红景天苷与DNA的结合作用研究

Studies on the Interaction of Salidroside with Calf Thymus DNA

在pH=7.4的生理酸度条件下,采用荧光光谱和紫外-可见光谱法,并结合I-效应、离子强度的影响、DNA熔点及粘度测定等实验手段,研究了红景天苷与小牛胸腺DNA的相互作用。结果表明,DNA对红景天苷的内源荧光有明显的猝灭作用,猝灭过程为静态猝灭。由荧光猝灭实验数据,计算出不同温度下红景天苷与DNA之间作用的结合常数和热力学参数,推测疏水作用是两者结合的主要驱动力。KI猝灭实验发现,DNA对红景天苷有明显的保护作用,红景天苷的存在使得DNA的熔点升高、粘度增大,NaCl浓度的增加,DNA-红景天苷体系荧光强度无明显变化。上述实验现象表明,红景天苷以嵌插方式作用于DNA的结合位点。

The interaction between salidroside and calf thymus DNA in physiological buffer （pH=7.4） was investigated by fluorescence spectroscopy,UV-Vis spectrophotometry,I-fluorescence quenching effect,influence of ion strength,viscosity measurements and DNA melting techniques,respectively.The results showed that there was a strong fluorescence quenching of salidroside induced by DNA,and the probable mechanism was a static quenching.The binding constants K and thermodynamic parameters（△H,△S and △G） were calculated at three different temperatures,which showed that the binding of salidroside to DNA was driven mainly by hydrophobic interaction.KI fluorescence quenching experiment indicated that DNA caused obvious protection to salidroside.The relative viscosity and value of melting temperature of DNA increased in the presence of salidroside.Based on the above results,it could be inferred that the binding of salidroside with DNA was an intercalation binding.