Synthesis and Biological Evaluation of Piperazine Hybridized Coumarin Indolylcyanoenones with Antibacterial Potential.

A class of piperazine hybridized coumarin indolylcyanoenones was exploited as new structural antibacterial frameworks to combat intractable bacterial resistance. Bioactive assessment discovered that 4-chlorobenzyl derivative showed a prominent inhibition on ATCC 27853 with a low MIC of 1 μg/mL, which was four-fold more effective than norfloxacin. Importantly, the highly active with inconspicuous hemolysis towards human red blood cells displayed quite low proneness to trigger bacterial resistance. Preliminary explorations on its antibacterial behavior disclosed that possessed the ability to destroy bacterial cell membrane, leading to increased permeability of inner and outer membranes, the depolarization and fracture of membrane, and the effusion of intracellular components. Furthermore, bacterial oxidative stress and metabolic turbulence aroused by also accelerated bacterial apoptosis. In particular, could not only effectively inset into DNA, but also bind with DNA gyrase through forming supramolecular complex, thereby affecting the biological function of DNA. The above findings of new piperazine hybridized coumarin indolylcyanoenones provided an inspired possibility for the treatment of resistant bacterial infections.