Figure 4.

EE-TT significantly reduced the ROS activity while increasing SOD activity in H₂O₂-treated ARPE-19 cells. ARPE-19 cells were pretreated with or without 1 mM H₂O₂ for 24 h, followed by a 24 h exposure to ethanol extracts of Tribulus terrestris (EE-TT): (a) The intracellular ROS activities were measured and analyzed by a flow cytometer. ROS activity of each sample was presented by the mean of fluorescence intensity (MFI) of DCF; (b) The activities of intracellular SOD were measured by a SOD activity assay kit. The SOD levels were normalized against per milligram protein. (c) Comparison of total antioxidant capacity of EE-TT and Trolox (an analogue of vitamin E, a positive antioxidant control). All data are shown as mean ± SD (n = 3). ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001 vs. the samples of control group (nontreated cells); ^#p < 0.05, ^##p < 0.01, ^###p < 0.001 vs. H₂O₂ only treated group.