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Dimiza F.,Aristotle University of Thessaloniki | Papadopoulos A.N.,Alexandrion Technological Educational Institution | Tangoulis V.,Aristotle University of Thessaloniki | Psycharis V.,Greek National Center For Scientific Research | And 3 more authors.
Journal of Inorganic Biochemistry | Year: 2012

Cobalt(II) complexes with the non-steroidal anti-inflammatory drug naproxen in the presence or absence of nitrogen-donor heterocyclic ligands (pyridine, 2,2′-bipyridine or 1,10-phenanthroline) have been synthesized and characterized with physicochemical and spectroscopic techniques. The deprotonated naproxen acts as monodentate ligand coordinated to Co(II) ion through a carboxylato oxygen. The crystal structure of [bis(aqua) bis(naproxenato)bis(pyridine)cobalt(II)], 2 has been determined by X-ray crystallography. The EPR spectrum of complex 2 in frozen solution reveals that it retains its structure. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that the complexes can bind to CT DNA and [(2,2′-bipyridine)bis(methanol)bis(naproxenato)cobalt(II)] exhibits the highest binding constant to CT DNA. The cyclic voltammograms of the complexes recorded in DMSO solution and in the presence of CT DNA in 1/2 DMSO/buffer (containing 150 mM NaCl and 15 mM trisodium citrate at pH 7.0) solution have shown that they can bind to CT DNA by the intercalative binding mode which has also been verified by DNA solution viscosity measurements. Competitive study with ethidium bromide (EB) has shown that the complexes can displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB. Naproxen and its cobalt(II) complexes exhibit good binding propensity to human or bovine serum albumin proteins having relatively high binding constant values. The antioxidant activity of the compounds has been evaluated indicating their high scavenging activity against hydroxyl free radicals and superoxide radicals. © 2011 Elsevier Inc. All rights reserved. Source


Zampakou M.,Aristotle University of Thessaloniki | Rizeq N.,Aristotle University of Thessaloniki | Tangoulis V.,Aristotle University of Thessaloniki | Papadopoulos A.N.,Alexandrion Technological Educational Institution | And 3 more authors.
Inorganic Chemistry | Year: 2014

Manganese(II) complexes with the non-steroidal anti-inflammatory drug tolfenamic acid (Htolf) with the nitrogen-donor heterocyclic ligands 1,10-phenanthroline (phen), pyridine (py), or 2,2′-bipyridylamine (bipyam) and/or the oxygen-donor ligands H2O or N,N-dimethylformamide (DMF) have been synthesized and characterized. The crystal structures of complexes [Mn(tolf-O)(tolf-O,O′)(phen)(H2O)], [Mn2(μ 2-tolf-O,O′)2(tolf-O,O′)2(bipyam) 2], [Mn2(μ2-H2O) (μ2-tolf-O,O′)2(tolf-O)2(py) 4]·1.5MeOH·py, and [Mn(μ2-tolf-O, O′)2(DMF)2]n have been determined by X-ray crystallography. The interaction of the complexes with serum albumin proteins was investigated, and relative high binding constant values were calculated. The ability of the compounds to scavenge 1,1-diphenyl- picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), and hydroxyl radicals was evaluated, and [Mn(tolf)2(phen)(H 2O)] was the most active scavenger among the compounds. The compounds have also exhibited noteworthy in vitro inhibitory activity against soybean lipoxygenase. UV titration studies of the interaction of the complexes with calf-thymus (CT) DNA have proved the binding to CT DNA with [Mn(μ 2-tolf)2(DMF)2]n exhibiting the highest DNA-binding constant (Kb = 5.21 (±0.35) × 105 M-1). The complexes bind to CT DNA probably via intercalation as suggested by DNA-viscosity measurements and competitive studies with ethidium bromide (EB), which revealed the ability of the complexes to displace the DNA-bound EB. © 2014 American Chemical Society. Source


Zampakou M.,Aristotle University of Thessaloniki | Hatzidimitriou A.G.,Aristotle University of Thessaloniki | Papadopoulos A.N.,Alexandrion Technological Educational Institution | Psomas G.,Aristotle University of Thessaloniki
Journal of Coordination Chemistry | Year: 2015

The interaction of MnCl2 with the non-steroidal anti-inflammatory drug sodium diclofenac in the presence of 2,2′-bipyridine and pyridine resulted in the formation of cationic and neutral mononuclear complexes [Mn(diclofenac)(2,2′-bipyridine)(H2O)2] (diclofenac) (1) and [Mn(diclofenac)2(pyridine)2(H2O)2] (2), respectively. The structure of 1 was characterized by X-ray crystallography. In a preliminary attempt to evaluate the biological properties and possible application, the interaction of the complexes with calf-thymus DNA and human or bovine serum albumins was monitored. Additionally, the ability of the compounds to scavenge radicals such as 1,1-diphenyl-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and hydroxyl radicals was evaluated; the complexes were more potent scavengers than free sodium diclofenac. © 2015 Taylor & Francis. Source


Skyrianou K.C.,Aristotle University of Thessaloniki | Perdih F.,University of Ljubljana | Papadopoulos A.N.,Alexandrion Technological Educational Institution | Turel I.,University of Ljubljana | And 2 more authors.
Journal of Inorganic Biochemistry | Year: 2011

The nickel(II) complexes with the quinolone antibacterial agents oxolinic acid, flumequine, enrofloxacin and sparfloxacin in the presence of the N,N′-donor heterocyclic ligand 2,2′-bipyridylamine have been synthesized and characterized. The quinolones act as bidentate ligands coordinated to Ni(II) ion through the pyridone oxygen and a carboxylato oxygen. The crystal structure of [(2,2′-bipyridylamine)bis(sparfloxacinato) nickel(II)] has been determined by X-ray crystallography. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that they bind to CT DNA with [(2,2′-bipyridylamine)bis(flumequinato)nickel(II)] exhibiting the highest binding constant to CT DNA. The cyclic voltammograms of the complexes have shown that in the presence of CT DNA the complexes can bind to CT DNA by the intercalative binding mode which has also been verified by DNA solution viscosity measurements. Competitive study with ethidium bromide (EB) has shown that the complexes can displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB. The complexes exhibit good binding propensity to human or bovine serum albumin protein having relatively high binding constant values. The biological properties of the [Ni(quinolonato) 2(2,2′-bipyridylamine)] complexes have been evaluated in comparison to the previously reported Ni(II) quinolone complexes [Ni(quinolonato) 2(H 2O) 2], [Ni(quinolonato) 2(2,2′-bipyridine)] and [Ni(quinolonato) 2(1,10- phenanthroline)]. The quinolones and their Ni(II) complexes have been tested for their antioxidant and free radical scavenging activity. They have been also tested in vitro for their inhibitory activity against soybean lipoxygenase. © 2011 Elsevier Inc. All rights reserved. Source


Totta X.,Aristotle University of Thessaloniki | Papadopoulou A.A.,Aristotle University of Thessaloniki | Hatzidimitriou A.G.,Aristotle University of Thessaloniki | Papadopoulos A.,Alexandrion Technological Educational Institution | Psomas G.,Aristotle University of Thessaloniki
Journal of Inorganic Biochemistry | Year: 2015

Six novel nickel(II) complexes with the non-steroidal anti-inflammatory drug mefenamic acid (Hmef) with the nitrogen-donor heterocyclic ligands 2,2′-bipyridine (bipy), 2,2′-bipyridylamine (bipyam), 1,10-phenanthroline (phen), 2,2′-dipyridylketone oxime (Hpko) or pyridine (py) and/or the oxygen-donor ligands CH3OH or H2O were synthesized and characterized by physicochemical and spectroscopic techniques. The crystal structures of [Ni(mef-O)2(bipy)(CH3OH)2] (1), [Ni(mef-O)2(phen)(CH3OH)2] (2), [Ni(mef-O,O′)2(bipyam)] (3) and [Ni(mef-O)2(Hpko)2]CH3OH (4·CH3OH) were determined by X-ray crystallography. The ability of the complexes to scavenge 1,1-diphenyl-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and hydroxyl radicals was investigated and the in vitro inhibitory activity against soybean lipoxygenase was evaluated; complexes 3 and 4 were the most active compounds. Spectroscopic (UV and fluorescence), electrochemical (cyclic voltammetry) and physicochemical (viscosity measurements) techniques were employed in order to study the binding mode of the complexes to calf-thymus (CT) DNA and to calculate the corresponding binding constants; for all complexes, intercalation was the most possible mode of DNA-binding. The interaction of the complexes with serum albumins was studied by fluorescence emission spectroscopy and the values of the albumin-binding constants were determined. © 2015 Elsevier Inc. Source

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