The TEAC (Trolox equivalent antioxidant capacity) assay was
used to determine the free radical scavenging capacity using the
ABTS radical cation (Re et al., 1999). ABTS radical cation was
prepared by reacting 7 mM ABTS stock solution with 2.45 mM
potassium persulfate in a volume ratio of 1:1. The mixture was
incubated in the dark for 16 h at room temperature before use.
100 L of the diluted sample was mixed with 3.8 mL ABTS working
solution. After incubating the reaction mixture for 6 min at
room temperature, absorbance was measured at 734 nm, and the
percent inhibition was calculated. Trolox solution (6-hydroxy-
2,5,7,8-tetramethylchroman-2-carboxylic acid) was used as an
antioxidant reference standard, and the results were expressed as
mol Trolox/g dry weight of plant extract.