by both 4-methyl and 6-hydroxyl in coumarin molecule, but the latter must endure simultaneously some adverse effects caused by increment of molecular polarity and stereo hindrance. Decreasing the polarity of 7-substituent group and increasing the volume of substituting group destroys the pharmaceutical-BSA binding, and the effect is almost totally opposite to that of 6-hydroxyl.