Design, Synthesis, and Antimicrobial Evaluation of Novel Quinolone Imidazoles and Interactions with MRSA DNA.

A novel series of quinolone imidazoles as new type of antimicrobial agents were synthesized. Most compounds exhibited good bioactivities especially against MRSA even superior to reference drugs. They induced bacterial resistance more slowly than clinical drugs and gave low cytotoxicity to human cells. The pKa values of these compounds showed appropriate ranges to pharmacokinetic behaviors. The interactions between compound 8b, Cu(2+) ion, and MRSA DNA revealed that compound 8b could intercalate into DNA through copper ion bridge to form a steady 8b-Cu(2+) -DNA ternary complex which might further block DNA replication to exert the powerful bioactivities. Study of compound 8b with human serum albumin indicated that compound 8b could be effectively stored and carried by human serum albumin.