Choline‐Based Ionic Liquids: Improvement of Antimicrobial Activity

Antibiotic resistance is a global public health concern. The choline-based ionic liquids (ILs) have raised particular attention in the design of “greener” ILs and can exert a broad-spectrum of antimicrobial activity. To improve antimicrobial chemotherapy, we herein tested the antimicrobial activity and toxicity of a wide range of choline-based ILs. Two series of compounds were synthesized -dimethylethanolamine monoquaternary ammonium salts (Series A) and -methyl diethanolamine, diethanolamine and triethanolamine monoquaternary ammonium salts (Series B). The antimicrobial screening revealed that compounds N-(2-hydroxyethyl)-N,N-dimethyl-1-tetradecanaminium bromide ([N1,1,14,2(OH)]Br), N-(2-hydroxyethyl)-N,N-dimethyl-1-hexadecanaminium bromide ([N1,1,16,2(OH)]Br) and N-(2-hydroxyethyl)-N,N-dimethyl-1-octadecanaminium bromide ([N1,1,18,2(OH)]Br) are potent antimicrobial agents. The presence of a hydroxyethyl group and as mention previously in the literature, the C14 to C16 linker in a choline compound improves the antimicrobial activity and lowers the cytotoxic properties of this class of compounds.