JSCS Vol 72, No. 10
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J. Serb.
Chem. Soc. 72 (10) 921–939 (2007)
UDC
547.814.5:541.572.54:541.515:543.062, JSCS–3624, doi: 10.2298/JSC0710921M; Review paper
Review
Investigation
of metal–flavonoid chelates and the determination of flavonoids via
metal–flavonoid complexing reactions
DUSAN MALESEV and VESNA
KUNTIC
(Received 2 June 2006, revised 4 April
2007)
Flavonoids
constitute a large group of polyphenolic phytochemicals with antioxidant
properties which are overwhelmingly exerted through direct free radical
scavenging. Flavonoids also exhibit antioxidant properties through chelating
with transition metals, primarily Fe(II), Fe(III) and Cu(II), which participate
in reactions generating free radicals. Metal–flavonoid chelates are
considerably more potent free radical scavengers than the parent flavonoids and
play a prominent role in protecting from oxidative stress. To unravel the
origin of their potent biological action extensive physico–chemical studies
were undertaken to reveal the chemical structure, chelation sites, assess the
impact of the metal/ligand ratio on the structure of the complexes and the
capacity of flavonoids to bind metal ions. In spite of such extensive efforts,
data on the composition, structure and complex-formation properties are
incomplete and sometimes even contradictory. The aim of this paper is to give a
personal account on the development of the field through a retrospective
evaluation of our own research which covers approximately 40 complexes of
flavonoids from different flavonoids subclasses (rutin, quercetin,
3-hydroxyflavone, morin and hesperidin) with several metal ions or groups and
suggest directions for future research. Special emphasis will be given to the
site of the central ion, the composition of the complexes, the role of pH in
complex formation, the stability of metal–flavonoid complexes and their
potential application for analytical purposes.
Keywords: flavonoids, chelates, free
radical scavengers, stability constants, quantitative analysis.
Full Article - PDF 300 KB
J. Serb.
Chem. Soc. 72 (10) 941–944 (2007)
UDC 547.21+547.313:66.094.3:628–032.2,
JSCS–3625, doi: 10.2298/JSC0710941O; Short communication
A mild and effective method for the
conversion of alkenes into alcohols in subcritical water
Mersin University, Department of Chemistry,
(Received
Alkenes were oxidized to alcohols in subcritical water. A number of
alkenes were oxidized directly to their alcohols in excellent yields. The
syntheses were performed in 215 cm3 stainless steel high pressure
reactor at 120 ºC in 150 cm3 water. The yields of alcohols increased
with the nitrogen pressure.
Keywords: alkene, alcohol, subcritical water, oxidation.
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J. Serb.
Chem. Soc. 72 (10) 945–952 (2007)
UDC 54–78+577.15:546.714:577.11,
JSCS–3626, doi: 10.2298/JSC0710945N; Original scientific paper
Do altered activities of superoxide dismutases and the
level of NF-kB modulate the effects of gAMma radiation in HeLaS3
cells?
ANA NICIFOROVIC,
MIROSLAV ADZIC, SNEZANA D. SPASIC* and MARIJA B. RADOJCIC
Department of Molecular Biology and
Endocrinology, Vinča Institute of Nuclear Sciences,
*Centre of Chemistry, ICTM,
(Received
Most
experimental models, including cell culture studies, have demonstrated that
over-expression of manganese superoxide dismutase (MnSOD) in cells bearing a
carcinoma phenotype has anti-proliferative and tumour suppression characteristics.
In contrast, when cervical carcinoma biopsies express MnSOD, there is a poor
prognosis and resistance to radiation therapy. The results herein indicate that
human cervical adenocarcinoma (HeLaS3) cells have increased MnSOD activity (up
to 50 % of the total SOD activity) due to low expression of its repressor
p53 and a high level of oxidative stress arising from the cell culture
conditions. High MnSOD activity may be related to HeLaS3 cell radioresistance,
illustrated by a high IC50 of 3.4 Gy and by a relatively high
level of cell viability after gAMma irradiation. In contrast to MnSOD activity,
cytosolic CuZnSOD activity decreased after ionising radiation. The catalase
(Cat) activity was unchanged. IR also increased the nitric oxide synthase
(NOS) activity. Such conditions lead to increased concentrations of the
superoxide radical, hydrogen peroxide and NO., which together may be
responsible for the decreased expression of NF-kB and
unaltered Cat activity. Therefore, the disturbed redox balance within HeLaS3
cells may be responsible for the cytotoxicity observed at higher irradiation doses.
It could be concluded that inhibition of the CuZnSOD activity may be an
important target for the selective killing of radioresistant cancer cells.
Keywords:
gAMma irradiation, antioxidant enzymes, NF-kB,
p53, HeLaS3 cells.
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J. Serb. Chem. Soc. 72 (10) 953–959
(2007)
UDC 634.46:665.666.5:577.1, JSCS–3627, doi: 10.2298/JSC0710953K; Original scientific paper
Biochemical
changes in cuttings of Robinia pseudoacacia after treatment with naphthenate
SLAVKO KEVRESAN, BRANISLAV
KOVACEVIC*, VERA CIRIN–NOVTA**, KSENIJA KUHAJDA**, JULIJAN KANDRAC, KSENIJA
PAVLOVIC** and LJUBICA GRBOVIC**
Faculty of Agriculture,
*
**Department of
Chemistry, Faculty of Sciences, University of Novi Sad, Trg D. Obradovica 3,
21000 Novi Sad, Serbia
(Received
Naphthenic
acids were isolated from gas oil fractions (distillation interval 168–290 °C) of Vojvodina crude oil “Velebit”, characterized and
their biological activity evaluated by the biochemical changes in cuttings of Robinia
pseudoacacia after treatment with naphthenate. The activities of IAA
peroxidase, total peroxidases and AMylase, as well as the contents of
reducing sugars and total proteins, were determined in the basal parts of soft
wood cuttings of black locust after treatment with sodium naphthenate or the
sodium salt of 1-naphthaleneacetic acid (NAA), concentration 10-7
mol dm-3 for 3 or 6 h. High activities of IAA oxidase and
AMylase, together with a low activity of peroxidase (which is known as being
stimulatory for the initiation and
activation of primordia) were obtained after the three-hour treatment
with sodium naphthenate. Six-hour treatment had an inhibitory effect on the
exAMined biochemical markers. The effects of three- and six-hour treatments with NAA were between those of the corresponding
treatment with naphthenic acids.
Keywords:
naphthenate, rooting, biochemical markers, black locust.
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UDC *Eryngium+543.64:665.52(497.11),
JSCS–3628, doi: 10.2298/JSC0710961C; Original scientific paper
Essential oil analysis of two endemic
Eryngium species from
HRYSOSTOMOS CAPETANOS, VASILIKI SAROGLOU, PETAR D. MARIN*, ANA SIMIC*
and HELEN D. SKALTSA
Division of Pharmacognosy and Chemistry of Natural Products, School of Pharmacy,
University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece
*Faculty of Biology, Institute of Botany and Botanical Garden
“Jevremovac”, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia
(Received
The
volatile composition of two Eryngium
species was studied. The essential oils were obtained by hydrodistillation in
a modified Clevenger-type apparatus, and their analyses were performed by GC
and GC–MS. A total of 58 different compounds were identified. Their main constituents were as follows: E.
serbicum: germacrene D (19.7 %), b-elemene (10.0 %)
and spathulenol (6.9 %); E.
palmatum: sesquicineole (21.3 %), caryophyllene oxide (16.0 %), spathulenol (16.0 %) and sabinene
(5.5 %). The main portion
in both studied taxa consisted of sesquiterpenes.
Keywords: E. palmatum
Vis. et Pančić, E. serbicum
Pančić, Apiaceae, volatile constituents,
sesquiterpene hydrocarbons.
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J. Serb.
Chem. Soc. 72 (10) 967–973 (2007)
UDC 54–724+537.872:532.74+539.194,
JSCS–3629, doi: 10.2298/JSC0710967G; Original
scientific paper
The McClelland approximation and the distribution of
π-electron molecular orbital energy levels
IVAN GUTMAN
Faculty of Science,
(Received
The total π-electron energy E of a conjugated hydrocarbon with n
carbon atoms and m carbon–carbon bonds can be approximately calculated
by means of the McClelland formula E » g(2mr)1/2, where g is an
empirical fitting constant, g ≈ 0.9. It was claimed that
the good quality of the McClelland approximation is a consequence of the fact
that the π-electron molecular orbital energy levels are distributed in a
nearly uniform manner. It will now be shown that the McClelland approximation
does not depend on the nature of the distribution of energy levels, i.e.,
that it is compatible with a large variety of such distributions.
Keywords: total π-electron energy, McClelland formula,
Hückel molecular orbital theory.
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J. Serb. Chem. Soc. 72 (10) 975–981 (2007)
UDC 547.756+546.732’742’562’47’982’49:543.4/.5, JSCS–3630, doi: 10.2298/JSC0710975K; Original scientific paper
Spectrophotometric
study of Co(II), Ni(II), Cu(II), Zn(II), Pd(II) and Hg(II) complexes with
isatin- β-thiosemicarbazone
SANDRA S. KONSTANTINOVIC, BLAGA C.
RADOVANOVIC*, ZORAN B. TODOROVIC and SLAVICA B. ILIC
Faculty of Technology, Bulevar Oslobodjenja
124, 16000
*Faculty of Science, Department of Chemistry,
Višegradska 33, 18000
(Received
The composition and stability of the complexes of isatin-b-thiosemicarbazone with Co(II), Ni(II), Cu(II), Zn(II), Pd(II) and
Hg(II) have been investigated using spectrophotometric method at 30 °C and constant ionic strength of 0.1 mol dm-3
(KNO3) in 70 % ethanol. Experimental results indicate the
formation of MeL and MeL2 complexes
for Ni(II) and Co(II), and MeL for Cu(II), Zn(II), Pd(II) and Hg(II)
complexes, whose stability constants, bn, have been
calculated using a computerized iterative method of successive approximation.
Keywords: isatin-b-thiosemicarbazone, complexes, spectrophotometric
study, stability constant.
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J. Serb. Chem. Soc. 72 (10) 983–992 (2007)
UDC 542.9+547.571+547.351+546.562:615.28.001.5, JSCS– 3631, doi: 10.2298/JSC0710983R; Original scientific paper
DNA cleavage,
structural elucidation and anti-microbial studies of three novel mixed ligand
Schiff base complexes of copper(II)
N. RAMAN and S. JOHNSON RAJA
Research Department of Chemistry,
(Received
Three new copper complexes of mixed ligands
derived from Schiff bases (condensation of p-AMinoacetanilide
and substituted benzaldehydes) with 1,10-phenanthroline have been synthesized
and characterized by elemental analysis, IR, UV–Vis, magnetic moments,
conductivity and electrochemical measurements. The spectral techniques suggest
that all the copper complexes exhibit octahedral geometry. The low electrical
conductance of the complexes supports their neutral nature. The monomeric nature
of the complexes was assessed from their magnetic susceptibility values. The in vitro biological screening effects of
the investigated compounds were tested against the bacteria Escherichia coli, Staphylococcus aureus, and Salmonella
typhi and the fungi Rhizopus
stolonifer and Candida albicans
by the serial dilution method. A comparative study of the MIC values of the
Schiff bases and their copper complexes indicates that the metal complexes
exhibited higher antibacterial activity than the free ligands. The DNA cleavage
ability of the complexes was monitored by the gel electrophoresis technique. It
was found that electron withdrawing group substituted copper complex had higher
DNA cleavage activity than the other copper complexes.
Keywords: p-AMinoacetanilide, benzaldehyde, p-methoxybenzaldehyde,
2-chlorobenzaldehyde, CT DNA, copper(II) complexes.
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J. Serb. Chem. Soc. 72 (10) 993–1002 (2007)
UDC 541.135.5–039.26.004.12+546.811, JSCS– 3632, doi: 10.2298/JSC0710993S; Original scientific paper
Preparation
and characterization of carbon paste electrode modified with tin and
hexacyanoferrate ions
REZA E. SABZI, ALL HASANZADEH, KHOSROW
GHASEMLU and PARVANEH HERAVI
Department of Chemistry, Faculty of Science,
(Received
A carbon paste electrode was modified
chemically using Sn(II) or Sn(IV) chlorides and hexacyanoferrate(II) or
hexacyanoferrate(III). The electrochemical behavior of such SnHCF carbon paste
electrodes was studied by cyclic voltAMmetry. The study revealed that Sn(IV)
and hexacyanoferrate(II) yield the best results. This electrode showed one pair
of peaks: the anodic and cathodic peak at the potentials of 0.195 and 0.154 V
vs. SCE, respectively, at a scan rate of 20 mV s-1 in a 0.5 M phosphate
buffer as the supporting electrolyte. The SnHCF modified electrodes were very
stable under potential scanning. The effects of pH and alkali metal cations of
the supporting electrolyte on the electrochemical characteristics of the
modified electrode were studied. The results showed that cations have a
considerable effect on the electrochemical behavior of the modified electrode.
The diffusion coefficients of hydrated K+ and Na+ in the
film, the transfer coefficient and the electron transfer rate constant were
determined.
Keywords: carbon paste electrode, modified electrode, tin, hexacyanoferrate.
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J. Serb. Chem. Soc. 72 (10) 1003–1013
(2007)
UDC 577.112.386+546.33+546.712:543.552:544.35, JSCS–3633, 10.2298/JSC0710003B; Original scientific paper
VoltAMmetric
study of the interaction between oxacillin sodium and cysteine in the presence
and absence of Mn(II) ions in neutral buffer solution
ENDER BİÇER* and EMİNE COŞKUN
(Received
In this study, the voltAMmetric behaviour of
the interaction of oxacillin sodium (OXA) and OXA–cysteine (RSH) was studied by
square-wave voltAMmetry, cyclic voltAMmetry in Britton–Robinson (B–R) buffer (pH
7.0). OXA gave two peaks at –0.248 and –1.224 V. For the interaction, the peak
of mercurous cysteine thiolate (Hg2(SR)2) was selected.
It was found that the peak currents corresponding to Hg2(SR)2
significantly decreased, while the peak potential shifted to more positive
potentials upon the addition of OXA. The observed phenomena are due to the
interaction of OXA with RSH on the surface of the mercury electrode. When OXA
was added to the electrochemical cell along with Mn(II), new peaks at –0.146
and –0.608 V were observed. These peaks were due to the catalytic activity of
OXA on the reduction of Mn(II) and could be attributed to the formation of
Mn(II) complexes with different metal/ligand ratios. On the other hand, in the
presence of RSH, the peak at –0.608 V vanished and a reduction peak was
observed at –0.662 V. The catalytic reduction peak potential of Mn(II) at
–0.662 V indicated that RSH slightly prevented the catalysis process of OXA due
to their mutual interaction.
Keywords: voltAMmetry, oxacillin, cysteine, interaction.
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UDC 546.161+547.212:66.048+532.55:536.24, JSCS–3634, doi: 10.2298/JSC0710015D; Original scientific paper
Pressure
drop during evaporation of 1,1,1,2-tetrafluoroethane (R-134a) in a plate heat
exchanger
EMILA DJORDJEVIC, STEPHAN KABELAC* and
SLOBODAN SERBANOVIC
Faculty of Technology and Metallurgy,
*
(Received
Experimental results for the pressure drop
during the evaporation of the refrigerant 1,1,1,2-tetrafluoroethane (R-134a) in
a vertical plate heat exchanger are presented in this paper. The influences of
mass flux, heat flux and vapor quality on the two-phase pressure drop are
specially analyzed and compared with previously published experimental data and
literature correlations. All results are given in graphical form as the
dependency of the frictional pressure drop on the mean vapor quality.
Keywords: plate heat exchanger, evaporation, 1,1,1,2-tetrafluoroethane, pressure
drop.
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J. Serb. Chem. Soc. 72 (10) 1023–1030 (2007)
UDC 620.261:66.017+621.793.7:539.196:67.017, JSCS–3635, doi: 10.2298/JSC0710023D; Original scientific paper
The use
of image analysis for the study of interfacial bonding in solid composite
propellant
JASMINA DOSTANIC, GORDANA USCUMLIC, TATJANA
VOLKOV–HUSOVIC, RADMILA JANCIC–HEINEMANN and DUSAN MIJIN
Faculty of Technology and Metallurgy,
(Received 6 July 2006)
In the frAMework of this research, the progrAM
Image Pro Plus was applied for determining the polymer–oxidizer interactions in
HTPB-based composite propellants. In order to improve the interactions,
different bonding agents were used, and their efficiency was analyzed. The
determination of the quantity, area and radius of non-bonded oxidizer crystals
is presented. The position of formed cracks in the specimen and their area has
a great influence on the mechanical properties of composite propellant. The
preparation of the composite propellant in order to enable the photographing of
their structure by means of stereoscopic and metallographic microscopes with
the digital cAMera is also described as well.
Key words: composite propellant, interactions, grain distribution, dewetting, image
analysis, mechanical properties.
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UDC 535.65+543.26:547.412.123+623.459.42, JSCS–3636, doi: 10.2298/JSC0710031P; Original scientific paper
A
simple in situ visual and tristimulus
colorimetric method for the determination of diphosgene in air
VLADIMÍR PITSCHMANN, ZBYNĚK KOBLIHA*, EMIL
HALÁMEK* and IVANA TUŠAROVÁ
Oritest spol. s r.o., StaroprAMenná 17, 150 00 Praha
5, Czech Republic
*NBC Defense Institute,
(Received
A simple visual and tristimulus colorimetric
method (three-dimensional system CIE–L*a*b*) for the determination of trace
AMounts of diphosgene in air has been developed. The method is based on the
suction of diphosgene vapors through a modified cotton fabric filter fixed in a
special adapter. Prior to analysis, the filter is saturated with a chromogenic
reagent based on 4-(p-nitrobenzyl)pyridine.
The optimal composition of the reagent is 2 g of 4-(p-nitrobenzyl)pyridine and 4 g of N-phenylbenzylAMine in 100 ml of a 50:50 ethanol–glycerol mixture.
The intensity of the formed red coloration of the filter is evaluated visually
or by a tristimulus colorimeter (LMG 173,
Keywords: tristimulus colorimetry, diphosgene, air analysis,
4-(p-nitrobenzyl)pyridine, N-phenylbenzylAMine.
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&AMp; copy; SHD 2007.
For more information contact: JSCS@tmf.bg.ac.yu