Design of Arylsulfonylhydrazones as Potential FabH Inhibitors: Synthesis, Antimicrobial Evaluation and Molecular Docking

Abstract

Background: Antimicrobial resistance is a persistent problem regarding infection treatment and calls for developing new antimicrobial agents. Inhibition of bacterial β-ketoacyl acyl carrier protein synthase III (FabH), which catalyzes the condensation reaction between a CoAattached acetyl group and an ACP-attached malonyl group in bacteria is an interesting strategy to find new antibacterial agents.

Objective: The aim of this work was to design and synthesize arylsulfonylhydrazones potentially FabH inhibitors and evaluate their antimicrobial activity.

Methods: MIC₅₀ values of sulfonylhydrazones against E. coli and S. aureus were determined. Antioxidant activity was evaluated by DPPH (1-1'-diphenyl-2-picrylhydrazyl) assay and cytotoxicity against LL24 lung fibroblast cells was verified by MTT method. Principal component analysis (PCA) was performed in order to suggest a structure-activity relationship. Molecular docking allowed to propose sulfonylhydrazones interactions with FabH.

Results: The most active compound showed activity against S. aureus and E. coli, with MIC₅₀ = 0.21 and 0.44 μM, respectively. PCA studies correlated better activity to lipophilicity and molecular docking indicated that sulfonylhydrazone moiety is important to hydrogen-bond with FabH while methylcatechol ring performs π-π stacking interaction. The DPPH assay revealed that some sulfonylhydrazones derived from the methylcatechol series had antioxidant activity. None of the evaluated compounds was cytotoxic to human lung fibroblast cells, suggesting that the compounds might be considered safe at the tested concentration.

Conclusion: Arylsufonylhydrazones is a promising scaffold to be explored for the design of new antimicrobial agents.

Keywords: FabH inhibitors; Sulfonylhydrazone; antibacterial; antioxidant; methylcatechol; molecular docking..