In vitro antioxidant properties of golden grass (Syngonanthus nitens) by electron paramagnetic resonance

The number of mononitrosyl iron complexes with diethyldithiocarbamate, formed in the liver of mice in vivo and in vitro after intraperitoneal injection of binuclear dinitrosyl iron complexes with N-acetyl-L-cysteine or glutathione, S-nitrosoglutathione, sodium nitrite or the vasodilating drug Isoket® was assessed by electron paramagnetic resonance (EPR). The number of the said complexes, in contrast to the complexes, formed after nitrite or Isoket administration, the level of which sharply increased after treatment of liver preparations with a strong reducing agent - dithionite, did not change in the presence of dithionite. It was concluded that, in the first case, EPR-detectable mononitrosyl iron complexes with diethyldithiocarbamate in the absence and presence of dithionite appeared as a result of the reaction of NO formed from nitrite with Fe2+-dieth- yldithiocarbamate and Fe3+-diethyldithiocarbamate complexes, respectively. In the second case, mononitrosyl iron complexes with diethyldithiocarbamate appeared as a result of the transition of iron-mononitosyl fragments from ready-made iron-dinitrosyl groups of binuclear dinitrosyl complexes, which is three to four times higher than the content of the mononuclear form of these complexes in the tissue...

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Investigation of Antioxidant Activity of Pomegranate Juices by Means of Electron Paramagnetic Resonance and UV-Vis Spectroscopy

Journal of AOAC International ◽

10.5740/jaoacint.sge4-kozik ◽

2015 ◽

Vol 98 (4) ◽

pp. 866-870 ◽

Cited By ~ 6

Author(s):

Violetta Kozik ◽

Krystyna Jarzembek ◽

Agnieszka Jędrzejowska ◽

Andrzej Bąk ◽

Justyna Polak ◽

...

Keyword(s):

Electron Paramagnetic Resonance ◽

Free Radical ◽

Epr Spectroscopy ◽

Antioxidant Properties ◽

Free Radical Scavenger ◽

Pomegranate Juice ◽

Radical Scavenger ◽

Paramagnetic Resonance ◽

Vis Spectroscopy ◽

Electron Paramagnetic

Abstract Pomegranate fruit (Punica granatum L.) is a source of numerous phenolic compounds, and it contains flavonoids such as anthocyanins, anthocyanidins, cyanidins, catechins and other complexes of flavonoids, ellagitannins, and hydrolyzed tannins. Pomegranate juice shows antioxidant, antiproliferative, and anti-atherosclerotic properties. The antioxidant capacity (TEAC) of the pomegranate juices was measured using electron paramagnetic resonance (EPR) spectroscopy and 1,1-diphenyl-2-picrylhydrazyl (DPPH•) as a source of free radicals, and the total phenolic (TP) content was measured using UV-Vis spectroscopy. All the examined pomegranate juices exhibited relatively high antioxidant properties. The TEAC values determined by means of EPR spectroscopy using Trolox (TE) as a free radical scavenger were in the range of 463.12 to 1911.91 μmol TE/100 mL juice. The TP content measured by the Folin-Ciocalteu method, using gallic acid (GA) as a free radical scavenger, widely varied in the investigated pomegranate juice samples and ranged from 1673.62 to 5263.87 mg GA/1 L juice. The strongest antioxidant properties were observed with the fresh pomegranate juices obtained from the fruits originating from Israel, Lebanon, and Azerbaijan. Correlation analysis of numerical data obtained by means of EPR spectroscopy (TEAC) and UV-Vis spectroscopy (TP) gave correlation coefficient (r) = 0.90 and determination coefficient (r2) = 0.81 (P <0.05).

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Fluorescent Copper(II) Bis(thiosemicarbazonates): Synthesis, Structures, Electron Paramagnetic Resonance, Radiolabeling, In Vitro Cytotoxicity and Confocal Fluorescence Microscopy Studies

Chemistry - An Asian Journal ◽

10.1002/asia.200900446 ◽

2010 ◽

Vol 5 (3) ◽

pp. 506-519 ◽

Cited By ~ 43

Author(s):

Sofia I. Pascu ◽

Philip A. Waghorn ◽

Brett W. C. Kennedy ◽

Rory L. Arrowsmith ◽

Simon R. Bayly ◽

...

Keyword(s):

Electron Paramagnetic Resonance ◽

Fluorescence Microscopy ◽

In Vitro Cytotoxicity ◽

Confocal Fluorescence Microscopy ◽

Paramagnetic Resonance ◽

Confocal Fluorescence ◽

Electron Paramagnetic

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Role of leptin as antioxidant in obstructive sleep apnea: an in vitro study using electron paramagnetic resonance method

Sleep And Breathing ◽

10.1007/s11325-012-0656-8 ◽

2012 ◽

Vol 17 (1) ◽

pp. 105-110 ◽

Cited By ~ 5

Author(s):

Madalina Macrea ◽

Thomas Martin ◽

Leon Zagrean ◽

Zhenquan Jia ◽

Hara Misra

Keyword(s):

Electron Paramagnetic Resonance ◽

Obstructive Sleep Apnea ◽

In Vitro Study ◽

Resonance Method ◽

Paramagnetic Resonance ◽

Electron Paramagnetic Resonance Method ◽

Obstructive Sleep ◽

Electron Paramagnetic

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[FeFe]-Hydrogenase Maturation: H-Cluster Assembly Intermediates Tracked by Electron Paramagnetic Resonance, Infrared, and X-Ray Absorption Spectroscopy

10.26434/chemrxiv.12168303.v1 ◽

2020 ◽

Author(s):

Brigitta Németh ◽

Moritz Senger ◽

Holly J. Redman ◽

Pierre Ceccaldi ◽

Joan Broderick ◽

...

Keyword(s):

Electron Paramagnetic Resonance ◽

Absorption Spectroscopy ◽

Cluster Assembly ◽

Paramagnetic Resonance ◽

X Ray ◽

Hydrogenase Maturation ◽

Catalytically Active ◽

X Ray Absorption ◽

Electron Paramagnetic

[FeFe]-hydrogenase enzymes employ a unique organometallic cofactor for efficient and reversible hydrogen conversion. This so-called H-cluster consists of a [4Fe-4S] cubane cysteine-linked to a diiron complex coordinated by carbon monoxide and cyanide ligands and an azadithiolate ligand (adt = NH(CH2S)2). [FeFe]-hydrogenase apo-protein binding only the [4Fe-4S] sub-complex can be fully activated in vitro by the addition of a synthetic diiron site precursor complex ([2Fe]adt,). Elucidation of the mechanism of cofactor assembly will aid in the design of improved hydrogen processing synthetic catalysts. We combined in situ electron paramagnetic resonance, Fourier-transform infrared, and X-ray absorption spectroscopy to characterize intermediates of H-cluster assembly as initiated by mixing of the apo-protein (HydA1) from the green alga Chlamydomonas reinhardtii with [2Fe]adt. The three methods consistently show rapid formation of a complete H-cluster in the oxidized, CO-inhibited state (Hox-CO) already within seconds after the mixing. Moreover, FTIR spectroscopy support a model in which Hox-CO formation is preceded by a short-lived Hred´-CO like intermediate. Accumulation of Hox-CO was followed by CO release resulting in the slower conversion to the catalytically active state (Hox) as well as formation of reduced states of the H-cluster.

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