Reagents were thoroughly mixed and let stand
for 16 h in a dark environment. Afterward, absolute ethanol was mixed with the ABTS+ radical (ABTS radical solution) until reaching
an absorbance of 0.70 ± 0.02 at 754 nm. A volume of 3.920 mL
of the ABTS radical solution were taken and placed in a 1 cm spectrophotometer
cuvette; the initial absorbance was measure (Ai).