蒽醌及黄酮类化合物与人血清白蛋白的结合反应研究

Studies on the Binding of Anthraquinones and Flavonoids to Human Serum Albumin

用荧光光谱法研究了大黄素、黄酮、栎精、柚皮甙、黄芩甙和龙胆苦甙等化合物与人血清白蛋白（ＨＳＡ）的结合反应。发现除龙胆苦甙外，其余化合物对ＨＳＡ的荧光有很强的猝灭作用。从荧光猝灭结果求得了它们与ＨＳＡ的结合常数，表明这些化合物与ＨＳＡ的结合能力随其所含极性基团的增多而减弱。根据Ｆｏｒｓｔｅｒ非辐射能量转移机理，求出了第一结合部位与ＨＳＡ分子中２１４－色氨酸残基的距离，由此提出了形成复合物的结构模型。并对油酸钠与大黄素、黄酮的竞争结合反应和黄芩甙与大黄素、栎精之间的竞争结合反应进行了研究。

The binding of emodin, flavone,quercetin, naringin, baicalin and gentiopicrin to human serum albumin (HSA) was studied using fluorescence spectroscopy. It was shown that these compounds have a powerful ability to quench the HSA fluorescence via a nonradiative energy transfer mechanism except gentiopicrin. The fluorescence quenching data was analyzed according to Scatchard equation,and the binding constants in the range 104 t0 5×105L/mol were obtained. It was found that the affinity of these compounds to HSA is positively related to their hydrophobicity. By use of a spectra overlap integral between the absorption spectrum of these compounds and the emission spectrum for HSA, the distance of Trp-214residue to the first binding site of these compounds was estimated. In addition, the competition binding of oleate with emodin and flavone, baicalin with emodin and quercetin was monitored by fluorescence quenching. The binding mechanism was discussed in brief and an allosteric domain model of emodin-HSA complex was postulated from above results.