Evaluation of 1-vinyl-3-alkyl imidazolium-based ionic liquid monomers towards antibacterial activity: An in-silico & in-vitro study

Abstract

In this study 1-vinyl-3-alkyl imidazolium-based ionic liquid monomers (ILs) with different alkyl chain lengths {R = hexyl (A), octyl (B) and decyl (C)} have been synthesized for antibacterial applications. The prepared ILs have been characterized using UV, FT-IR and NMR spectroscopy. The antibacterial activities of the synthesized ILs against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) have been examined by measuring their minimal inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). The results exhibit that these ILs have admirable antibacterial activities with MIC values range from < 1.2 to 12.2 μM for S. aureus and < 2.4 to 12.2 μM for E. coli. A notable dependence of antibacterial and antibiofilm efficacy on the alkyl chain length (ILC> ILB > ILA) has been observed. From in-silico evaluation, the binding energies of β-lactamase protein of S. aureus (PDB ID: 1GHP) are found to be −4.4, −4.6, −4.7 kcal/mol for IL A, IL B, and IL C. For dihydrofolate reductase (DHFR) of S. aureus and E. coli the binding energies −4.6, −4.5, −5.3 kcal/mol and −5.3, −5.4, −5.6 kcal/mol have been noted for IL A, IL B, and IL C respectively. MD simulations (100 ns) have been performed to predict the stability and understand the binding mechanism of the docked complexes.