scholarly journals Free Radical Mediated Oxidative Degradation of Carotenes and Xanthophylls

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1038 ◽  
Author(s):  
Raphael C. Mordi ◽  
Olabisi T. Ademosun ◽  
Christiana O. Ajanaku ◽  
Ifedolapo O. Olanrewaju ◽  
John C. Walton
Keyword(s):  
Excited State ◽  
Free Radical ◽  
Vitamin A ◽  
Molecular Oxygen ◽  
Oxidative Degradation ◽  
Chain Structure ◽  
Ring Structure ◽  
Peroxyl Radicals ◽  
Chemical Structures ◽  
Excited State Quenching

This article reviews the excited-state quenching, pro-vitamin A activity and anticarcinogenicity of carotenes and xanthophylls in relation to their chemical structures. Excited-state quenching improved with the length of the conjugated chain structure. Pro-vitamin A activity was dependent on the presence of at least one beta-ionyl ring structure. The effectiveness of carotenoids as antioxidants depended on their ability to trap peroxyl radicals with production of resonance-stabilized carotenyl radicals. The products identified from oxidations of carotenes and xanthophylls with molecular oxygen and other oxidizing agents are presented. The free radical-mediated mechanisms that have been proposed to account for the different classes of products are reviewed.

scholarly journals Overtone Vibrational Transition-Induced Lanthanide Excited-State Quenching in Yb3+/Er3+-Doped Upconversion Nanocrystals

ACS Nano ◽  
2018 ◽  
Vol 12 (11) ◽  
pp. 10572-10575 ◽  
Author(s):  
Bingru Huang ◽  
Jan Bergstrand ◽  
Sai Duan ◽  
Qiuqiang Zhan ◽  
Jerker Widengren ◽  
...  
Keyword(s):  
Excited State ◽  
Vibrational Transition ◽  
Upconversion Nanocrystals ◽  
Excited State Quenching

scholarly journals Reply to “Overtone Vibrational Transition-Induced Lanthanide Excited-State Quenching in Yb3+/Er3+-Doped Upconversion Nanocrystals”

ACS Nano ◽  
2018 ◽  
Vol 12 (11) ◽  
pp. 10576-10577 ◽  
Author(s):  
Freddy T. Rabouw ◽  
P. Tim Prins ◽  
Pedro Villanueva-Delgado ◽  
Marieke Castelijns ◽  
Robin G. Geitenbeek ◽  
...  
Keyword(s):  
Excited State ◽  
Vibrational Transition ◽  
Upconversion Nanocrystals ◽  
Excited State Quenching

Manganese(III)-based oxidative free-radical reaction of α-allyl-β-keto ester with molecular oxygen

1993 ◽  
Vol 34 (52) ◽  
pp. 8509-8512 ◽  
Author(s):  
Takashi Ohshima ◽  
Mikiko Sodeoka ◽  
Masakatsu Shibasaki
Keyword(s):  
Free Radical ◽  
Molecular Oxygen ◽  
Radical Reaction ◽  
Free Radical Reaction ◽  
Keto Ester

Excited state dynamics of the11BO2 free radical

1984 ◽  
Vol 104 (1) ◽  
pp. 97-99 ◽  
Author(s):  
Lu Cheng-zai ◽  
Michael A.A. Clyne ◽  
Ian P. Llewellyn
Keyword(s):  
Excited State ◽  
Free Radical ◽  
Excited State Dynamics
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