Document Detail

Topical delivery of retinyl ascorbate: 4. Comparative anti-oxidant activity towards DPPH.
MedLine Citation:
PMID:  16036324     Owner:  NLM     Status:  MEDLINE    
The free radical scavenging properties of retinyl ascorbate (RA-AsA) were determined by monitoring the decomposition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) as a function of time and in comparison with ascorbic acid (AsA), ascorbic acid palmitate (AsA-Pal), retinoic acid (RA), retinol (ROL) and retinol palmitate (Rol-Pal). The rate constant of RA-AsA (mean3+/-SD) was 4.9+/-0.3 M(-1) s(-1), and indicated greater potency as an antioxidant compared to the rest of the test compounds (AsA 3.4+/-0.4 M(-1) s(-1), AsA-Pal, 2.9+/-0.2 M(-1) s(-1), RA 1.4+/-0.3 M(-1) s(-1), ROL 1.3+/-0.1 M(-1) s(-1), Rol-Pal exhibited insignificant activity). The decomposition rate constant of DPPH, 5+/-0.6 x 10(-8) M(-1) s(-1), in ethanol and BHA, 154+/-3 M(-1) s(-1) were both used as control. The compound RA-2-carboxy-2-hydroxy-ethanoate was isolated by prep-TLC and was identified, by 13C and 1HNMR spectroscopy, as the major by-product from the reaction of RA-AsA with DPPH, which was also found to be potent antioxidant, 2.1+/-0.2 M(-1) s(-1). This suggests that oxidation of AsA moiety did not lead to the production of erythrulose species, which could cause deleterious modifications of cellular proteins.
Kasem Abdulmajed; Chris McGuigan; Charles M Heard
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Free radical research     Volume:  39     ISSN:  1071-5762     ISO Abbreviation:  Free Radic. Res.     Publication Date:  2005 May 
Date Detail:
Created Date:  2005-07-22     Completed Date:  2005-09-29     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  9423872     Medline TA:  Free Radic Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  491-8     Citation Subset:  IM    
Welsh School of Pharmacy, Cardiff University, Cardiff, CF10 3XF, UK.
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MeSH Terms
Administration, Topical
Ascorbic Acid / administration & dosage,  analogs & derivatives,  chemistry*
Biphenyl Compounds / chemistry*
Free Radical Scavengers / chemistry*
Hydrazines / chemistry*
Tretinoin / chemistry
Vitamin A / analogs & derivatives,  chemistry
Reg. No./Substance:
0/Biphenyl Compounds; 0/Free Radical Scavengers; 0/Hydrazines; 0/Picrates; 0/Retinoids; 0/retinyl ascorbate; 11103-57-4/Vitamin A; 1898-66-4/2,2-diphenyl-1-picrylhydrazyl; 302-79-4/Tretinoin; 50-81-7/Ascorbic Acid; 79-81-2/retinol palmitate

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