The antioxidant activity of putative antioxidants have been
attributed to various mechanisms, main of which are prevention of
chain initiation, binding of transition metal ion catalysts, decomposition
of peroxides, prevention of continued hydrogen abstraction,
reductive capacity and radical scavenging (El-Agamey et al., 2004;
Oktay, Gülc¸ in, & Küfrevio˘glu, 2003). Numerous antioxidant methods
and modifications have been proposed to evaluate antioxidant
activity and to explain how antioxidants work. Of these, reducing
power, DPPH assay, active oxygen species such as H2O2, O2
•− and
OH• quenching assays are most commonly used for the evaluation
of antioxidant activities of functional materials