Antioxidant Mechanisms of Polyphenolic Caffeic Acid Oligomers, Constituents of Salvia officinalis

Caffeic acid, rosmarinic acid and oligomers of caffeic acid with multiple catechol groups are all constituents of Salvia officinalis. Their antioxidant potential was investigated with regard to their radical scavenging activity and the stability and structure of the intermediate radicals. Pulse-radi...

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Autores principales:	BORS,WOLF, CHRISTA,MICHEL, STETTMAIER,KURT, YINRONG,LU, L. YEAP,FOO
Lenguaje:	English
Publicado:	Sociedad de Biología de Chile 2004
Materias:	Caffeic acid oligomer catechol semiquinone electron paramagnetic resonance hydroxyl radical kinetic modeling pulse radiolysis Salvia officinalis
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000200017
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spelling	oai:scielo:S0716-976020040002000172005-01-06Antioxidant Mechanisms of Polyphenolic Caffeic Acid Oligomers, Constituents of Salvia officinalisBORS,WOLFCHRISTA,MICHELSTETTMAIER,KURTYINRONG,LUL. YEAP,FOO Caffeic acid oligomer catechol semiquinone electron paramagnetic resonance hydroxyl radical kinetic modeling pulse radiolysis Salvia officinalis Caffeic acid, rosmarinic acid and oligomers of caffeic acid with multiple catechol groups are all constituents of Salvia officinalis. Their antioxidant potential was investigated with regard to their radical scavenging activity and the stability and structure of the intermediate radicals. Pulse-radiolytic studies revealed very high rate constants with hydroxyl radicals. Evidence from kinetic modeling calculations suggested an unusual complex behavior due to the presence of both O4- and O3-semiquinones and formation and decay of a hydroxyl radical adduct at the vinyl side chain. The radical structures observed by EPR spectroscopy after autoxidation in slightly alkaline solutions were only partially identified due to their instability and generally represented dissociated O4-semiquinones. Hybrid density-functional calculations of the potential radical structures showed distinct differences between the resonance stabilization of the O4- and O3-semiquinones of caffeic and dihydrocaffeic acids, reflected also in the considerably faster decay of the O3-semiquinone observed by pulse radiolysis. No evidence was found for dimerization reactions via Cb radicals typical for lignin biosynthesisinfo:eu-repo/semantics/openAccessSociedad de Biología de ChileBiological Research v.37 n.2 20042004-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000200017en10.4067/S0716-97602004000200017
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Caffeic acid oligomer catechol semiquinone electron paramagnetic resonance hydroxyl radical kinetic modeling pulse radiolysis Salvia officinalis
spellingShingle	Caffeic acid oligomer catechol semiquinone electron paramagnetic resonance hydroxyl radical kinetic modeling pulse radiolysis Salvia officinalis BORS,WOLF CHRISTA,MICHEL STETTMAIER,KURT YINRONG,LU L. YEAP,FOO Antioxidant Mechanisms of Polyphenolic Caffeic Acid Oligomers, Constituents of Salvia officinalis
description	Caffeic acid, rosmarinic acid and oligomers of caffeic acid with multiple catechol groups are all constituents of Salvia officinalis. Their antioxidant potential was investigated with regard to their radical scavenging activity and the stability and structure of the intermediate radicals. Pulse-radiolytic studies revealed very high rate constants with hydroxyl radicals. Evidence from kinetic modeling calculations suggested an unusual complex behavior due to the presence of both O4- and O3-semiquinones and formation and decay of a hydroxyl radical adduct at the vinyl side chain. The radical structures observed by EPR spectroscopy after autoxidation in slightly alkaline solutions were only partially identified due to their instability and generally represented dissociated O4-semiquinones. Hybrid density-functional calculations of the potential radical structures showed distinct differences between the resonance stabilization of the O4- and O3-semiquinones of caffeic and dihydrocaffeic acids, reflected also in the considerably faster decay of the O3-semiquinone observed by pulse radiolysis. No evidence was found for dimerization reactions via Cb radicals typical for lignin biosynthesis
author	BORS,WOLF CHRISTA,MICHEL STETTMAIER,KURT YINRONG,LU L. YEAP,FOO
author_facet	BORS,WOLF CHRISTA,MICHEL STETTMAIER,KURT YINRONG,LU L. YEAP,FOO
author_sort	BORS,WOLF
title	Antioxidant Mechanisms of Polyphenolic Caffeic Acid Oligomers, Constituents of Salvia officinalis
title_short	Antioxidant Mechanisms of Polyphenolic Caffeic Acid Oligomers, Constituents of Salvia officinalis
title_full	Antioxidant Mechanisms of Polyphenolic Caffeic Acid Oligomers, Constituents of Salvia officinalis
title_fullStr	Antioxidant Mechanisms of Polyphenolic Caffeic Acid Oligomers, Constituents of Salvia officinalis
title_full_unstemmed	Antioxidant Mechanisms of Polyphenolic Caffeic Acid Oligomers, Constituents of Salvia officinalis
title_sort	antioxidant mechanisms of polyphenolic caffeic acid oligomers, constituents of salvia officinalis
publisher	Sociedad de Biología de Chile
publishDate	2004
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000200017
work_keys_str_mv	AT borswolf antioxidantmechanismsofpolyphenoliccaffeicacidoligomersconstituentsofsalviaofficinalis AT christamichel antioxidantmechanismsofpolyphenoliccaffeicacidoligomersconstituentsofsalviaofficinalis AT stettmaierkurt antioxidantmechanismsofpolyphenoliccaffeicacidoligomersconstituentsofsalviaofficinalis AT yinronglu antioxidantmechanismsofpolyphenoliccaffeicacidoligomersconstituentsofsalviaofficinalis AT lyeapfoo antioxidantmechanismsofpolyphenoliccaffeicacidoligomersconstituentsofsalviaofficinalis
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Antioxidant Mechanisms of Polyphenolic Caffeic Acid Oligomers, Constituents of Salvia officinalis

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