香豆素类中药有效成分与牛血清白蛋白结合的构效关系

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.