A number of assays have been introduced for the measurement
of the total antioxidant activity of body fluids
[1– 6], food extracts [7–11], and pure compounds [7,12–
16]. Each method relates to the generation of a different
radical, acting through a variety of mechanisms and the
measurement of a range of end points at a fixed time
point or over a range (reviewed in refs 13 and 17). Two
types of approach have been taken, namely, the inhibition
assays in that the extent of the scavenging by hydrogen-
or electron-donation of a pre-formed free radical
is the marker of antioxidant activity, as well as assays
involving the presence of antioxidant system during the
generation of the radical.