Synthesis and antibacterial activity of environmentally friendly sulfonium compounds

Abstract

The abuse and overuse of antibacterial drugs have caused the increasing drug resistance of pathogenic bacteria, which threats human health and environmental health. Therefore the development of new environmentally friendly antibacterial drugs is of great urgency. The purpose of this study is to develop novel sulfonium compounds and evaluate their antibacterial activities. The sulfonium compounds were obtained by substitution reactions of methionine. The antimicrobial activities of the compounds were evaluated by measurement of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against S. aureus and E. coli. A total of fifteen sulfonium compounds were synthesized and all of them showed antibacterial activity that varied with the substitution chain length. These compounds were highly sensitive to S. aureus with the lowest MIC and MBC at 0.39 μmol/L and 1.56 μmol/L, respectively, which are lower than that of commercial quaternary ammonium compounds. An extra group of eight sulfonium compounds were also constructed to study the relationship between compound structures and their antibacterial abilities. A preferred structure with one longer hydrophobic alkyl chain at the amine position has been demonstrated for better antibacterial activity.

Methionine based sulfonium compound as environmentally friendly antibacterial agent.