Post-Trapping Derivatization of Radical-Derived EPR-Silent Adducts: Application to Free Radical Detection by HPLC/UV in Chemical, Biochemical, and Biological Systems and Comparison with EPR Spectroscopy

2012 ◽  
Vol 84 (15) ◽  
pp. 6739-6746 ◽  
Author(s):  
Karim Michail ◽  
Arno G. Siraki
Keyword(s):  
Free Radical ◽  
Epr Spectroscopy ◽  
Biological Systems ◽  
Radical Detection

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

2015 ◽  
Vol 98 (4) ◽  
pp. 866-870 ◽  
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).

scholarly journals Free radical chemistry in biological systems

2000 ◽  
Vol 33 (2) ◽  
Author(s):  
LAURA B VALDEZ ◽  
SILVIA LORES ARNAIZ ◽  
JUANITA BUSTAMANTE ◽  
SILVIA ALVAREZ ◽  
LIDIA E COSTA ◽  
...  
Keyword(s):  
Free Radical ◽  
Biological Systems ◽  
Radical Chemistry ◽  
Free Radical Chemistry

scholarly journals The Electronic Structure of the Cys-Tyr•Free Radical in Galactose Oxidase Determined by EPR Spectroscopy†

Biochemistry ◽  
2008 ◽  
Vol 47 (25) ◽  
pp. 6637-6649 ◽  
Author(s):  
Yuk-Ki Lee ◽  
Mei M. Whittaker ◽  
James W. Whittaker
Keyword(s):  
Electronic Structure ◽  
Free Radical ◽  
Epr Spectroscopy ◽  
Galactose Oxidase
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