Synthesis, DFT, electrochemical, biological and DNA-interaction studies of a novel copper(II) complex of salicylic acid and N-tosyl substituted benzimidazole

Experimental and Molecular Docking Studies on the Interaction of a Water-Soluble Pd(II) Complex Containing β-Amino Alcohol with Calf Thymus DNA

The interaction of water-soluble and fluorescent [Pd (HEAC) Cl₂] complex, in which HEAC is 2-((2-((2-hydroxyethyl)amino)ethyl)amino) cyclohexanol, with calf thymus DNA (ct-DNA) has been studied. This study was performed using electronic absorption and fluorescence emission spectroscopies, cyclic voltammetry and circular dichroism analyses, dynamic viscosity measurements, and molecular docking theory. From hypochromic effect observed in ct-DNA absorption spectra, it was found that the Pd(II) complex could form a conjugate with ct-DNA strands through the groove binding mode. The K_b values obtained from fluorescence measurements clearly assert the Pd(II) complex affinity to ct-DNA. The fluorescence quenching of the DNA-Hoechst compound following the successive additions of the Pd(II) complex to the solution revealed that the Pd(II) complex is located in the ct-DNA grooves, and Hoechst molecules have been released into solution; moreover, the resulting measurements from relative viscosity authenticate the Pd(II) complex binding to the grooves. Negative quantities of thermodynamic parameters imply that the Pd(II) complex binds to ct-DNA mainly by the hydrogen bonds and van der Waals forces; also, the Gibbs-free energy changes show the exothermic and spontaneous formation of the Pd(II) complex-DNA system. The electrochemical behavior of the Pd(II) complex in the attendance of ct-DNA was investigated using the cyclic voltammetry method (CV). Several quasi-reversible redox waves were observed along with increasing the anodic/cathodic peak currents, as well as a shift in anodic/cathodic peak potentials. Circular dichroism (CD) observations suggested that the Pd(II)-DNA interaction could alter ct-DNA conformation. The results of molecular modeling confirmed that groove mechanism is followed by the Pd(II) complex to interact with ct-DNA.

Spectroscopic and electrochemical approaches for the analysis of interaction between textile dye 231 and salmon sperm DNA

DNA is one of the most critical targets for many artificial agents listed as carcinogens. Most of them irreversibly bind to the DNA and induce genome mutation; therefore, it is vital to study the nature of binding of these molecules to anticipate their toxicity. The interaction between the textile dye reactive red 231 and salmon sperm double-stranded DNA (ss-dsDNA) was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and ultraviolet-visible spectroscopy (UV–vis spectroscopy). Changes in the anodic current signals of the dye were observed in the presence and absence of ss-dsDNA at a glassy carbon electrode (GCE) using CV. The diffusion coefficient (D) was found to be 2.2 × 10–7 and 9.5 × 10–8 cm2 s−1 from the CV data for the free dye and dye-DNA complex, respectively. Electrochemical and UV–vis spectroscopy indicated 1:1 complex formation of the dye with DNA. The binding constant (kb) between the dye and DNA was calculated to be 5.4 × 105 M–1 and 4.9 × 105 M–1 at pH 4.0 using CV and UV–vis spectroscopy, respectively. Overall, these results suggest that the dye binds to DNA through the combined effect of intercalation and electrostatic interactions. DNA damage was also detected through changes in the voltammetric behaviour of the dye.