Effects of HCT on DNA condensation, damage and apoptosis in human lung cancer A549 cells. (A) A549 cells stained with DAPI to observe DNA condensation after 24 h of treatment with 500 μg/ml of HCT. (B) A549 cells were examined DNA damage by Comet assay after 24 h of treatment with 500 μg/ml of HCT. Cells were photographed under fluoresce microscopy (x200) as described in Materials and Methods. (C) A549 cells were treated with HCT (0, 125, 250 and 500 μg/ml) for 24 h, and then were harvested for determination the sub-G1 (apoptosis) cell population by flow cytometry as described in Materials and Methods. (D) The bar diagram of the length of Comet tail. The experiments were performed in triplicate (n = 3). *p < 0.05, ***p < 0.001 was considered significantly different in comparison with the control.