Objective: The aim of this study was to evaluate the influence of pharmacophores having naphthylamine and nitro groups on the antimicrobial (antibacterial and antifungal) activity of thiazolidinone derivatives.
Materials and methods: The initial 5-substituted-2-methylmercaptothiazolidin-4-ones were subjected to S-demethylation to yield 2-amino-substituted thiazolidinones. 4-Nitro-1-naphthylamine, nitrofuran aldehydes, and nitrobenzene aldehydes were used as pharmacophoric compounds having amino or aldehyde groups. Antimicrobial (antibacterial and antifungal) activity of the new compounds was tested in vitro against bacterial cultures - Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae - and fungal cultures - Candida albicans, Candida glabrata, Candida krusei, Candida kefyr, Candida tropicalis, and Candida parapsilosis.
Results: Microbiological analysis showed that all new thiazolidinone derivatives with nitronaphthylamine substituent possessed antibacterial and antifungal properties. New compounds 2a-b showed similar antibacterial activity in vitro against S. aureus and B. subtilis as aminopenicillins. The lowest antibacterial activity of all newly synthesized compounds was against capsule-forming bacteria K. pneumoniae and against gram-negative bacteria E. coli (minimum inhibitory concentration range, 500-1000 μg/mL).
Conclusions: The minimum inhibitory concentration of naphthylamine derivatives varied in the range of 0.4-1000 μg/mL, and activity of some newly synthesized compounds was similar to the activity of aminopenicillins and fluconazole, an antifungal preparation. Based on the results, it is possible to separate the perspective group of potential antimicrobial compounds.