Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma

We evaluated the interaction between ascorbic acid (AA) and (+)-catechin (CTCH) in potassium phosphate solution, pH 7.4 (PPS) and in human plasma. In both systems, the oxidation was started by adding 2,2-azobis-(2-amidinopropane) clorhidrate (AAPH). The concentrations of AA and CTCH were determined...

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Autores principales:	LOTITO,SILVINA B, FRAGA,CESAR G
Lenguaje:	English
Publicado:	Sociedad de Biología de Chile 2000
Materias:	catechins antioxidants free radicals procyanidins
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200015
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spelling	oai:scielo:S0716-976020000002000152010-02-11Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasmaLOTITO,SILVINA BFRAGA,CESAR G catechins antioxidants free radicals procyanidins We evaluated the interaction between ascorbic acid (AA) and (+)-catechin (CTCH) in potassium phosphate solution, pH 7.4 (PPS) and in human plasma. In both systems, the oxidation was started by adding 2,2-azobis-(2-amidinopropane) clorhidrate (AAPH). The concentrations of AA and CTCH were determined by HPLC using electrochemical detection. In PPS, CTCH was oxidized by AAPH (50 muM), in either the absence or presence of different initial concentrations of AA (25-200 muM). In the presence of AA, CTCH depletion was delayed, an effect that was dependent upon the initial concentration of AA. When 100 muM AA was added after the oxidation had begun, CTCH depletion was arrested for 30 min. The kinetics of AA oxidation by AAPH was also characterized in PPS. AA (100 muM) was completely consumed after 60 min of reaction at 37 muC, in both the absence and presence of 100 mM CTCH. When human plasma was incubated with 50 mM AAPH in the absence of added CTCH, AA was completely consumed after 45-60 min. CTCH did not prevent AA depletion in human plasma at the concentrations tested (10, 50 100 muM). The results point out that AA is able to protect other aqueous soluble antioxidants, e.g.: CTCHinfo:eu-repo/semantics/openAccessSociedad de Biología de ChileBiological Research v.33 n.2 20002000-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200015en10.4067/S0716-97602000000200015
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	catechins antioxidants free radicals procyanidins
spellingShingle	catechins antioxidants free radicals procyanidins LOTITO,SILVINA B FRAGA,CESAR G Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma
description	We evaluated the interaction between ascorbic acid (AA) and (+)-catechin (CTCH) in potassium phosphate solution, pH 7.4 (PPS) and in human plasma. In both systems, the oxidation was started by adding 2,2-azobis-(2-amidinopropane) clorhidrate (AAPH). The concentrations of AA and CTCH were determined by HPLC using electrochemical detection. In PPS, CTCH was oxidized by AAPH (50 muM), in either the absence or presence of different initial concentrations of AA (25-200 muM). In the presence of AA, CTCH depletion was delayed, an effect that was dependent upon the initial concentration of AA. When 100 muM AA was added after the oxidation had begun, CTCH depletion was arrested for 30 min. The kinetics of AA oxidation by AAPH was also characterized in PPS. AA (100 muM) was completely consumed after 60 min of reaction at 37 muC, in both the absence and presence of 100 mM CTCH. When human plasma was incubated with 50 mM AAPH in the absence of added CTCH, AA was completely consumed after 45-60 min. CTCH did not prevent AA depletion in human plasma at the concentrations tested (10, 50 100 muM). The results point out that AA is able to protect other aqueous soluble antioxidants, e.g.: CTCH
author	LOTITO,SILVINA B FRAGA,CESAR G
author_facet	LOTITO,SILVINA B FRAGA,CESAR G
author_sort	LOTITO,SILVINA B
title	Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma
title_short	Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma
title_full	Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma
title_fullStr	Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma
title_full_unstemmed	Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma
title_sort	ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma
publisher	Sociedad de Biología de Chile
publishDate	2000
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200015
work_keys_str_mv	AT lotitosilvinab ascorbateprotectscatechinfromoxidationbothinapurechemicalsystemandhumanplasma AT fragacesarg ascorbateprotectscatechinfromoxidationbothinapurechemicalsystemandhumanplasma
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Ascorbate protects (+)-catechin from oxidation both in a pure chemical system and human plasma

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