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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.


Tarushi A.,Aristotle University of Thessaloniki | Karaflou Z.,Aristotle University of Thessaloniki | Kljun J.,University of Ljubljana | Turel I.,University of Ljubljana | And 3 more authors.
Journal of Inorganic Biochemistry | Year: 2013

Zinc(II) complexes of a non-steroidal anti-inflammatory drug, mefenamic acid(= Hmef) in the absence or presence of the nitrogen donor heterocyclic ligands 2,2′-bipyridine(= bipy), 2,2′-bipyridylamine(= bipyam), 2,2′-dipyridylketone oxime(= Hpko) or 1,10-phenanthroline(= phen) have been synthesized and characterized. The crystal structures of [Zn(mef-O,O′)2(bipy)], 2, [Zn(mef-O)2(Hpko-N, N′)2]·EtOH, 4 and [Zn(mef-O)(mef-O,O′)(phen) (H2O)], 5, have been determined by X-ray crystallography showing distinct binding modes of mefenamato carboxylato group, bidentate in 2, monodentate in 4 or both in 5. Interaction studies of the complexes with calf-thymus DNA (CT DNA) have shown that complexes can bind to CT DNA with [Zn(mef-O)2(Hpko)2] exhibiting the highest binding constant to CT DNA (Kb = 1.93(± 0.04) × 107 M- 1). The complexes can bind to CT DNA via intercalation as concluded by DNA solution viscosity measurements. Competitive studies with ethidium bromide (EB) have shown that the complexes can displace the DNA-bound EB. The complexes exhibit good binding affinity to serum albumin proteins with [Zn(mef-O)2(H2O)4], 1 exhibiting the highest quenching ability (kq = 1.46 × 1015 M- 1 s- 1 for human and 5.55 × 1015 M- 1 s- 1 for bovine serum albumin). All compounds have been tested for their antioxidant and free radical scavenging activity as well as for their in vitro inhibitory activity against soybean lipoxygenase. The scavenging activity is low to moderate against 1,1-diphenyl-picrylhydrazyl (DPPH) radicals and high against hydroxyl and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radicals, with [Zn(mef-O)2(H 2O)4], 1 (ABTS%, 0.1 mM: 94.75(± 1.06)%OH%, 0.1 mM: 96.69(± 0.27)%; LOX: IC50 = 27.34(± 0.90) μM) exhibiting the highest scavenging activity of the ABTS radical cation among the complexes. Additionally, the complexes exhibit higher scavenging and LOX inhibitory activity than free mefenamic acid (ABTS%, 0.1 mM: 66.32(± 0.38)%OH%,0.1 mM: 92.51(± 0.44)%; LOX: IC50 = 48.52(± 0.88) μM). © 2013 Elsevier Inc.


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.


Tarushi A.,Aristotle University of Thessaloniki | Totta X.,Aristotle University of Thessaloniki | Papadopoulos A.,Alexandrion Technological Educational Institution | Kljun J.,University of Ljubljana | And 3 more authors.
European Journal of Medicinal Chemistry | Year: 2014

The zinc(II) complex of the non-steroidal anti-inflammatory drug tolfenamic acid (=Htolf) in the presence of 2,2′-dipyridylketone oxime (=Hpko) as a N,N′-donor heterocyclic ligand, [Zn(tolf-O)2(Hpko-N,N′) 2]·MeOH (=1·MeOH), has been synthesized and characterized by physicochemical techniques including X-ray crystallography. The complex exhibits good binding affinity to human or bovine serum albumin with high binding constant values. Complex 1 and previously reported Zn-tolfenamato complexes were tested for their free radical scavenging activity and in vitro inhibitory activity against soybean lipoxygenase and exhibited significant activity with [Zn(tolf)2(1,10-phenantroline)] being the most active compound. The complexes interact with calf-thymus (CT) DNA via intercalation, and can displace the DNA-bound ethidium bromide with 1 exhibiting the highest binding constant to CT DNA. © 2014 Elsevier Masson SAS. All rights reserved.


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.


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.
Dalton Transactions | Year: 2010

Cobalt(ii) complexes with the non-steroidal anti-inflammatory drug mefenamic acid in the presence or absence of nitrogen donor heterocyclic ligands (2,2′-bipyridine, 1,10-phenanthroline or pyridine) have been synthesized and characterized with physicochemical and spectroscopic techniques. The experimental data suggest that mefenamic acid acts as deprotonated monodentate ligand coordinated to Co(ii) ion through a carboxylato oxygen. The crystal structures of tetrakis(methanol)bis(mefenamato)cobalt(ii), 1 and (2,2′-bipyridine)bis(methanol)bis(mefenamato)cobalt(ii), 2 have been determined by X-ray crystallography. The EPR spectra of complexes 1 and 2 in frozen solution reveal that they retain their structures. 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 bis(methanol)bis(pyridine)bis(mefenamato) cobalt(ii) exhibits the highest binding constant. 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 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. Mefenamic acid and its cobalt(ii) complexes exhibit good binding propensity to human or bovine serum albumin protein 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. © 2010 The Royal Society of Chemistry.


Dimiza F.,Aristotle University of Thessaloniki | Fountoulaki S.,Aristotle University of Thessaloniki | Papadopoulos A.N.,Alexandrion Technological Educational Institution | Kontogiorgis C.A.,Alexandrion Technological Educational Institution | And 6 more authors.
Dalton Transactions | Year: 2011

Copper(ii) complexes with the non-steroidal antiinflammatory drug mefenamic acid in the presence of aqua or nitrogen donor heterocyclic ligands (2,2′-bipyridine, 1,10-phenanthroline, 2,2′-bipyridylamine or pyridine) have been synthesized and characterized. The crystal structures of [(2,2′-bipyridine)bis(mefenamato)copper(ii)], 2, [(2,2′- bipyridylamine)bis(mefenamato)copper(ii)], 4, and [bis(pyridine)bis(methanol) bis(mefenamato)copper(ii)], 5, have been determined by X-ray crystallography. 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 [bis(aqua)tetrakis(mefenamato) dicopper(ii)] exhibits the highest binding constant to CT DNA. The cyclic voltammograms of the complexes in the presence of CT DNA solution have shown that the complexes can bind to CT DNA by the intercalative binding mode verified also by DNA solution viscosity measurements. Competitive studies with ethidium bromide (EB) indicate that the complexes can displace the DNA-bound EB suggesting strong competition with EB. Mefenamic acid and its complexes exhibit good binding propensity to human or bovine serum albumin protein having relatively high binding constant values. All the compounds have been tested for their antioxidant and free radical scavenging activity as well as for their in vitro inhibitory activity against soybean lipoxygenase showing significant activity. © The Royal Society of Chemistry 2011.


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.


Tolia C.,Aristotle University of Thessaloniki | Papadopoulos A.N.,Alexandrion Technological Educational Institution | Raptopoulou C.P.,Advanced Materials and Processes | Psycharis V.,Advanced Materials and Processes | And 3 more authors.
Journal of Inorganic Biochemistry | Year: 2013

Copper(II) complexes with the non-steroidal antiinflammatory drug flufenamic acid (Hfluf) in the presence of N,N-dimethylformamide (DMF) or nitrogen donor heterocyclic ligands (2,2′-bipyridylamine (bipyam), 1,10-phenanthroline (phen), 2,2′-bipyridine (bipy) or pyridine (py)) have been synthesized and characterized. The crystal structures of [Cu 2(fluf)4(DMF)2], 1, and [Cu(fluf)(bipyam)Cl], 2, have been determined by X-ray crystallography. Density functional theory (DFT) (CAM-B3LYP/LANL2DZ/6-31G**) was employed to determine the structure of complex 2 and its analogues (complexes [Cu(fluf)(phen)Cl], 3, [Cu(fluf)(bipy)Cl], 4 and [Cu(fluf)2(py)2], 5). Time-dependent DFT calculations of doublet-doublet transitions show that the lowest-energy band in the absorption spectrum of 2-5 has a mixed d-d/LMCT character. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that the complexes can bind to CT DNA with [Cu(fluf)(bipy)Cl] exhibiting the highest binding constant to CT DNA. The complexes can bind to CT DNA via intercalation as concluded by studying the cyclic voltammograms of the complexes in the presence of CT DNA solution and by DNA solution viscosity measurements. Competitive studies with ethidium bromide (EB) have shown that the complexes can displace the DNA-bound EB suggesting strong competition with EB. Flufenamic acid and its Cu(II) complexes exhibit good binding affinity to human or bovine serum albumin protein with high binding constant values. All compounds have been tested for their antioxidant and free radical scavenging activity as well as for their in vitro inhibitory activity against soybean lipoxygenase showing significant activity with [Cu(fluf)(phen)Cl] being the most active. © 2013 Elsevier Inc. All rights reserved.


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.

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