Measurement of intracellular ROS. Inhibition of peroxyl-radical (AAPH; 600 μM)-induced formation of ROS in HepG2 cells pretreated with either Quercetin [20 μM], as a positive control, or increasing concentrations of Padma 28 (12.5–200 μg/ml). The mean percentages of DCF fluorescence, as a measure of ROS formation, are shown in relation to the AAPH-treated EtOH solvent control (set to 100%). Mean values ± S.E.M. of three independent experiments run in quadruplicates (*p <0.05, compared to AAPH-treated cells) are shown.