*4.4. Antioxidant Activity of the Formulations Against LPS-Induced ROS Formation in Vero Cells*

The Vero cells that were grown on 96-well plates (1 × <sup>10</sup><sup>4</sup> cells/well) were washed from the growth medium and treated with 100 μL/well of the tested compounds (five μg/mL) and 10 μL/well LPS from *E. coli* serotype 055:B5 (Sigma, 1.0 μg/mL), which were both dissolved in PBS and cultured at 37 ◦C in a CO2-incubator for one hour. For the ROS levels measurement, 20 μL of 2,7-dichlorodihydrofluorescein diacetate (DCF-DA, Sigma, final concentration 10 μM) solution was added to each well, and the plates were incubated for 30 min at 37 ◦C. The intensity of DCF-DA fluorescence was measured at λex 485 n/λem 518 nm using the plate reader PHERAstar FS (BMG Labtech, Offenburg, Germany) [31].
