Xylopine Induces Oxidative Stress and Causes G₂/M Phase Arrest, Triggering Caspase-Mediated Apoptosis by p53-Independent Pathway in HCT116 Cells

Figure 8

Effect of xylopine (XYL) in the levels of reactive oxygen species (ROS) of HCT116 cells and protection by N-acetyl-L-cysteine (NAC) and catalase determined by flow cytometry using DCF-DA staining. (a) ROS levels of HCT116 cells after 1 and 3 h incubation. (b) ROS levels of HCT116 cells pretreated with the antioxidant NAC and then treated with xylopine. (c) ROS levels of HCT116 cells pretreated with the antioxidant catalase and then treated with xylopine. For the protection assay, the cells were pretreated for 1 h with 5 mM NAC or 2000 UI catalase and then incubated with 14 μM xylopine for 1 h. The negative control (CTL) was treated with the vehicle (0.1% DMSO) used for diluting the compound tested. Hydrogen peroxide (H₂O₂, 200 μM), doxorubicin (DOX, 1 μM), and oxaliplatin (OXA, 2.5 μM) were used as positive controls. Data are presented as the mean ± S.E.M. of three independent experiments performed in duplicate or triplicate. Ten thousand events were evaluated per experiment, and cellular debris was omitted from the analysis. compared with the negative control by ANOVA followed by Student–Newman–Keuls test. compared with the respective treatment without inhibitor by ANOVA followed by Student–Newman–Keuls test.

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