Pradhuman A. Parmar

Square pyramidal copper(II) complexes with forth generation fluoroquinolone and neutral bidentate ligand: structure, antibacterial, SOD mimic and DNA-interaction studies.

Coordination of neutral bidentate ligand to copper ion in combination with gatifloxacin have been focused in this article. The effect of complexation reflects antibacterial activity, DNA interaction and SOD mimic activity of individual greatly. The geometry at the central metal ion provides a site for binding of superoxide anion responsible for better SOD mimic behaviour.

Antibacterial and DNA interaction studies of zinc(II) complexes with quinolone family member, ciprofloxacin

DNA binding and cleavage characteristics of Zn(II) complexes have been investigated. The DNA interaction property of the complexes has been investigated using absorption spectra, viscosity measurements, as well as gel electrophoresis studies. Intrinsic binding constant (K(b)) has been estimated under similar set of experimental conditions. Absorption spectral study indicate that the Zn(II) complexes intercalate between the base pairs of the DNA tightly with intrinsic binding constant in the range of 1.0 x 10(4)-4.0 x 10(4)M(-1) in phosphate buffer. The proposed DNA binding mode supports the large enhancement in the relative viscosity of DNA on binding. The antimicrobial activity of all the ligands and metal complexes has been examined by minimum inhibitory concentration method (MIC).

Five-coordinated oxovanadium(IV) complexes derived from amino acids and ciprofloxacin: synthesis, spectral, antimicrobial, and DNA interaction approach.

Five-coordinated oxovanadium(IV) complexes with ciprofloxacin and various uninegative bidentate amino acids have been prepared. The structure of complexes has been investigated using spectral, physicochemical, mass spectroscopy, and elemental analyses. The antimicrobial activities (MIC) of the complexes, ligands, metal salt, and some standard drugs have been evaluated using the doubling dilution technique against Staphylococcus aureus, Bacillus subtilis, Serratia marcescens (gram-positive), and Pseudomonas aeruginosa, and Escherichia coli (gram-negative) bacteria. The result shows the significant increase in the antibacterial activity of the ligand, metal, and ciprofloxacin on complexation. The interaction of the complexes with pBR322 DNA has been investigated using spectroscopic, gel electrophoresis, and viscometric techniques. This shows that the complexes can bind to pBR322 DNA by the intercalative mode. The superoxide dismutase-like activity of the complexes has been determined.

Effect of substituent of terpyridines on the DNA-interaction of polypyridyl ruthenium(II) complexes

An octahedral complexes of ruthenium with 2,9-dimethyl-1,10-phenanthroline (dmphen) and substituted terpyridine have been synthesized. The Ru(II) complexes have been characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, FT-IR, electronic, (1)H NMR and FAB mass spectra. The binding strength and mode of interaction of the complexes with Herring Sperm DNA has been investigated using absorption titration and viscosity measurement studies. Results suggest that the substituent on terpyridine ligand affects the binding mode and binding ability of the complexes. Effect of time and ionic strength on DNA cleavage ability of complex has also been studied by gel electrophoresis. Results suggest that more than 200 mM concentration of NaCl decreases the cleavage ability of complex.

Antibacterial, nuclease, and SOD-mimic behaviors of copper(II) complexes of norfloxacin and phenanthrolines

Square-pyramidal complexes [Cu(NFL)(A n )Cl] · 5H2O (A n  = phenanthroline derivatives and NFL = deprotonated norfloxacin) have been synthesized and characterized. Interactions with Herring Sperm DNA and pUC19 DNA have been investigated. Mode and extent of interaction was measured by the perturbation in absorbance of complexes in the absence and presence of DNA. Hydrodynamic volume change and gel electrophoretic results were also kept under consideration. Synthesized complexes bind to DNA via intercalation with binding constant 0.875–1.446 × 104 (mol L−1)−1 based on bathochromism and hypochromism observed. Intercalative binding of complexes with DNA was further supported by relative viscosity, where 5 intercalates more strongly with most increase in relative viscosity, and K b value of 1.446 × 104 (mol L−1)−1. Evaluation of electrophoretic separation of plasmid on agarose gel reveals that 5 cleaves more efficiently. Square-pyramidal geometry at the metal center supports superoxide-dismutase (SOD)-mimic behavior in addition to an electron-withdrawing group on the ancillary ligand stabilizing Cu–O bonding.

DNA-binding and cleavage activity of polypyridyl ruthenium(II) complexes

Polypyridyl ruthenium(II) complexes [RuII(3-bptpy)(dmphen)Cl]ClO4 (1), [RuII(3-cptpy)(dmphen)Cl]ClO4 (2), [RuII(2-tptpy)(dmphen)Cl]ClO4 (3), and [RuII(9-atpy)(dmphen)Cl]ClO4 (4) {where 3-bptpy = 4′-(3-bromophenyl)-2,2′:6′,2″-terpyridine, 3-cptpy = 4′-(3-chlorophenyl)-2,2′:6′,2″-terpyridine, 2-tptpy = 4′-(2-thiophenyl)-2,2′:6′,2″-terpyridine, 9-atpy = 4′-(9-anthryl)-2,2′:6′,2″-terpyridine, dmphen = 2,9-dimethyl-1,10-phenanthroline} have been synthesized and characterized. The DNA-binding properties of the complexes with Herring Sperm DNA have been investigated by absorption titration and viscosity measurements. The ability of complexes to break the pUC19 DNA has been checked by gel electrophoresis. The experimental results suggest that all the complexes bind DNA via partial intercalation. The results also show that the order of DNA-binding affinities of the complexes is 4 < 3 < 2 < 1, confirming that planarity of the ligand in a complex is very important for DNA-binding.

Third generation fluoroquinolones antibacterial drug based mixed-ligand Cu(II) complexes: structure, antibacterial activity, superoxide dismutase activity and DNA–interaction approach

The copper(II) complexes of the type [Cu(SPF)(An)Cl]/[Cu(PFL)(An)Cl] (where SPF is sparfloxacin, PFL is pefloxacin and An is 2,2′-dipyridylamine/pyridine-2-carboxalehyde/thiophene-2-carboxaldehyde) were synthesised and were found to have a pyramidal geometry with a square base. The superoxide dismutase (SOD) like activity of the complexes were measured using an NBT/NADH/PMS system, these were expressed in terms of the concentration of complex which termianates the formation of formazan by 50% (IC50 value) and found to range from 0.781 to 1.354 μM. The interactions of the complexes with DNA were studied by absorption titration, viscosity measurement and gel electrophoresis under physiological conditions. The antimicrobial efficiency of the complexes were tested on five different microorganisms and showed good biological activity.

Synthesis, characterization, and thermal and biocidal aspects of drug-based metal complexes

Drug-based metal complexes [M(L)(A)(H2O)2] (M = Cu(II), Ni(II), Co(II), Zn(II), Cd(II), Mn(II), A = atenolol and L = ciprofloxacin) have been prepared and characterized using infrared spectra, electronic spectra, magnetic measurements, elemental analyses, and thermal investigation. Spectral investigations of metal complexes assume monomeric six-coordinate octahedral geometry. All the synthesized complexes exhibit higher biocidal activity against Bacillus subtilis, Escherichia coli, Bacillus cereus, Staphylococcus aureus, Salmonella typhi, and Serratia marcescens compared to parent compounds and standard drugs.

Ternary copper(II) complexes of levofloxacin and phenanthroline derivatives: In-vitro antibacterial, DNA interactions, and SOD-like activity

A series of ternary copper(II) complexes have been derived using levofloxacin and five phenanthroline derivatives. Complexes were characterized using infrared spectroscopy, Thermogravimetric (TG)-analysis, fast atom bombardment mass spectroscopy and reflectance spectra. Synthesized complexes exhibit the only d-d band at ∼ 666 nm points toward a distorted square pyramidal geometry at metal centre with one unpaired electron responsible for paramagnetic behaviour of whole moiety. Binding behaviour of the complexes toward Herring Sperm DNA were determined using ultraviolet-Vis (UV-Vis) absorption titration and viscometric titration experiment, where as the cleavage efficacy of the complexes toward pUC19 DNA was determined by electrophoresis in presence of ethidium bromide. Complexes exhibit superoxide dismutase–like activity with their IC50 values ranging from 0.7917 to 1.7432 µM.

Spectrophotometric determination of ciprofloxacin by ion pair formation

Various aspects of application of derivative spectrophotometry to chemical analysis and investigations of equilibria and kinetics of reactions are scrutinised. In this work the viability of a spectrophotometric technique for the determination of ciprofloxacin has been deliberated. The method is based on the formation of ion-association complexes of ciprofloxacin with nickel(II) tetra thiocyanate, which are extracted into organic solvent (40% n-butanol in methylene chloride) having absorption maxima at 623 nm. The precision and accuracy of the method was checked by UV reference methods. The validation study indicated the parameters, which are in good agreement with the data obtained from standard methods. The proposed method was fruitfully applied to determine ciprofloxacin in their tablet formulations.