Singlet Oxygen Reactions with Flavonoids. A Theoretical – Experimental Study
Author
dc.contributor.author
Morales, Javier
Author
dc.contributor.author
Günther Sapunar, Germán
es_CL
Author
dc.contributor.author
Zanocco Loyola, Antonio
es_CL
Author
dc.contributor.author
Lemp Miranda, Else
Admission date
dc.date.accessioned
2014-01-07T19:22:34Z
Available date
dc.date.available
2014-01-07T19:22:34Z
Publication date
dc.date.issued
2007-07
Cita de ítem
dc.identifier.citation
PLoS ONE 7(7): e40548. 2007
en_US
Identifier
dc.identifier.other
doi:10.1371/journal.pone.0040548
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/121704
General note
dc.description
Artículo de publicación ISI
en_US
Abstract
dc.description.abstract
Detection of singlet oxygen emission, lmax = 1270 nm, following laser excitation and steady-state methods were employed
to measure the total reaction rate constant, kT, and the reactive reaction rate constant, kr, for the reaction between singlet
oxygen and several flavonoids. Values of kT determined in deuterated water, ranging from 2.46107 M21s21 to
13.46107 M21s21, for rutin and morin, respectively, and the values measured for kr, ranging from 2.86105 M21s21 to
65.76105 M21s21 for kaempferol and morin, respectively, being epicatechin and catechin chemically unreactive. These
results indicate that all the studied flavonoids are good quenchers of singlet oxygen and could be valuable antioxidants in
systems under oxidative stress, in particular if a flavonoid-rich diet was previously consumed. Analysis of the dependence of
rate constant values with molecular structure in terms of global descriptors and condensed Fukui functions, resulting from
electronic structure calculations, supports the formation of a charge transfer exciplex in all studied reactions. The fraction of
exciplex giving reaction products evolves through a hydroperoxide and/or an endoperoxide intermediate produced by
singlet oxygen attack on the double bond of the ring C of the flavonoid.