Document Detail


Kinetics of parallel electron transfer from beta-carotene to phenoxyl radical and adduct formation between phenoxyl radical and beta-carotene.
MedLine Citation:
PMID:  8951424     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Phenoxyl radicals generated by laser flash photolysis were found to react with beta-carotene with concomitant beta-carotene bleaching in two parallel reactions with similar rates: (i) formation of a beta-carotene adduct with a (pseudo) first order rate constant of 1-1.5 x 10(4) s-1 with absorption maximum around 800 nm, and (ii) formation of a beta-carotene radical cation with a (pseudo) first order rate constant of 2-3 x 10(4) s-1 with absorption maximum around 920 nm. Both beta-carotene radicals decay on a similar time scale and have virtually disappeared after 100 ms, the beta-carotene adduct by a second order process. Oxygen had no effect on beta-carotene bleaching or radical formation and decay. The reduction of phenoxyl radicals by beta-carotene may prove important for an understanding of how beta-carotene acts as an antioxidant.
Authors:
A Mortensen; L H Skibsted
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Free radical research     Volume:  25     ISSN:  1071-5762     ISO Abbreviation:  Free Radic. Res.     Publication Date:  1996 Dec 
Date Detail:
Created Date:  1997-02-28     Completed Date:  1997-02-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9423872     Medline TA:  Free Radic Res     Country:  SWITZERLAND    
Other Details:
Languages:  eng     Pagination:  515-23     Citation Subset:  IM    
Affiliation:
Department of Dairy and Food Science, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
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MeSH Terms
Descriptor/Qualifier:
Electron Transport
Free Radicals
Kinetics
Phenols / chemistry*
Photolysis
Spin Trapping
beta Carotene / chemistry*
Chemical
Reg. No./Substance:
0/Free Radicals; 0/Phenols; 3229-70-7/phenoxy radical; 7235-40-7/beta Carotene

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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