Electrochemical and computational studies on the interaction between calf-thymus DNA and skin whitening agent arbutin.

The interaction between double-stranded calf thymus DNA (ctDNA) and the skin whitening agent arbutin (AR) examined by applying electrochemical and computational methods for the first time in literature. A single-use pencil graphite electrode via cyclic (CV) and differential pulse voltammetry (DPV) techniques were applied to determine the kinetic and thermodynamic parameters in the absence and presence of ctDNA. To examine the interaction process, oxidation peak currents and potentials of AR were observed prior to the addition of various ctDNA concentrations. The binding constants (KAR-DNA) and Gibbs free energy (ΔG°) values for the AR-DNA complex were determined as 1.82 × 104L/mol and -24.30 kJ/mol at 298 K, respectively. Temperature evaluation of the interaction was examined using thermodynamic parameters (ΔH°: -30.30 kJ/mol and ΔS°: -0.00197 kJ/mol) applying the Van't Hoff equation. The local interaction sites in the molecule structure were determined by applying Fukui functions and second-order perturbation theory in view of potential hydrogen binding centers. The optimized structure of AR was applied with a DNA structure revealing the binding position for AR-DNA complex. Experimental and computational examinations suggested that AR-DNA binds to ctDNA through a minor groove mode via conventional hydrogen bonds, hydrophobic interactions and van der Waals forces.