Annexin V-FITC/PI double staining coupled with flow cytometry revealed RT2 induces apoptosis in Caco-2 colon cancer cells. Cells were treated or not with increasing concentrations of RT2 (15, 30, and 60 µM) for 24 h. (a) The flow cytometry histograms indicate that RT2 treatment leads to an increase in the number of Caco-2 apoptotic cells. Live cells are in quadrant 3 (Q3, Annexin V-FITC negative and PI negative). Early apoptotic cells are in quadrant 4 (Q4, Annexin V-FITC positive and PI negative). Late apoptotic cells are in quadrant 2 (Q2, Annexin V-FITC positive and PI positive). Necrotic cells are in quadrant 1 (Q1, Annexin V-FITC negative and PI positive). (b) The bar chart quantifies the percentage of live, early, late, and total apoptotic cells. These data are represented as mean ± SD. Different letter(s) on the top of each bar are statistically different from each other (p < 0.05, n = 3).