*2.3. Test Solutions*

The range of the extract concentrations for the cytotoxicity tests was selected considering the concentration to be incorporated in wine (100 μg/mL). Serial test solutions (0–100 μg/mL) were prepared from stock solution (1000 μg/mL) in dimethyl sulfoxide (DMSO), being the final concentration in DMSO below 0.5%.

Concentrations of the extract used for both oxidative stress assays were calculated based on the cytotoxicity study previously performed. The mean effective concentration (EC50) value obtained (31.18 μg/mL and 20.56 μg/mL in HepG2, and 55.77 μg/mL and 39.02 μg/mL in Caco-2 cells for 24 h and 48 h, respectively) was chosen as the highest exposure concentration, along with the fractions EC50/<sup>2</sup> and EC50/4.

To measure protection and reversion abilities, test solutions of the extract to cell viability greater than 75% were selected (EC50/<sup>2</sup> and EC50/4).
