槲皮素与牛血清白蛋白的相互作用机理以及影响因素的研究对于生物活性小分子与生物大分子的相互作用方式及其功能改变具有一定理论和实际意义。 运用荧光光谱、 紫外可见光谱、 同步荧光光谱、 自由基清除方法（DPPH和ABTS自由基清除率）, 研究了牛血清白蛋白与槲皮素在水、 二甲基亚砜和乙醇三种不同溶剂中的相互作用方式及其对槲皮素抗氧化性的影响。 结果表明: 槲皮素对牛血清白蛋白有较强的荧光猝灭作用, 且为静态与动态并存的复合猝灭方式, 相互作用力为疏水作用力。 三种溶剂中, 牛血清白蛋白与槲皮素的结合常数和结合位点数由大到小依次为: 水＞二甲基亚砜＞乙醇, 结合距离由大到小依次为: 乙醇＞二甲基亚砜＞水。 根据结合距离的大小可知, 结合作用由强到弱依次为: 水＞二甲基亚砜＞乙醇。 在三种溶剂中牛血清白蛋白的酪氨酸和色氨酸残基同时参与与槲皮素的相互作用。 未结合及结合牛血清白蛋白的槲皮素与DPPH自由基清除率均为30%, 未结合及结合牛血清白蛋白的槲皮素与ABTS自由基清除率相比, 由80%显著降低到70%。 三种溶剂对未结合及结合牛血清白蛋白的槲皮素的自由基清除能力无显著性影响。

Modes and influencing factors of bovine serum albumin (BSA) and quercetin (QUE) interaction will help us understand the interaction mechanisms and functional changes of bioactive small molecules and biomacromolecules. The fluorescence spectroscopy, UV-Vis spectroscopy, synchronous fluorescence spectroscopy, DPPH and ABTS radical scavenging assays were used to investigate the characteristics and antioxidant activity of BSA and QUE interaction in three solvent systems (deionized water, dH2O; dimethyl sulfoxide, DMSO and ethanol, EtOH). The results revealed that QUE had a great ability to quench BSA’s fluorescence in both static and dynamic modes, and that hydrophobic interaction played a dominant role in BSA and QUE interaction in three solvent systems. The binding constant values and binding site numbers between BSA and QUE were in the order of dH2O＞DMSO＞EtOH. The binding distances were in the order of EtOH＞DMSO＞dH2O. On the basis of the binding distance, the binding forces were in the order of dH2O＞DMSO＞EtOH. The synchronous fluorescence spectra demonstrated that QUE interacted with both tyrosine and tryptophan residues of BSA in three solvent systems. Moreover, the DPPH radical scavenging rates of both QUE and BSA-QUE were 30%. While, the ABTS radical scavenging rate of QUE was significantly decreased from 80% to 70% when bound to BSA. No significant difference in antioxidant activity between QUE and BSA-QUE was observed in three solvent systems.