Kinetic Studies on Stilbazulenyl-bis-nitrone (STAZN), a Nonphenolic Chain-Breaking Antioxidant in Solution, Micelles, and Lipid Membranes

Download
  1. Get@NRC: Kinetic Studies on Stilbazulenyl-bis-nitrone (STAZN), a Nonphenolic Chain-Breaking Antioxidant in Solution, Micelles, and Lipid Membranes (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1021/jo030390iS0022-3263(03)00390-6
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleJournal Of Organic Chemistry
ISSN00223263
Volume69
Issue9
Pages29292936; # of pages: 8
AbstractThe rate constants, kinh, for reaction of stilbazulenyl-bis-nitrone (STAZN, 1) with peroxyl radicals and the number of radicals trapped, n, are compared with those of phenolic antioxidants 2,2,5,7,8-pentamethyl-6-hydroxychroman (PMHC, 4a), 2,5,7,8-tetramethyl-6-hydroxychroman-2-carboxylic acid (Trolox, 4b), and 2,6-di-tert-butyl-4-methoxyphenol (DBHA, 5). The behavior of STAZN depended markedly on the media and type of initiator used, water-soluble or lipid-soluble. In styrene/chlorobenzene and initiation by azo-bis(isobutyronitrile) (AIBN), kinh (STAZN) = 0.64 kinh (5) = 0.02kinh (4a). On addition of methanol, the kinh of STAZN increased 6-fold to be four times that of 5 while that of 4a decreased 6-fold. In aqueous SDS-micelles containing methyl linoleate and initiation with water-soluble azo-bis(amidinopropane)2HCl, ABAP, the relative kinh values were 1 4b > 5. In dilinoleoylphosphatidyl choline (DLPC) bilayers and initiation with lipid-soluble azo-bis-2,4(dimethylvaleronitrile) (DMVN), the kinh order was 5 > 4b > 1. During initiation with ABAP in micelles and bilayers, the calculated values of kinh for STAZN changed during the induction period. The experimental results are interpreted in terms of the conformation of STAZN, which is transoid in homogeneous solution but cisoid in aqueous dispersions of lipids. In such dispersions, the STAZN lies at the lipid-water interface where it traps water-soluble peroxyl radicals by a single electron-transfer mechanism. The cisoid conformation at lipid-water interfaces is supported by theoretical calculations.
Publication date
AffiliationNational Research Council Canada; National Institute for Nanotechnology; NRC Steacie Institute for Molecular Sciences
Peer reviewedNo
Identifier10008226
NPARC number12332816
Export citationExport as RIS
Report a correctionReport a correction
Record identifier8f6686db-6e31-46a4-9d22-e26b9e6159a3
Record created2009-09-10
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)