The antioxidant capacity was evaluated by ABTS and DPPH
radical scavenging activity. The ABTS radical cation (ABTS+) was
produced by reacting 7 mM ABTS with 2.45 mM potassium persulfate
(final concentration) and allowing the mixture to stand in the
dark for at least 6 h at room temperature prior to use. The ABTS+
solution was diluted to an absorbance of 0.7 ± 0.05 at 734 nm
(CT-2200 spectrophotometer, ChromTech, Singapore). For the