Cationic and non-peptide small molecules containing a total of six positive charges arranged on one side and a long aliphatic tail on the other have been synthesized and tested against Gram-positive and Gram-negative bacteria. The positive charges have been contributed by two aminophenol residues. These molecules have showed remarkable antimicrobial activity against Gram-positive bacteria including multidrug-resistant strains. Our structure⁻activity relationship studies demonstrated the importance of the length and flexibility of the hydrophobic tail for the antimicrobial activity. Importantly, these compounds are non-toxic to eukaryotic cells at the concentration affecting growth in bacteria, reflecting an acceptable margin of safety. The small size and easy synthetic accessibility of our molecules can be of interest for the further development of novel antimicrobials against Gram-positive bacterial pathogens, including multidrug-resistant strains.
Keywords: antibiotic resistance; antimicrobial agents; antimicrobial peptides.