Novel Ferrocenyl Chalcone Compounds as Possible Antimicrobial Agents

The increased prevalence of drug-resistant bacteria has quickly become a global concern as infections spread from healthcare settings to the wider community. The rapid spread of infections caused by bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) is partly facilitated by misuse and abuse of conventional drug therapies and a decreased development of new drugs.
Chalcones, which are a class of plant-based flavonoids, have become the focus of much research in medicinal chemistry since they inhibit bacterial growth. Ferrocenyl chalcones, which are chalcone derivatives, have gained further attention from researchers. In these compounds, ring A is replaced with a ferrocenyl moiety. Key characteristics of ferrocenyl chalcones include their small size, lipophilicity, an important feature allowing diffusion across cell membranes, ease of chemical modification and accessible one-electron-oxidation potential. Early classes of ferrocenyl chalcones were reportedly toxic to mammalian cells. This cytotoxicity to mammalian cells encouraged the need to develop next-generation ferrocenyl chalcone compounds that are less toxic.
Using 2-fold broth microdilution, results demonstrated that 5 of the 10 newly developed ferrocenyl chalcones possessed greater antimicrobial activity against Gram-positive organisms than Gram-negative organisms. These novel ferrocenyl chalcone compounds were active against three (3) types of drug-resistant S. aureus, including a MRSA, and other non-resistant Gram-positive bacteria. These compounds contain increasing alkyl chain lengths from 5-10 on ring B. The same compounds inhibited growth in non-resistant bacteria by obstructing cellular respiration in Gram-positive bacteria. The results indicate that these newly developed compounds could be important antimicrobial agents in the treatment of infections from clinically resistant bacteria.