Electrochemical investigation on interaction between DNA with quercetin and Eu-Qu(3) complex

The interactions of quercetin (Qu) and Eu-Qu(3) Complex with calf thymus DNA were studied using cyclic voltammetry (CV) and double potential step chronocoulometry (DPSCC) at glass carbon electrode (GCE) for the surface method. The method is simple, convenient, reliable, reagent saving. Information such as intrinsic binding constant (K), and binding numbers (n) of bound species per DNA (bp), ratio (K-Ox/K-Red) of the binding constants for the oxidized and reduced forms of a bound species and interaction mode was obtained using dsDNA-modified GCE. Quercetin and Eu-Qu(3) can both bind to DNA, but quercetin binds to DNA mainly by electrostatic attraction and the complex bind to DNA by both intercalation and electrostatic attraction. For the quercetin/ dsDNA-modified GCE systems, a K of (3.80 +/- 0.3) x 10(4) M-1, saturation coverage value (Gamma(s)) of (2.28 +/- 0.2) x 10(-10) mol/cm(2) and n of 1.2 were obtained. For the complex system, a saturation coverage value (Gamma(s)) of 1.65 x 10(-10) mol/cm(2) and n of 1.8 were obtained. (C) 2003 Elsevier Inc. All rights reserved.