木犀草素与DNA相互作用的电化学研究

Investigation of the Electrochemical Behavior of the Interaction of Luteolin with DNA

木犀草素在0．04mol／L B～R（pH4．00）缓冲溶液中于＋0．478V（vs.SCE）和＋0．450V（vs.SCE）有一对氧化还原峰。当向该溶液中加入DNA分子后，通过比较电化学参数转移系数α和表观电子传递速率常数κs的变化，可知木犀草素嵌入DNA碱基对间形成了非电活性的超分子化合物从而使得峰电位正移，峰电流下降；通过二者的紫外吸收光谱对其嵌入作用进行了验证。研究发现木犀草素的氧化峰电流，Ipa与DNA质量浓度在2～12mg／L的范围内基本呈线性关系，线性回归方程为Ipa（10^-5 A）=8．68—0．322ρDNA（mg／L），相关系数r为0．989；建立了定量检测DNA的方法。并求得木犀草素和DNA嵌入作用的结合常数β=3．02×10^11，结合数m=2。

A pair of voltmmetric peaks for the redox reaction of luteolin in the B - R buffer solution was found with the anodic peak potential of ＋ 0. 478 V （vs. SCE ） and the cathodic peak potential of ＋0. 450 V（vs. SCE）. After the addition of DNA, the peak current decreased due to the intercalation of luteolin with DNA by forming an electrochemical inactive supramolecular complex DNA - 2Lu. The electrochemical parameters such as charge coefficient α and standard electron transfer rate constant κs in the absence and presence of DNA were estimated. The combination number m of the interaction of 2 and the combine constant β of 3.02 × 10H were also calculated, and the results were confirmed by ultraviolet -visible spectra. The oxidation peak current showed a linear relationship with the DNA concentration in the range of 2 -12 mg/L, and the linear regression equation was Ipa （10^-5 A） = 8.68 - 0. 322ρDNA （mg/L） with the correlation coefficient of 0. 989. Based on this, a new voltammetric method for the determination of DNA was established.