(A) Percentage of apoptotic cell induction by antcin K-treated Hep 3B cells. Cells were exposed to 0μM, 80μM, 100μM, and 125μM antcin K for 24 hours, and the distribution of apoptosis (lower right panel) was assessed by annexin V-FITC/PI assay. Effect of antcin K on ROS generation and ADP/ATP ratio in Hep 3B cells. (B) After incubation of the cells with 0μM, 80μM, 100μM, and 125μM antcin K for 24 hours, the fluorescence intensity of DCFH-DA was analyzed by flow cytometry. (C) Effect of antcin K on the degree of fluorescence intensity of DiOC6 in Hep 3B cells. After incubation of the cells with 0μM, 80μM, 100μM, and 125μM antcin K for 48 hours, the mitochondrial membrane potential was analyzed by flow cytometry. (D) After incubation of the cells with 0μM, 80μM, 100μM, and 125μM antcin K for 48 hours, the ADP/ATP ratio was determined by bioluminescence. Data are expressed as mean ± SD from one of three independent experiments and analyzed statistically using one-way ANOVA and Duncan's test. Different letters (a–d) represent statistically significant differences among treatments (p < 0.05). ADP/ATP = adenosine diphosphate/adenosine triphosphate; ANOVA = analysis of variance; DCFH-DA = dihydrodichlorofluorescein diacetate; DiOC6 = 3,3′-dihexyloxacarbocyanine iodide; MFI = mean fluorescence intensity; PI = propidium iodide; ROS = reactive oxygen species; SD = standard deviation.