TY  - JOUR
AU  - Korać Jačić, Jelena
AU  - Stanković, Dalibor M.
AU  - Stanić, Marina
AU  - Bajuk-Bogdanović, Danica
AU  - Žižić, Milan
AU  - Bogdanović Pristov, Jelena
AU  - Grguric-Sipka, Sanja
AU  - Popovic-Bijelic, Ana
AU  - Spasojević, Ivan
PY  - 2018
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1138
AB  - Coordinate and redox interactions of epinephrine (Epi) with iron at physiological pH are essential for understanding two very different phenomena - the detrimental effects of chronic stress on the cardiovascular system and the cross-linking of catecholamine-rich biopolymers and frameworks. Here we show that Epi and Fe3+ form stable high-spin complexes in the 1:1 or 3:1 stoichiometry, depending on the Epi/Fe3+ concentration ratio (low or high). Oxygen atoms on the catechol ring represent the sites of coordinate bond formation within physiologically relevant bidentate 1:1 complex. Redox properties of Epi are slightly impacted by Fe3+. On the other hand, Epi and Fe2+ form a complex that acts as a strong reducing agent, which leads to the production of hydrogen peroxide via O-2 reduction, and to a facilitated formation of the Epi-Fe3+ complexes. Epi is not oxidized in this process, i.e. Fe2+ is not an electron shuttle, but the electron donor. Epi-catalyzed oxidation of Fe2+ represents a plausible chemical basis of stress-related damage to heart cells. In addition, our results support the previous findings on the interactions of catecholamine moieties in polymers with iron and provide a novel strategy for improving the efficiency of cross-linking.
PB  - Nature Publishing Group, London
T2  - Scientific Reports
T1  - Coordinate and redox interactions of epinephrine with ferric and ferrous iron at physiological pH
VL  - 8
DO  - 10.1038/s41598-018-21940-7
ER  - 

@article{
author = "Korać Jačić, Jelena and Stanković, Dalibor M. and Stanić, Marina and Bajuk-Bogdanović, Danica and Žižić, Milan and Bogdanović Pristov, Jelena and Grguric-Sipka, Sanja and Popovic-Bijelic, Ana and Spasojević, Ivan",
year = "2018",
abstract = "Coordinate and redox interactions of epinephrine (Epi) with iron at physiological pH are essential for understanding two very different phenomena - the detrimental effects of chronic stress on the cardiovascular system and the cross-linking of catecholamine-rich biopolymers and frameworks. Here we show that Epi and Fe3+ form stable high-spin complexes in the 1:1 or 3:1 stoichiometry, depending on the Epi/Fe3+ concentration ratio (low or high). Oxygen atoms on the catechol ring represent the sites of coordinate bond formation within physiologically relevant bidentate 1:1 complex. Redox properties of Epi are slightly impacted by Fe3+. On the other hand, Epi and Fe2+ form a complex that acts as a strong reducing agent, which leads to the production of hydrogen peroxide via O-2 reduction, and to a facilitated formation of the Epi-Fe3+ complexes. Epi is not oxidized in this process, i.e. Fe2+ is not an electron shuttle, but the electron donor. Epi-catalyzed oxidation of Fe2+ represents a plausible chemical basis of stress-related damage to heart cells. In addition, our results support the previous findings on the interactions of catecholamine moieties in polymers with iron and provide a novel strategy for improving the efficiency of cross-linking.",
publisher = "Nature Publishing Group, London",
journal = "Scientific Reports",
title = "Coordinate and redox interactions of epinephrine with ferric and ferrous iron at physiological pH",
volume = "8",
doi = "10.1038/s41598-018-21940-7"
}

Korać Jačić, J., Stanković, D. M., Stanić, M., Bajuk-Bogdanović, D., Žižić, M., Bogdanović Pristov, J., Grguric-Sipka, S., Popovic-Bijelic, A.,& Spasojević, I.. (2018). Coordinate and redox interactions of epinephrine with ferric and ferrous iron at physiological pH. in Scientific Reports
Nature Publishing Group, London., 8.
https://doi.org/10.1038/s41598-018-21940-7

Korać Jačić J, Stanković DM, Stanić M, Bajuk-Bogdanović D, Žižić M, Bogdanović Pristov J, Grguric-Sipka S, Popovic-Bijelic A, Spasojević I. Coordinate and redox interactions of epinephrine with ferric and ferrous iron at physiological pH. in Scientific Reports. 2018;8.
doi:10.1038/s41598-018-21940-7 .

Korać Jačić, Jelena, Stanković, Dalibor M., Stanić, Marina, Bajuk-Bogdanović, Danica, Žižić, Milan, Bogdanović Pristov, Jelena, Grguric-Sipka, Sanja, Popovic-Bijelic, Ana, Spasojević, Ivan, "Coordinate and redox interactions of epinephrine with ferric and ferrous iron at physiological pH" in Scientific Reports, 8 (2018),
https://doi.org/10.1038/s41598-018-21940-7 . .

TY  - JOUR
AU  - Kucirkova, Tereza
AU  - Stiborek, Marek
AU  - Ducka, Monika
AU  - Navratilova, Jarmila
AU  - Bogdanović Pristov, Jelena
AU  - Popovic-Bijelic, Ana
AU  - Vojvodić, Snežana
AU  - Preisler, Jan
AU  - Kanicky, Viktor
AU  - Smarda, Jan
AU  - Spasojević, Ivan
AU  - Benes, Petr
PY  - 2018
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1156
AB  - Wedelactone (WL), a plant polyphenolic derivative of coumestan, represents a promising anti-cancer agent. The underlying mechanisms of its action are not fully understood and appear to involve interplay with copper ions. Herein, we examined coordination and redox interactions of WL with Cu2+ in phosphate buffer (pH 7), and in two breast cancer cell lines. EPR, UV-Vis and fluorescence spectroscopy showed that WL and Cu2+ build a coordination complex with 2:1 stoichiometry and distorted tetrahedral geometry. WL showed strong fluorescence that was quenched by Cu2+. The sequestration of the intracellular copper pool with neocuproine led to a significant drop in the cytotoxic effects of WL, whereas the co-application of Cu2+ and WL and the formation of an extracellular complex suppressed both the cytotoxic effects of WL and copper loading. Fluorescence microscopy showed that WL is mainly localized in the cytosol and significantly less in the nuclei. WL fluorescence was stronger in cells pretreated with neocuproine, implying that the complex of WL and Cu2+ is formed inside the cells. WL caused a two-fold increase in the lysosomal level of copper as well as copper-dependent lysosome membrane permeabilization. On the other hand, the protective effects of overexpression of thioredoxin 1 imply that WL exerts the main oxidative impact inside the nucleus. The interactions of WL with copper may be essential for therapeutic performance and selectivity against cancer cells, taking into account that a number of cancer types, including breast cancer, exhibit increased intratumoral copper levels or altered copper distribution.
PB  - Royal Soc Chemistry, Cambridge
T2  - Metallomics
T1  - Anti-cancer effects of wedelolactone: interactions with copper and subcellular localization
EP  - 1531
IS  - 10
SP  - 1524
VL  - 10
DO  - 10.1039/c8mt00191j
ER  - 

@article{
author = "Kucirkova, Tereza and Stiborek, Marek and Ducka, Monika and Navratilova, Jarmila and Bogdanović Pristov, Jelena and Popovic-Bijelic, Ana and Vojvodić, Snežana and Preisler, Jan and Kanicky, Viktor and Smarda, Jan and Spasojević, Ivan and Benes, Petr",
year = "2018",
abstract = "Wedelactone (WL), a plant polyphenolic derivative of coumestan, represents a promising anti-cancer agent. The underlying mechanisms of its action are not fully understood and appear to involve interplay with copper ions. Herein, we examined coordination and redox interactions of WL with Cu2+ in phosphate buffer (pH 7), and in two breast cancer cell lines. EPR, UV-Vis and fluorescence spectroscopy showed that WL and Cu2+ build a coordination complex with 2:1 stoichiometry and distorted tetrahedral geometry. WL showed strong fluorescence that was quenched by Cu2+. The sequestration of the intracellular copper pool with neocuproine led to a significant drop in the cytotoxic effects of WL, whereas the co-application of Cu2+ and WL and the formation of an extracellular complex suppressed both the cytotoxic effects of WL and copper loading. Fluorescence microscopy showed that WL is mainly localized in the cytosol and significantly less in the nuclei. WL fluorescence was stronger in cells pretreated with neocuproine, implying that the complex of WL and Cu2+ is formed inside the cells. WL caused a two-fold increase in the lysosomal level of copper as well as copper-dependent lysosome membrane permeabilization. On the other hand, the protective effects of overexpression of thioredoxin 1 imply that WL exerts the main oxidative impact inside the nucleus. The interactions of WL with copper may be essential for therapeutic performance and selectivity against cancer cells, taking into account that a number of cancer types, including breast cancer, exhibit increased intratumoral copper levels or altered copper distribution.",
publisher = "Royal Soc Chemistry, Cambridge",
journal = "Metallomics",
title = "Anti-cancer effects of wedelolactone: interactions with copper and subcellular localization",
pages = "1531-1524",
number = "10",
volume = "10",
doi = "10.1039/c8mt00191j"
}

Kucirkova, T., Stiborek, M., Ducka, M., Navratilova, J., Bogdanović Pristov, J., Popovic-Bijelic, A., Vojvodić, S., Preisler, J., Kanicky, V., Smarda, J., Spasojević, I.,& Benes, P.. (2018). Anti-cancer effects of wedelolactone: interactions with copper and subcellular localization. in Metallomics
Royal Soc Chemistry, Cambridge., 10(10), 1524-1531.
https://doi.org/10.1039/c8mt00191j

Kucirkova T, Stiborek M, Ducka M, Navratilova J, Bogdanović Pristov J, Popovic-Bijelic A, Vojvodić S, Preisler J, Kanicky V, Smarda J, Spasojević I, Benes P. Anti-cancer effects of wedelolactone: interactions with copper and subcellular localization. in Metallomics. 2018;10(10):1524-1531.
doi:10.1039/c8mt00191j .

Kucirkova, Tereza, Stiborek, Marek, Ducka, Monika, Navratilova, Jarmila, Bogdanović Pristov, Jelena, Popovic-Bijelic, Ana, Vojvodić, Snežana, Preisler, Jan, Kanicky, Viktor, Smarda, Jan, Spasojević, Ivan, Benes, Petr, "Anti-cancer effects of wedelolactone: interactions with copper and subcellular localization" in Metallomics, 10, no. 10 (2018):1524-1531,
https://doi.org/10.1039/c8mt00191j . .

TY  - JOUR
AU  - Bozic, Bojana
AU  - Korać Jačić, Jelena
AU  - Stanković, Dalibor M.
AU  - Stanić, Marina
AU  - Popovic-Bijelic, Ana
AU  - Bogdanović Pristov, Jelena
AU  - Spasojević, Ivan
AU  - Bajčetić, Milica
PY  - 2017
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1044
AB  - Toxic effects of unconjugated bilirubin (BR) in neonatal hyperbilirubinemia have been related to redox and/or coordinate interactions with Cu2+. However, the development and mechanisms of such interactions at physiological pH have not been resolved. This study shows that BR reduces Cu2+ to Cu1+ in 1:1 stoichiometry. Apparently, BR undergoes degradation, i.e. BR and Cu2+ do not form stable complexes. The binding of Cu2+ to inorganic phosphates, liposomal phosphate groups, or to chelating drug penicillamine, impedes redox interactions with BR. Cu1+ undergoes spontaneous oxidation by O-2 resulting in hydrogen peroxide accumulation and hydroxyl radical production. In relation to this, copper and BR induced synergistic oxidative/damaging effects on erythrocytes membrane, which were alleviated by penicillamine. The production of reactive oxygen species by BR and copper represents a plausible cause of BR toxic effects and cell damage in hyperbilirubinemia. Further examination of therapeutic potentials of copper chelators in the treatment of severe neonatal hyperbilirubinemia is needed.
PB  - Elsevier Ireland Ltd, Clare
T2  - Chemico-Biological Interactions
T1  - Mechanisms of redox interactions of bilirubin with copper and the effects of penicillamine
EP  - 134
SP  - 129
VL  - 278
DO  - 10.1016/j.cbi.2017.10.022
ER  - 

@article{
author = "Bozic, Bojana and Korać Jačić, Jelena and Stanković, Dalibor M. and Stanić, Marina and Popovic-Bijelic, Ana and Bogdanović Pristov, Jelena and Spasojević, Ivan and Bajčetić, Milica",
year = "2017",
abstract = "Toxic effects of unconjugated bilirubin (BR) in neonatal hyperbilirubinemia have been related to redox and/or coordinate interactions with Cu2+. However, the development and mechanisms of such interactions at physiological pH have not been resolved. This study shows that BR reduces Cu2+ to Cu1+ in 1:1 stoichiometry. Apparently, BR undergoes degradation, i.e. BR and Cu2+ do not form stable complexes. The binding of Cu2+ to inorganic phosphates, liposomal phosphate groups, or to chelating drug penicillamine, impedes redox interactions with BR. Cu1+ undergoes spontaneous oxidation by O-2 resulting in hydrogen peroxide accumulation and hydroxyl radical production. In relation to this, copper and BR induced synergistic oxidative/damaging effects on erythrocytes membrane, which were alleviated by penicillamine. The production of reactive oxygen species by BR and copper represents a plausible cause of BR toxic effects and cell damage in hyperbilirubinemia. Further examination of therapeutic potentials of copper chelators in the treatment of severe neonatal hyperbilirubinemia is needed.",
publisher = "Elsevier Ireland Ltd, Clare",
journal = "Chemico-Biological Interactions",
title = "Mechanisms of redox interactions of bilirubin with copper and the effects of penicillamine",
pages = "134-129",
volume = "278",
doi = "10.1016/j.cbi.2017.10.022"
}

Bozic, B., Korać Jačić, J., Stanković, D. M., Stanić, M., Popovic-Bijelic, A., Bogdanović Pristov, J., Spasojević, I.,& Bajčetić, M.. (2017). Mechanisms of redox interactions of bilirubin with copper and the effects of penicillamine. in Chemico-Biological Interactions
Elsevier Ireland Ltd, Clare., 278, 129-134.
https://doi.org/10.1016/j.cbi.2017.10.022

Bozic B, Korać Jačić J, Stanković DM, Stanić M, Popovic-Bijelic A, Bogdanović Pristov J, Spasojević I, Bajčetić M. Mechanisms of redox interactions of bilirubin with copper and the effects of penicillamine. in Chemico-Biological Interactions. 2017;278:129-134.
doi:10.1016/j.cbi.2017.10.022 .

Bozic, Bojana, Korać Jačić, Jelena, Stanković, Dalibor M., Stanić, Marina, Popovic-Bijelic, Ana, Bogdanović Pristov, Jelena, Spasojević, Ivan, Bajčetić, Milica, "Mechanisms of redox interactions of bilirubin with copper and the effects of penicillamine" in Chemico-Biological Interactions, 278 (2017):129-134,
https://doi.org/10.1016/j.cbi.2017.10.022 . .

TY  - JOUR
AU  - Morina, Filis
AU  - Takahama, Umeo
AU  - Mojović, Miloš
AU  - Popovic-Bijelic, Ana
AU  - Veljović-Jovanović, Sonja
PY  - 2016
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/939
AB  - Catechins are transformed into dinitrosocatechins (diNOcats) and then oxidized to the quinones by salivary nitrite under conditions simulating the stomach. This manuscript deals with formation of stable radicals in the NO group of diNOcat during nitrite-induced oxidation of (+)-catechin and diNOcat at pH 2. We postulated two mechanisms for the stable radical formation; one is nitrous acid-induced oxidation of diNOcat in the A-ring, and the other intermolecular charge transfer from the A-ring of diNOcat and/or diNOcat quinone to the quinone moiety of the B-ring of diNOcat quinone. In addition, an unstable phenoxyl radical, which might be transformed into quinone, was also produced, accompanying the formation of the stable radical on the NO group. Taking the above results into account, we mainly focus on the adverse effects of the radicals and quinone, which may be produced from (+)-catechin in the stomach under the conditions of high salivary nitrite concentrations.
PB  - Elsevier Sci Ltd, Oxford
T2  - Food Chemistry
T1  - Formation of stable radicals in catechin/nitrous acid systems: Participation of dinitrosocatechin
EP  - 1122
SP  - 1116
VL  - 194
DO  - 10.1016/j.foodchem.2015.08.081
ER  - 

@article{
author = "Morina, Filis and Takahama, Umeo and Mojović, Miloš and Popovic-Bijelic, Ana and Veljović-Jovanović, Sonja",
year = "2016",
abstract = "Catechins are transformed into dinitrosocatechins (diNOcats) and then oxidized to the quinones by salivary nitrite under conditions simulating the stomach. This manuscript deals with formation of stable radicals in the NO group of diNOcat during nitrite-induced oxidation of (+)-catechin and diNOcat at pH 2. We postulated two mechanisms for the stable radical formation; one is nitrous acid-induced oxidation of diNOcat in the A-ring, and the other intermolecular charge transfer from the A-ring of diNOcat and/or diNOcat quinone to the quinone moiety of the B-ring of diNOcat quinone. In addition, an unstable phenoxyl radical, which might be transformed into quinone, was also produced, accompanying the formation of the stable radical on the NO group. Taking the above results into account, we mainly focus on the adverse effects of the radicals and quinone, which may be produced from (+)-catechin in the stomach under the conditions of high salivary nitrite concentrations.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Food Chemistry",
title = "Formation of stable radicals in catechin/nitrous acid systems: Participation of dinitrosocatechin",
pages = "1122-1116",
volume = "194",
doi = "10.1016/j.foodchem.2015.08.081"
}

Morina, F., Takahama, U., Mojović, M., Popovic-Bijelic, A.,& Veljović-Jovanović, S.. (2016). Formation of stable radicals in catechin/nitrous acid systems: Participation of dinitrosocatechin. in Food Chemistry
Elsevier Sci Ltd, Oxford., 194, 1116-1122.
https://doi.org/10.1016/j.foodchem.2015.08.081

Morina F, Takahama U, Mojović M, Popovic-Bijelic A, Veljović-Jovanović S. Formation of stable radicals in catechin/nitrous acid systems: Participation of dinitrosocatechin. in Food Chemistry. 2016;194:1116-1122.
doi:10.1016/j.foodchem.2015.08.081 .

Morina, Filis, Takahama, Umeo, Mojović, Miloš, Popovic-Bijelic, Ana, Veljović-Jovanović, Sonja, "Formation of stable radicals in catechin/nitrous acid systems: Participation of dinitrosocatechin" in Food Chemistry, 194 (2016):1116-1122,
https://doi.org/10.1016/j.foodchem.2015.08.081 . .

TY  - JOUR
AU  - Milić Komić, Sonja
AU  - Bogdanović Pristov, Jelena
AU  - Popovic-Bijelic, Ana
AU  - Zakrzewska, Joanna
AU  - Stanić, Marina
AU  - Kalauzi, Aleksandar
AU  - Spasojević, Ivan
PY  - 2016
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/950
AB  - Iron-organic interactions are involved in a variety of environmental phenomena, including photo-redox reactions, iron cycling and bioavailability, as well as contaminant fate. In this study we examined UV-induced redox reactions of iron and indole in water. The presence of one indole in the irradiated system resulted in the presence of eight reduced ferric ions, not counting direct photolysis of Fe3+ complexes with OH-, which gives Fe2+ and hydroxyl radical (HO center dot) as products. The main mechanisms that contribute to indole-related Fe3+ reduction i.e. Fe2+ accumulation are: (i) HO center dot scavenging, which prevents oxidation of Fe2+ by HO center dot; (ii) oxidation of indole and its derivatives by excited ferric iron; (iii) reduction of ferric iron by excited indole (not present under UV-A). Hydrated electrons released by UV-B-excited indole play only a minor role in the reduction of iron. Indole-derived radicals emerged as byproducts of indole/iron photochemistry. H-1 NMR and low-T EPR spectroscopy showed that indole forms a weak low-symmetry complex with Fe3+. The strongest interactions between iron and pi-cloud in the indole ring are at positions 2, 3, and 7. The formation of complex promotes electron transfer from excited indole to Fe3+. Our findings are important for understanding the catalysis of photo-reduction of iron by heterocyclic aromatic pollutants, and for the development of protocols for indole processing in wastewaters.
PB  - Elsevier, Amsterdam
T2  - Applied Catalysis B-Environmental
T1  - Photo-redox reactions of indole and ferric iron in water
EP  - 180
SP  - 174
VL  - 185
DO  - 10.1016/j.apcatb.2015.12.018
ER  - 

@article{
author = "Milić Komić, Sonja and Bogdanović Pristov, Jelena and Popovic-Bijelic, Ana and Zakrzewska, Joanna and Stanić, Marina and Kalauzi, Aleksandar and Spasojević, Ivan",
year = "2016",
abstract = "Iron-organic interactions are involved in a variety of environmental phenomena, including photo-redox reactions, iron cycling and bioavailability, as well as contaminant fate. In this study we examined UV-induced redox reactions of iron and indole in water. The presence of one indole in the irradiated system resulted in the presence of eight reduced ferric ions, not counting direct photolysis of Fe3+ complexes with OH-, which gives Fe2+ and hydroxyl radical (HO center dot) as products. The main mechanisms that contribute to indole-related Fe3+ reduction i.e. Fe2+ accumulation are: (i) HO center dot scavenging, which prevents oxidation of Fe2+ by HO center dot; (ii) oxidation of indole and its derivatives by excited ferric iron; (iii) reduction of ferric iron by excited indole (not present under UV-A). Hydrated electrons released by UV-B-excited indole play only a minor role in the reduction of iron. Indole-derived radicals emerged as byproducts of indole/iron photochemistry. H-1 NMR and low-T EPR spectroscopy showed that indole forms a weak low-symmetry complex with Fe3+. The strongest interactions between iron and pi-cloud in the indole ring are at positions 2, 3, and 7. The formation of complex promotes electron transfer from excited indole to Fe3+. Our findings are important for understanding the catalysis of photo-reduction of iron by heterocyclic aromatic pollutants, and for the development of protocols for indole processing in wastewaters.",
publisher = "Elsevier, Amsterdam",
journal = "Applied Catalysis B-Environmental",
title = "Photo-redox reactions of indole and ferric iron in water",
pages = "180-174",
volume = "185",
doi = "10.1016/j.apcatb.2015.12.018"
}

Milić Komić, S., Bogdanović Pristov, J., Popovic-Bijelic, A., Zakrzewska, J., Stanić, M., Kalauzi, A.,& Spasojević, I.. (2016). Photo-redox reactions of indole and ferric iron in water. in Applied Catalysis B-Environmental
Elsevier, Amsterdam., 185, 174-180.
https://doi.org/10.1016/j.apcatb.2015.12.018

Milić Komić S, Bogdanović Pristov J, Popovic-Bijelic A, Zakrzewska J, Stanić M, Kalauzi A, Spasojević I. Photo-redox reactions of indole and ferric iron in water. in Applied Catalysis B-Environmental. 2016;185:174-180.
doi:10.1016/j.apcatb.2015.12.018 .

Milić Komić, Sonja, Bogdanović Pristov, Jelena, Popovic-Bijelic, Ana, Zakrzewska, Joanna, Stanić, Marina, Kalauzi, Aleksandar, Spasojević, Ivan, "Photo-redox reactions of indole and ferric iron in water" in Applied Catalysis B-Environmental, 185 (2016):174-180,
https://doi.org/10.1016/j.apcatb.2015.12.018 . .