Cellular Antioxidant Activity (CAA) Assay. The quantification of
cellular antioxidant activity was determined according to the method
of Wolfe and Liu (19) with a slight modification. HepG2 cells were plated
in a 96-wellmicrotiter plate at a density of 5104 cells/well.After 24 h, the
cells were treated with 100 μL of quercetin or extract plus 25 μMDCFHDAdissolved
in the treatmentmediumfor 1 h. The treatmentmediumwas
removed, and the cells were incubated with 100 μL of 1 mM AAPH.
Fluorescence was measured (excitation wavelength of 485 nm and emission
wavelength of 520 nm) with a FLUOstar galaxy fluorescence plate
reader (BMGLabtechnologies,Offenburg,Germany) at 37 Cevery5min
for 1 h. Final CAA values were calculated using the CAA unit at each
concentration of quercetin and