The relative 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging
capacity (DPPH) was evaluated according to the method
established by Cheng, Moore, and Yu (2006). The sample extracts
used in this assay were the same to the ones used in total phenolic
test. The test solution (0.1 mL) of sample extracts, Trolox standards,
or blank solvent control was added to 0.1 mL of freshly prepared
DPPH solution to initiate the reaction. The absorbance of the
reaction mixture was measured at 515 nm for 40 min of reaction in
the dark. DPPH values were calculated using areas under the curve
and expressed as micromoles of Trolox equivalents (TE) per gram
of dried weight sample.