Ferrocenyl chalcone derivatives as possible antimicrobial agents

The swift spread of infections caused by drug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), has quickly become a worldwide concern as infections spread from healthcare settings to the wider community. While ferrocenyl chalcones, which are chalcone derivatives with antimicrobial activity, have gained attention from researchers, further study is needed to assess their cytotoxicity. Ten newly developed chalcones, in which ring A was replaced with a ferrocenyl moiety and ring B contained increasing alkyl chain lengths from 1 to 10 carbons, were assessed. Using twofold broth microdilution, the minimum inhibitory concentration (MIC) of five of the ten compounds were lower against Gram-positive organisms (MICs from 0.008 mg ml−1 to 0.063 mg ml−1) than Gram-negative organisms (MICs = 0.125 mg ml−1). These novel ferrocenyl chalcone compounds were effective against three types of clinically isolated drug-resistant S. aureus, including an MRSA, and against other non-resistant clinically isolated and laboratory-adapted Gram-positive bacteria. The same compounds inhibited growth in non-resistant bacteria by potentially obstructing cellular respiration in Gram-positive bacteria. Images obtained through scanning electron microscopy revealed fully lysed bacterial cells once exposed to a selected compound that showed activity. The results indicate that these newly developed compounds could be important antimicrobial agents in the treatment of infections from clinically resistant bacteria.