Some methods such as free radical-scavenging assays might
provide information on how the antioxidant are fundamental in
preventing reactive radical species from reaching lipoproteins,
polyunsaturated fatty acids, DNA, amino acids, proteins and sugars
in biological and food systems. The relatively stable organic radical
(DPPH) has been widely used in the determination of antioxidant
activity of single compounds, as well as of different plant extracts.
Antioxidants can deactivate (scavenge) stable free DPPH radical by
two major mechanisms: by reduction via electron transfer or by
hydrogen atom transfer that may occur also in parallel, in addition,
steric accessibility is one of the major determinants of the reaction