Antioxidant capacity of phenolic compounds as well as their tyrosinase oxidation products in THP1 (A) and EA.hy 926 (B) cells. In order to stimulate ROS production, phorbol 12-myristate 13-acetate (PMA) was added to THP1 cells and 2,3-dimethoxy-1,4-naphtoquinone (DMNQ) to EA.hy 926 cells, respectively. Due to interaction with ROS, added L-012 exhibits chemiluminescence (CL), which was detected. The PMA/DMNQ lines represent maximum ROS production by stimulated cells. The dimethyl sulfoxide (DMSO) line shows the ROS signal in cells without stimulation. Buffer: citrate buffer (0.1M, pH 5.0) without phenolic compounds.