Figure 5.

TP4O induces the activation of antioxidants, and antioxidant reagents rescue TP4O cytotoxicity. (A) Western blot analysis of antioxidant proteins. Lysates of HCT116 and RKO cells were examined following treatment with the indicated concentrations of TP4O for 24 h. GAPDH was used as a loading control. (B) HCT116 and RKO cells were treated with 0 or 1,000 µM TP4O in the presence of vehicle, 20 mM NAC, 20 µM EB or 100 µM MnTBAP for 24 h, and cell viability was measured by WST-8 assay. The values for each group were compared with those obtained with 0 µM TP4O. The data are represented as the mean ± standard deviation. **P<0.01. The results were obtained from three independent experiments. TP4O, terpinen-4-ol; MnTBAP, manganese (III) tetrakis (4-benzoic acid) porphyrin chloride; SOD2, superoxide dismutase 2; GPX1, glutathione peroxidase 1; NAC, N-acetyl-L-cysteine; EB, ebselen; ns, not significant.