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

A series of β-chalcones derivatives (1a–1l) 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–1l) 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 (Kb) 1.75 × 104 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 1b. Antioxidant activity was also carried out to evaluate the antioxidant nature of the chalcone derivative 1b by DPPH and H2O2 assay. [Display omitted] •A series of new chalcone derivatives has been synthesized and characterized.•Antibacterial activity revealed that chalcone derivative 1b showed significant potential against tested bacterial strains.•The interaction ability with Ct-DNA showed that chalcone derivative 1b interacts with DNA by intercalative mode of binding.•DFT study was carried out to confirm the experimental data.•Antioxidant assay was also carried out to estimate the antioxidant potential of the chalcone derivative 1b.