Molecular Characterisation and Antimicrobial Activities of Novel Substituted Ferrocenyl Chalcone Derivatives

The increasing issues of drug-resistant bacteria has quickly become a global concern as infections spread from healthcare settings to the wider community. The rapid spread of these infections is partly facilitated by a decrease in the development of new drugs.
Because of their antimicrobial properties, ferrocenyl chalcones, which are organometallic chalcone derivatives, have gained attention from researchers. Early classes of ferrocenyl chalcones were reportedly cytotoxic, which encouraged the need to develop next-generation ferrocenyl chalcone compounds that are less toxic.
One-to-one dilutions of stock ferrocenyl chalcone solution and MHB, resulting in the formation of small, brown particles, was suggested to arise from iron ion chelation of casein hydrolysate, a component of MHB. After solubilisation in DMSO, each of the iodine-containing ferrocenyl chalcone compounds, changed from deep red to dark brown. There was no evidence that iodine was displaced when diethyl ether was used.
Using 2-fold broth microdilution, results demonstrated that five of the ten methylated ferrocenyl chalcones, possessed greater antimicrobial activity against resistant and non-resistant Gram-positive organisms than Gram-negative organisms. These compounds contain increasing alkyl chain lengths from pentyl to decyl on ring ‘B’ of the compounds.
The results of MTT assays of Gram-positive bacteria indicated that there were no viable cells, where the mean (± SD) percentage of actively respiring cells were observed.
SEM images of bacterial cells, which were treated with an active ferrocenyl chalcone, exhibited significant cell membrane damage as ultrastructurally observed.
Key findings of this research indicate that further investigations into these compounds are required so that the inhibition of biofilm formation and the cytotoxicity towards mammalian cells are clearly defined. Additionally, the results advance the possibility that these newly developed ferrocenyl chalcone compounds could be important antimicrobial agents in the treatment of infections from clinically resistant bacteria in an environment where current treatments are failing.