Electrochemical Behaviors Of Fluoroquinolone Antibacterial Drug And Its Interaction With DNA

DNA is an important bio-macromolecule in life; it has especial biological function and has been playing many vital roles for all kinds of biological phenomena. Exploring the interaction mechamisms on these bio-macromolecules with small molecules, especially for those targeting-drug molecules at the molecule level is of current interested in many research areas such as biology, clinical medicine, medicinal chemistry, chemistry and so on. Quinolone drug is a kind of antibacterial drugs which have been usded widely in clinical medicine, but its pharmacology and toxicology still have to be studied further. This paper studied the interaction mechamisms among quinolone drug and DNA, and it was consisted of three parts.In the first part, calf thymus DNA (ctDNA) and lomefloxacin (LMF) have been selected for investigative object, and mechanism of LMF to ctDNA have been investigated by electrochemistry, fluorescence, UV/Vis absorbance spectra and gel electrophoresis. The interaction of LMF and ctDNA could result in a considerable decrease in the peak currents and positive shift in the peak potential, as well as quenching of fluorescence, red shift and isobestic point of UV/Vis adsorption spectra and the changes of electrophoresis speeds and luminance of gel electrophoresis. All the acquired data showed that an intercalation system occurred between LMF and ctDNA.In the second part, the interaction between ciprofloxacin (CFX) and ctDNA have been investigated, and the eletrooxidation mechanism of fluoroquinolone drugs. These acquired data of electrochemistry and spectra showed that the binding mode of CFX and ctDNA was mainly an intercalation mechanism. We also investigated other fluoroquinolone antibacterial agents, such as ofloxacin (OFX), sparfloxacin (SPX) and LMF, and thought the electrooxidation of fluoroquinolone drugs occurred on the nitrogen of piperazine moiety, distal to the molecule, furthermore the solution pH effected the electrooxidation. In the third part, we studied the interaction of Aciclovir (ACV) and single stranded DNA (ssDNA) and the binding constant. These acquired data of electrochemistry and spectra showed that the binding mode of ACV and ssDNA was mainly a hydrogen bonding mechanism, and the binding constant was 1.