Effect of compound 7g on apoptosis of SW620 and HT29 cells. (A) Fluorescence microscopy images of Hoechst 33342. SW620 and HT29 cells were treated with compound 7g for 48 h at 0, 25, 50, and 75 μM, and then analyzed by Hoechst 33,342 staining and fluorescence microscopy. The red arrow indicates an apoptotic cell and chromatin condensation. (B) SW620 and HT29 cells treated with compound 7g were stained with annexin V/PI. The apoptosis rate of cells treated with compound 7g for 48 h at 0, 25, 50, and 75 μM was detected by flow cytometry. Each point represents the average of three independent experiments. Data were shown as the mean ± SD. (C) The effect of compound 7g on the expression level of apoptosis-related proteins. SW620 and HT29 cells were treated with compound 7g for 48 h at four concentrations (0, 25, 50, and 75 μM). Then, the contents of apoptosis-related proteins were measured using western blot. In addition, the relative density of apoptosis related-proteins was also analyzed by the Tanon Gis Software. Every value is the average of three independent experiments. Data are shown as the mean ± SD. * = p < 0.05; ** = p < 0.01.