Serbian Institute of Chemistry

Belgrade, Serbia

Serbian Institute of Chemistry

Belgrade, Serbia
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Janovic B.S.,Serbian Institute of Chemistry | Collins A.R.,University of Oslo | Vujcic Z.M.,University of Belgrade | Vujcic M.T.,Serbian Institute of Chemistry
Journal of Hazardous Materials | Year: 2017

The aim of this study was to investigate the impact of dyes on DNA before and after enzymatic decolorization by acidic horseradish peroxidase (HRP-A). The comet assay is easy and feasible method widely used to measure DNA damage and repair. The medium-throughput comet assay was employed for assessment of genotoxic effects of 8 dyes in BEAS-2B cells. We have incorporated a digestion with bacterial endonuclease (formamidopyrimidine DNA glycosylase, FPG) to detect oxidized bases in the case of single and double azo dyes, Orange II (OR2) and Amido Black 10B (AB), respectively. This allowed detection 8-oxo-7,8-dihydroguanine, one of most abundant oxidized bases in nuclear DNA. In the case of AB there was no indication of DNA damage, either strand brakes or FPG-sensitive sites before and after decolorization. The OR2 induced DNA damage (in terms of percentage of DNA in comet tails). Also, the frequency of FPG-sensitive sites increased with OR2 concentration. After decolorization no DNA damaging effects was seen at all. The interaction studies of OR2 and AB, before and after decolorization, with calf thymus DNA has been investigated by absorption and fluorescence spectroscopy. The results provide support for the idea that in some cases enzymatic decolorization contributes to lower genotoxicity potential. © 2016 Elsevier B.V.

Dojcinovic B.P.,Serbian Institute of Chemistry | Roglic G.M.,University of Belgrade | Obradovic B.M.,University of Belgrade | Kuraica M.M.,University of Belgrade | And 2 more authors.
Journal of Hazardous Materials | Year: 2011

Decolorization of reactive textile dyes Reactive Black 5, Reactive Blue 52, Reactive Yellow 125 and Reactive Green 15 was studied using advanced oxidation processes (AOPs) in a non-thermal plasma reactor, based on coaxial water falling film dielectric barrier discharge (DBD). Used initial dye concentrations in the solution were 40.0 and 80.0mg/L. The effects of different initial pH of dye solutions, and addition of homogeneous catalysts (H2O2, Fe2+ and Cu2+) on the decolorization during subsequent recirculation of dye solution through the DBD reactor, i.e. applied energy density (45-315kJ/L) were studied. Influence of residence time was investigated over a period of 24h. Change of pH values and effect of pH adjustments of dye solution after each recirculation on the decolorization was also tested. It was found that the initial pH of dye solutions and pH adjustments of dye solution after each recirculation did not influence the decolorization. The most effective decolorization of 97% was obtained with addition of 10mM H2O2 in a system of 80.0mg/L Reactive Black 5 with applied energy density of 45kJ/L, after residence time of 24h from plasma treatment. Toxicity was evaluated using the brine shrimp Artemia salina as a test organism. © 2011 Elsevier B.V.

Mentus S.,University of Belgrade | Mentus S.,Serbian Academy of Science and Arts | Abu Rabi A.,Serbian Institute of Chemistry | Jasin D.,Technical School Zrenjanin
Electrochimica Acta | Year: 2012

By multiple potentiodynamic polarization of polished titanium surface in an aqueous PdCl 2 solution, a thin composite Pd/TiO 2 layer was formed, consisting of Pd submicron particles grown through a nanometer-thin surface TiO 2 layer. The real surface area of Pd was determined by cyclic voltammetry in nitrogen purged 0.1 mol dm -3 HClO 4. The oxygen reduction reaction on the Pd/TiO 2 layer in 0.1 mol dm -3 KOH and 0.1 mol dm -3 HClO 4 solutions has been studied using rotating disc electrode (RDE) voltammetry. Comparing to the best palladium or palladium based catalysts published thus far, the Pd/TiO 2 composite yielded similar or higher (in acidic solution) or discernible higher (in alkaline solution) rate of oxygen reduction. This was found to be mostly due to the high surface area of Pd particles, but, to some extent, due to the influence of TiO 2 support itself. © 2012 Elsevier Ltd.

Dimitric Markovic J.M.,University of Belgrade | Markovic Z.S.,State University of Novi Pazar | Brdaric T.P.,Serbian Institute Kirilo Savic | Pavelkic V.M.,Serbian Institute Kirilo Savic | Jadranin M.B.,Serbian Institute of Chemistry
Food Chemistry | Year: 2011

Combined spectroscopic (UV/visible, Raman, MS) and theoretical approaches were used to assess interaction of iron(III) with quercetin and baicalein in aqueous buffered solutions. Obtained results implicated formation of two iron quercetin complexes, with pH-dependent stoichiometries of 1:2 and 1:1, and one iron baicalein complex with stoichiometry of 1:1. Results of vibrational analysis and theoretical calculations implicated 3-hydroxy-4-carbonyl and the 3′-hydroxy-4′-hydroxy group of catechol as chelating sites for quercetin. For baicalein 5-hydroxy-6-hydroxy group is energetically the most favourable, although 5-hydroxy-4-carbonyl and 6-hydroxy-7-hydroxy chelating sites are energetically similar. Antiradical activity, reaction stoichiometry and number of inactivated DPPH molecules per mole of antioxidant indicated quercetin as a better antioxidant than its iron complex, baicalein and iron baicalein complex. The same structural features appeared to be important both in complexation and antioxidant activity. The equilibrium geometries, optimised using the B3LYP/6-31G (d, p) level of theory, predicted structural modifications between the ligand molecules in free state and in the complex structures. Correlation between experimental and theoretical results was very good. © 2011 Elsevier Ltd. All rights reserved.

Husinec S.,Serbian Institute of Chemistry | Markovic R.,University of Belgrade | Petkovic M.,University of Belgrade | Nasufovic V.,University of Belgrade | Savic V.,University of Belgrade
Organic Letters | Year: 2011

Chemical equations presented. A base promoted cyclization of the protected N-propargylaminopyridines was shown to be an efficient method for the preparation of imidazo[1,2-a]pyridine derivatives. The reactions were carried out with a small excess of base, at room temperature or slightly above producing the heterocyclic products in moderate to good yields. The stereoelectronic properties of substituents on the pyridine ring were shown to influence the cyclization process. © 2011 American Chemical Society.

Gorjanovic S.Z.,Serbian Institute of General and Physical Chemistry | Novakovic M.M.,Serbian Institute of Chemistry | Potkonjak N.I.,Serbian Institute of General and Physical Chemistry | Ida L.-C.,University of Belgrade | Suznievic D.Z.,Serbian Institute of General and Physical Chemistry
Journal of Agricultural and Food Chemistry | Year: 2010

A novel antioxidative assay based on direct current polarography has been developed. Quantification of antioxidative (AO) activity has been based on a decrease of hydrogen peroxide anodic current in the presence of antioxidants. An efficient experimental procedure, without any special pretreatment of analyzed samples, has been applied. Antioxidative activity of different kinds of commercial beers (dark, blond, and alcohol-free), some small-scale made special beers with medicinal herbs and mushroom extracts, extracts themselves, as well as individual phenolic components present in beer has been measured. In addition, changes of AO activity during the full-scale industrial process of beer production have been monitored. A strong correlation between results obtained and total phenolics content has been observed. The assay can be recommended for application in brewing industry, either to survey a process with the aim to optimize relevant technological factors or to analyze quality of final product. © 2009 American Chemical Society.

Andjelkovic U.,Serbian Institute of Chemistry | Picuric S.,Goethe University Frankfurt | Vujcic Z.,University of Belgrade
Food Chemistry | Year: 2010

Four external invertase isoforms (EINV1, EINV2, EINV3 and EINV4) from Saccharomyces cerevisiae were highly purified by isoelectric precipitation, ethanol precipitation, ion-exchange on QAE-Sephadex and gel filtration using Sephacryl S-200. Unlike previously published procedures for external invertase purification, a specially designed step elution was applied on QAE-Sephadex which enabled the separation of four isoforms. The isoforms have the same molecular mass and catalytic properties: Km for sucrose (25.6 mM), pH optimum (3.5-5.0) and temperature optimum (60 °C), but they exhibit significant difference in pI values, thermal stability and chemical reactivity. Deglycosylation studies showed that the observed differences between isoforms arise from posttranslational modifications. Results showed that external invertase is a mixture of at least four isoforms, but in order to improve the efficiency of food industry processes, only the most stable isoform (EINV1) should be purified and utilised. Substantially different chemical reactivity of the isoforms could be used to improve the yield of covalent immobilization procedures. © 2009 Elsevier Ltd. All rights reserved.

Janjic G.V.,Serbian Institute of Chemistry | Veljkovic D.Z.,Serbian Institute of Chemistry | Zaric S.D.,University of Belgrade
Crystal Growth and Design | Year: 2011

Analysis of crystal structures from the Cambridge Structural Database (CSD) and high level ab initio calculations reveals that the water/aromatic parallel alignment interactions, where the water molecule or one of its O-H bonds is parallel to the aromatic ring plane, can be significantly strong at large horizontal displacements. We found out that the strongest energies of the interactions are calculated for the water position with the large horizontal displacements, out of the aromatic ring and out of the C-H bond region. For calculated systems, normal distances were decreasing with increasing the horizontal displacement, in accord with the data found in crystal structures. The calculated energies of the interactions are significant, up to δE CCSD(T)(limit) = -10.25 kJ/mol (at a horizontal displacement of 2.6 Å), and comparable with the energy of the slipped-parallel benzene/benzene dimer. Both dispersion and electrostatic components of the interaction energy are important. The calculated interaction energies reveal that also at long horizontal displacements of 3.5 Å, interaction is substantially strong, up to δECCSD(T)(limit) = -6.23 kJ/mol. The data show the existence of the water/aromatic parallel alignment interactions in crystal structures and indicate their importance for various systems. © 2011 American Chemical Society.

Stijepovic M.Z.,Texas A&M University at Qatar | Linke P.,Texas A&M University at Qatar | Papadopoulos A.I.,Center for Research and Technology Hellas | Grujic A.S.,Serbian Institute of Chemistry
Applied Thermal Engineering | Year: 2012

The performance of ORC systems strongly depends on working fluid properties. We explore the relationships between working fluid properties and ORC common economic and thermodynamic performance criteria from a theoretical and an analytical point of view. The mapping of individual properties and performance criteria presented in this paper will provide a basis for the development of efficient and systematic strategies and approaches for ORC working fluid selection in future. © 2011 Published by Elsevier Ltd. All rights reserved.

Gorjanovic S.Z.,Serbian Institute of General and Physical Chemistry | Novakovic M.M.,Serbian Institute of Chemistry | Potkonjak N.I.,Serbian Institute of General and Physical Chemistry | Suznjevic D.Z.,Serbian Institute of General and Physical Chemistry
Journal of Agricultural and Food Chemistry | Year: 2010

Antioxidant (AO) activity of various red and white wines of different origin as well as some individual phenolic compounds present in wine has been assessed using a polarographic assay. Direct current polarography has been used to survey hydrogen peroxide scavenge (HPS) upon gradual addition of tested samples. Results expressed as reciprocal value of wine volume required for 50% decrease of anodic limiting current of hydrogen peroxide have been validated through correlation with Folin-Ciocalteau and DPPH assays. All wines exhibit HPS activity analogous with total phenolic content and DPPH scavenge. Reliability and accuracy, low cost, and rapid and direct experimental procedure open a wide area for application of this assay, making it a good alternative to standard, widely accepted AO assays. © 2010 American Chemical Society.

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