BINDING OF NORFLOXACIN, ENOXACIN AND ENROFLOXACIN TO CALF THYMUS DNA

摘要

A number of drugs exert their influence by interaction with nucleic acids, having as effect the inhibition of replication and transcription. The precise mechanism by which these functions are inhibited is unique to each clinically important agent and may involve inhibition of DNA polymerase activity, topoisomerase II activity, etc. A fundamental step in understanding the molecular mechanism of drugs' action is the characterization of their binding to DNA and/or RNA. Fluoroquinolones are a class of antimicrobial antibiotics that destroy bacteria by inhibiting enzymes DNA gyrase and DNA topoisomerase. They are useful in the treatment of many infections, including urinary tract infections, respiratory infections, sexually transmitted diseases, acute bronchitis and sinusitis. In the present study, the interaction of three fluoroquinolones, norfloxacin, enoxacin and enrofloxacin, with calf thymus DNA has been studied. The study has been done by means of using various techniques such as UV-Vis absorption spectroscopy and viscosity measurements. The viscosity experiments have revealed how these drugs bind to DNA while the spectroscopic experiments have allowed the determination of the binding parameters. The results have been processed in terms of Benesi-Hildebrand, Scott and Scatchard models, assuming that binding of drugs to DNA is in 1:1 system and they also have been fitted through the linear or nonlinear regression, assuming that there is one single class of non-interacting binding sites that do not exhibit cooperative behaviour.