Facile synthesis of chalcone derivatives as antibacterial agents: Synthesis, DNA binding, molecular docking, DFT and antioxidant studies

摘要

A series of beta-chalcones derivatives (1a-11) was synthesized using different substituted amines in basic condition by Claisen-Schmidt condensation reaction. Structural analysis of the synthesized compounds was carried out by various characterization techniques. Antimicrobial properties of the chalcone derivatives (1a-11) were evaluated against different bacterial strains Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica, Staphylococcus pneumoniae and Enterococcus faecalis by disc diffusion method. The pharmacological treatment of chalcones showed that chalcone 1b has promising potential against tested bacterial strains. Ct-DNA was used to study the binding interactions of the potent chalcone derivative 1b by means of absorption spectroscopy, viscosity measurement, fluorescence quenching, cyclic voltammetery and circular dichroism study. Chalcone 1b showed significant binding towards Ct-DNA with intrinsic binding constant (K-b) 1.75 x 10(4)M(-1). Molecular docking study of the target compound was also carried out against B-DNA dodecamer d(CGCGAATTCGCG)(2) and it has been found that chalcone 1b can bind to Ct-DNA via an intercalative mode. For the chalcone derivative 1b and Ct-DNA interaction, static quenching mechanism observed which was further confirmed using time-resolved fluorescence spectroscopy. To optimize the chalcone derivative 1b for HOMO-LUMO energy calculation, Density Functional Theory (DFT) has been used. Time dependent-DFT study has been optimized to generate vertical excitation energies, absorption wavelengths and oscillator strengths of the chalcone derivative lb. Antioxidant activity was also carried out to evaluate the antioxidant nature of the chalcone derivative lb by DPPH and H2O2 assay. (C) 2020 Elsevier B.V. All rights reserved.