DPPH radical scavenging activity. DPPH radical scavenging
activity was determined as described by Wu, Chen,
and Shiau (2003) with a slight modification. Sample (5 mg/
mL; 1.5 mL) was added with 1.5 mL of 0.15 mM DPPH in 95%
methanol. The mixture was mixed vigorously and allowed
to stand at room temperature in the dark for 30 min. The
absorbance of the resulting solution was measured at
517 nm using a spectrophotometer (UV-1800, Shimadzu, Kyoto,
Japan). The blank was prepared in the same manner, except
that distilled water was used instead of the sample. A
standard curve was prepared using Trolox in the range of
10–60 lM. The activity was expressed as lmol Trolox equivalents
(TE)/g sample.