Synthesis Of Norfloxacin Metal Complexes And Bioactivity Study

The carboxyl group and carbonyl group in Norfloxacin can bind with metal ions.In this paper,some biological metal ions,such as Cu(â…¡),Mn(â…¡),Zn(â…¡), Ni(â…¡),Co(â…¡),Mg(â…¡),were selected to synthesize norfloxacin-metal complexes. Their biological activities were studied.1.A series of norfloxacin-metal complexes were synthesized.Many techniques were used to analysis the structural properties such as infrared absorption spectroscopy,differential thermal analysis,conductivity measurements,etc.In order to introduce N-N ligand,Phenanthroline was added to obtain different metal-norfloxacin-Phen ternary complexes.2.The action of metal-norfloxacin,metal-norfloxacin-Phenanthroline compounds on Escherichia coli was studied by microcalorimetry.According to thermokinetic equationln p_t=ln p0+kt,the rate constant k,the time of generations of bacterium T_G and the half-inhibitory concentration Ic₅₀ were calculated.By the values of rate constant k and half-inhibitory concentration Ic₅₀,the biological activity of metal complexes were estimated quantitatively.The smaller the Ic₅₀ was,the greater the antibacterial action of metal complexes was.The results showed that, both the binary complexes and ternary complexes have the antibacterial activity.At high concentrations of complexes,Escherichia's growth can be inhibited completely, showing strong antibacterial activities.3.The toxicity of metal complexes on Tetrahymena thermopHila was studied by microcalorimetry.The rate constant k,the time of generations of bacterium T_G and the half-inhibitory concentration Ic₅₀ were calculated from the growth curves. These thermal kinetic parameters were used to compare the different actions of metal complexes on Tetrahymena thermopHila.The results showed that,some metal complexes can stimulus the growth of Tetrahymena thermopHila at low concentration,but at high concentration,they can inhibit the growth of tetrahymena thermopHila.4.UV spectrometer was used to study the interactions of metal complexes with DNA.The binding constants of metal complexes with DNA were calculated and the interaction mode was discussed.It was found that,as the DNA concentration increases,hypo chromic effect in UV spectrometer can be observed,but the red-shift in not obvious,which indicates that norfloxacin-metal complexes partly inserted into DNA.