Although both Oy and H O are potentially cytotoxic, most of the oxidative
2 2 2
damage in biological systems is caused by the •OH radical, which is generated by
the reaction between Oy and H O in the presence of transition metal ions w30x. In
2 2 2
fact, the •OH radical can react with a number of target molecules including proteins,
membrane lipids and DNA. In the present study, the antiperoxidative capacity of
propolis extract (with and without CAPE) and its active components, on linoleic
acid oxidation, induced by •OH radicals, generated from UV-photolysis of H O ,
2 2
was also evaluated. All natural compounds determined an inhibition of linoleic acid
oxidation, but at higher concentrations since the method employed for evaluating
the antioxidant capacity generated very high amounts of free radicals. Propolis
extract with CAPE showed a more potent capacity to reduce TBARS formation
than propolis extract without CAPE. Also CAPE (200, 400 and 800 mM) exhibits
a protective effect against peroxidation, compared to control and showed a more
potent hydroxyl radicals scavenging capacity than galangin.
In conclusion, our study provides evidence that propolis extract exhibits interesting
antioxidant properties, higher than propolis deprived of CAPE. This would suggest
a significant contribution of this phenolic compound to the antioxidant activity of
propolis.