In this study, the tests used allowed two properties of these compounds to be assessed (18, 19):
direct antioxidant activity, as regards induction of lipid peroxidation on microsome and LDL
tests, and the direct scavenging effect on a stable free radical, DPPH.
To be considered as an antioxidant, a polyphenol must satisfy two basic conditions: first, when
present at a low concentration relative to the substrate to be oxidized, it can delay or prevent
autooxidation or free radical-mediated oxidation; secondly, the resulting free radical formed after
scavenging must be stable upon further oxidation (20).