Kinetics of the lipoperoxyl radical-scavenging activity of indicaxanthin in solution and unilamellar liposomes.
Free Radic Res
; 41(2): 226-33, 2007 Feb.
Article
em En
| MEDLINE
| ID: mdl-17364949
ABSTRACT
The reaction of the phytochemical indicaxanthin with lipoperoxyl radicals generated in methyl linoleate methanol solution by 2,2'-azobis(2,4-dimethylvaleronitrile), and in aqueous soybean phosphatidylcholine unilamellar liposomes by 2,2'-azobis(2-amidinopropane)hydrochloride, was studied. The molecule acts as a chain-terminating lipoperoxyl radical scavenger in solution, with a calculated inhibition constant of 3.63 x 10(5) M(-1) s(-1), and a stoichiometric factor approaching 2. Indicaxanthin incorporated in liposomes prevented lipid oxidation, inducing clear-cut lag periods and decrease of the propagation rate. Both effects were concentration-dependent, but not linearly related to the phytochemical concentration. The consumption of indicaxanthin during liposome oxidation was remarkably delayed, the lower the concentration the longer the time-interval during which it remained in its native state. Indicaxanthin and alpha-tocopherol, simultaneously incorporated in liposomes, exhibited cooperative antioxidant effects and reciprocal protective interactions. The extent of synergism decreased at the increase of the ratio (indicaxanthin)/(alpha-tocopherol). A potential antioxidant mechanism of indicaxanthin is discussed in the context of the chemistry of the molecule, and of the possible reactivity of a short-lived intermediate.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Piridinas
/
Sequestradores de Radicais Livres
/
Betaxantinas
/
Peróxidos Lipídicos
/
Lipossomos
/
Antioxidantes
Idioma:
En
Revista:
Free Radic Res
Assunto da revista:
BIOQUIMICA
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Itália