NMR studies on the antiradical mechanism of phenolic compounds towards 2,2-diphenil-1-pycridrazyl radical
Conference Paper
Overview
Overview
abstract
Phenolic compounds are the most abundant c1ass of natural antioxidants. These
types of compounds are ubiquitous in fruits and vegetables and in plant-derived beverages,
such tea and wine, being important constituents of human diet. Recent studies have pointed
out particular interest on phenolic type compounds (e.g. flavonoids, catechins, cinnamic and benzoic acid derivatives) with respect not on1y to the organoleptic characteristics of
foodstuffs (e.g. flavour, bitterness, astringency) but also to their potential benefits in
deleterious oxidative radicalar processes related with human disease (e.g. cancer,
atherosc1erosis).l,2
The antioxidant activity of phenolic compounds could be related with their
antiradicalar activity and/or with the ability to act as metal ions chelators. Although there
is general agreement that catecholic compounds possess radical scavenging properties till
now its mechanism of action is not fully understood.
The. determination of antiradicalar potency of antioxidants is usually performed
using "Trap Assays" from which a screening of their scavenging activity towards different
radical species could be obtained. The DPPH method is a non-enzymatic assay widely used
for this purpose, in which the reactivity of the tested compounds towards a stable free
radicaI2,2-diphenyl-l-picrylhydrazyl (DPPHe
) is measured.3
Following our interest on the antioxidant behaviour of phenolic compounds4
,5 the
mechanism of the antiradicalar activity of ortho-dihydroxy cinnamic acids and
2-styry1chromone derivatives towards DPPHe was studied by NMR spectroscopy.
