Synthesis, crystal structure, DFT calculations, in-vitro and in-silico studies of novel chromone-isoxazoline conjugates as antibacterial and anti-inflammatory agents.

In this study, we report the synthesis and biological evaluation of a novel series of chromone-isoxazoline hybrids. These conjugates were successfully synthesized through N-alkylation and 1,3-dipolar cycloaddition reactions, and their structures were determined by spectroscopic analysis (1H and 13C-NMR), mass spectrometry (MS), and X-ray diffraction (XRD) analysis. The XRD study showed that the compound crystallizes in the monoclinic system (S.G: P21/c). The antibacterial activity of the hybrid compounds was assessed in vitro against the Gram-positive bacterium Bacillus subtilis ATCC 6633 and three Gram-negative bacteria (Klebsiella aerogenes ATCC 13,048, Escherichia coli ATCC 27,853, and Salmonella enterica serotype Typhi) using the disk diffusion technique, MIC and MBC assays. The results showed that some tested compounds exhibited promising efficacy compared to the standard antibiotic chloramphenicol, underscoring their potential as antibacterial agents. These results were further validated through the determination of MIC and MBC values using the microdilution test, which showed a strong bactericidal effect of some compounds against the selected bacterial strains. Additionally, the studied compounds showed good anti-inflammatory potential by effectively inhibiting 5-LOX enzyme, with compound 5e was the most active, presenting an IC50 value of 0.951 ± 0.02 mg/mL. These in vitro results were complemented by in silico studies, including ADMET (absorption, distribution, metabolism, excretion, and toxicity) predictions and molecular docking simulations. The docking analyses provided insights into the inhibition mechanisms, revealing specific interactions of the synthesized molecules with target proteins relevant to both their antibacterial and anti-inflammatory activities. Finally, density functional theory (DFT)-based calculations were performed to optimize the geometric structures and analyze the structural and electronic properties of the hybrid compounds. While the results are promising, further optimization of compound potency is necessary to enhance their therapeutic potential.