The samples (25 μl) were mixed with 225 μl of Fox’s working solution and incubated during 30 min. After the absorbance intensity was measured at 560 nm in a 96-wells Microplate reader. Experiments in the presence of catalase (incubated during 30 min) were carried out to establish the possible generation of hydrogen peroxide. Total hydroperoxide concentration was determined using a calibration curve (r2 = 0.9976; slope: 0.1799; intercept: 0.0579) using a commercial H2O2 solution, and data were expressed as μM equivalents of H2O2.