Short-lived Phenoxyl Radicals Formed from Green-Tea Polyphenols and Highly Reactive Oxygen Species: An Investigation by Time-Resolved EPR Spectroscopy

2014 ◽  
Vol 53 (48) ◽  
pp. 13288-13292 ◽  
Author(s):  
Dmytro Neshchadin ◽  
Stephen N. Batchelor ◽  
Itzhak Bilkis ◽  
Georg Gescheidt
Keyword(s):  
Reactive Oxygen Species ◽  
Green Tea ◽  
Epr Spectroscopy ◽  
Reactive Oxygen ◽  
Tea Polyphenols ◽  
Green Tea Polyphenols ◽  
Oxygen Species ◽  
Phenoxyl Radicals ◽  
Time Resolved

scholarly journals Green tea polyphenols potentiate the action of nerve growth factor to induce neuritogenesis: Possible role of reactive oxygen species

2010 ◽  
Vol 88 (16) ◽  
pp. 3644-3655 ◽  
Author(s):  
Usha Gundimeda ◽  
Thomas H. McNeill ◽  
Jason E. Schiffman ◽  
David R. Hinton ◽  
Rayudu Gopalakrishna
Keyword(s):  
Reactive Oxygen Species ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Green Tea ◽  
Reactive Oxygen ◽  
Tea Polyphenols ◽  
Green Tea Polyphenols ◽  
Oxygen Species ◽  
Nerve Growth

Photoassisted Production of O2-• and H2 in Aqueous Medium Stimulated by Polythiophene in ZSM-5 Zeolite Channels

1999 ◽  
Vol 64 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Gabriel Čík ◽  
František Šeršeň ◽  
Alena Bumbálová
Keyword(s):  
Reactive Oxygen Species ◽  
Ion Exchange ◽  
Visible Light ◽  
Aqueous Medium ◽  
Exchange Reaction ◽  
Epr Spectroscopy ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Water Reduction ◽  
Ion Exchange Reaction

The formation of reactive oxygen species due to irradiation by a visible light of the polythiophene deposited in ZSM-5 zeolite channels in aqueous medium has been studied. Polymerization of thiophene was carried out in zeolite channels after the ion-exchange reaction of Na+ for Fe3+. By means of EPR spectroscopy, the temporarily generated 1O2 in irradiated aqueous medium was proved. The formation of O2-• was confirmed by the reduction of Fe3+-cytochrome c. Irradiation led to the water reduction to hydrogen.

scholarly journals An EPR characterisation of stable and transient reactive oxygen species formed under radiative and non-radiative conditions

2019 ◽  
Vol 45 (12) ◽  
pp. 5763-5779 ◽  
Author(s):  
E. Richards ◽  
D. M. Murphy ◽  
M. Che
Keyword(s):  
Reactive Oxygen Species ◽  
Epr Spectroscopy ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Intermediate Species ◽  
Paramagnetic Resonance ◽  
General Terms ◽  
Electron Paramagnetic ◽  
Ideal Method ◽  
The Ideal

Abstract Electron paramagnetic resonance (EPR) spectroscopy is the ideal method of choice when detecting and studying the wide variety of paramagnetic oxygen-centred radicals. For simple diatomic radicals, such as the superoxide (O2−) or peroxy $$ ({\text{ROO}}^{\bullet})$$(ROO∙) species, the CW EPR profile (in particular the g-values) of these species can appear similar and indeed indistinguishable in some cases. Experiments using 17O-enriched oxygen, revealing a rich 17O hyperfine pattern, are therefore essential to distinguish between the two species. However, in many cases, particularly involving TiO2 photocatalysis, the peroxy-type $$ ({\text{ROO}}^{\bullet})$$(ROO∙) radicals or other intermediate species such as the [O2−…organic]-type adducts can be transient in nature and once again can produce similar g-values. In general terms, these reactive oxygen species (ROS) are formed and detected at low-temperature conditions. Hence, the application of EPR spectroscopy to studies of surface-stabilised oxygen-centred radicals must be performed under carefully selected conditions in order to confidently distinguish between the differing types of diatomic radicals, such as O2−, $$ {\text{ROO}}^{\bullet}$$ROO∙ or [O2−…organic].

Green Tea Component, Catechin, Induces Apoptosis of Human Malignant B Cells via Production of Reactive Oxygen Species

2005 ◽  
Vol 11 (16) ◽  
pp. 6040-6049 ◽  
Author(s):  
Tomonori Nakazato ◽  
Keisuke Ito ◽  
Yasuo Ikeda ◽  
Masahiro Kizaki
Keyword(s):  
Reactive Oxygen Species ◽  
B Cells ◽  
Green Tea ◽  
Reactive Oxygen ◽  
Oxygen Species
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