Novel benzyl phenyl sulfide derivatives as antibacterial agents against methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a major threat to human health due to its resistance to almost all classes of antibiotics. Discovery of novel antibacterial agents with new structures which combat the pathogens responsible for MRSA is urgent. In this study, three series of benzyl phenyl sulfide derivatives were designed and synthesized, and their antibacterial activity against eleven MRSA strains were evaluated. The results showed that two series of the synthetic compounds (5a-5l and 12p-12u) exhibit potent antibacterial activity against S. aureus and MRSA, with minimum inhibitory concentrations of 2-64 μg/mL. The structure-activity relationships are discussed and the mechanism of the antibacterial activity was shown to involve the destruction of the bacterial cell membrane. Finally, the MTT assay results suggest that the toxicity of compounds 5f and 5h is selective between bacteria and mammalian cells.