Synthesis and antibacterial and cytotoxic activities of new N-3 substituted thiazolidine-2,4-dione derivatives bearing the pyrazole moiety.

Two new series of N-3 substituted thiazolidine-2,4-dione derivatives bearing the pyrazole moiety (5a-j and 7a-j) were synthesized and assessed in vitro for their efficacy as antibacterial agents against gram-positive and gram-negative bacterial strains. Among the tested compounds, 7b, 7c, 7i, and 7j were found to be active against gram-positive bacteria (Staphylococcus aureus and Streptococcus pyogenes) with minimum inhibitory concentration (MIC) values in the range of 6.25-25 µg/mL, and some compounds were also tested against methicillin-resistant S. aureus (MRSA). Compounds 7c and 7j inhibited the growth of MRSA at MIC values of 6.25 and 12.5 µg/mL, respectively. The influence of the lipophilicity (C log P) on the biological profile (MIC) of the prepared products was also discussed. From the standpoint of structure-activity relationship studies, it was observed that the lipophilic profiles of the compounds were crucial for their antibacterial activities. Further, the results of the MTT cytotoxicity studies on a human cervical cancer cell line (HeLa) and a mouse embryonic fibroblast cell line (NIH 3T3) suggested that compounds 7b, 7c, 7i, and 7j were endowed with low levels of cytotoxicity.