Spectroscopic, electrochemical and molecular docking studies of dothiepin and doxepin with bovine serum albumin and DNA base.

Abstract

The interaction of dothiepin (DOT) and doxepin (DOX) with bovine serum albumin (BSA) and a DNA base (adenine) was studied using UV-visible, fluorescence, attenuated total reflection-infra-red (ATR-IR), cyclic voltammetry and molecular docking methods. Strong fluorescence quenching was observed upon interaction of DOT and DOX with BSA/adenine and the mechanism suggested static quenching. Hydrophobic and hydrogen bonding interactions were the predominant intermolecular forces needed to stabilize the copolymer. Upon addition of the drugs: (i) the tautomeric equilibrium structure of the adenine was changed; and (ii) the oxidation and the reduction peaks of the adenine/BSA interaction shifted towards high and low potentials, respectively. In ATR-IR, the band shift of amides I and II indicated a change in secondary structure of BSA upon binding to DOT and DOX drugs. The reduction in voltammetric current in the presence of BSA/adenine was attributed to slow diffusion of BSA/adenine binding with DOX/DOT. The docking method indicated that the drug moiety interacted with the BSA molecule. Copyright © 2016 John Wiley & Sons, Ltd.