Background: An alarming increment in pathogenic resistance to existing
anti-microbial agents is a serious problem and the treatment of these bacterial
infections is becoming increasingly challenging. Therefore, there is an urgent need
to develop novel antimicrobial agents.
Objective: As a part of our ongoing studies toward the development of novel antibacterial
agents, the synthesis and antibacterial activity of a series of (Z)-5-((3-phenyl-1H-pyrazol-4-yl)methylene)-2-thioxothiazolidin-4-one derivatives will be
discussed in this study.
derivatives were designed, synthesized and evaluated for antibacterial activity. The structures were
confirmed by IR, 1H NMR, 13C NMR and mass spectrometry. All of the synthesized compounds
were evaluated in vitro using a 96-well microtiter plate and a serial dilution method to obtain their
minimum inhibitory concentration (MIC) values against a variety of different strains, including
multidrug-resistant clinical isolates.
Results: The antibacterial test in-vitro showed that most compounds in series 7 and 9 exhibited significant
inhibitory activities against anaerobic bacteria (Streptococcus mutans) strains with a MIC
value of 1 µg/mL. Compounds 7c and 9c showed the most potent activity against MRSA (3167 and
3506) with a minimum inhibitory concentration (MIC) value of 1 µg/mL, which is equivalent to
moxifloxacin and greater than gatifloxacin, oxacillin and norfloxacin. Additionally, compound 9c
showed potent antibacterial activity against Bacillus subtilis (aerobic bacteria) with a MIC value of 2 µg/mL.
Conclusion: The work suggests that these type of rhodanine compounds had a better potent activity
against MRSA compared with other perviously reported rhodanine derivatives, which might provide
a valuable information for the development of new antibacterial agents against multidrug-resistant
clinical isolates MRSA.