Design, synthesis, and biological evaluation of novel carbazole aminothiazoles as potential DNA-targeting antimicrobial agents

A series of novel carbazole aminothiazoles as a new type of antimicrobial agents were designed, synthesized and characterized by 1 H NMR, 13 C NMR, IR, MS and HRMS spectra. Some of the carbazole aminothiazoles exhibited good antimicrobial activities; particularly, heptyl-derived carbazole aminothiazole 4f could effectively inhibit the growth of MRSA with an MIC value of 4 μg mL −1 , which was superior to the reference drugs Chloromycin and Norfloxacin. Moreover, cytotoxicity investigation indicated that bioactive compound 4f did not exhibit cytotoxicity to Hep-2 cells within its MIC against MRSA. Preliminary interactive investigation revealed that compound 4f could effectively intercalate into calf thymus DNA to form 4f –DNA complexes which might block DNA replication and thus exert antimicrobial activities. In addition, the binding behavior of compound 4f to DNA revealed that compound 4f could interact with DNA by hydrogen bonds and electrostatic interactions.