Induction of apoptosis on ginsenosides-treated HK-1 cells. HK-1 cells were treated with 20(S)-Rh2 (15 μM), CK (15 μM), PD (10 μM) and PPD (10 μM) for 24 h in 1% FBS RPMI 1640 medium. The cell cycle was then evaluated by propidium iodide staining and flow cytometric analysis. The data were analyzed by the Cell Quest and the Modfit LT Version 3.0 software to determine the percentage of cells in different cell cycle phases. Apoptosis was examined by comparing the sub-G1 population in HK-1 cells treated with or without ginsenosides. (A) Representative histograms of three independent experiments. (B) Statistical analysis on the percentage of sub-G0/G1 populations. Results were presented as mean ± SD from three independent experiments. *P < 0.05 and **P < 0.01 compared to the DMSO control group. #P < 0.05 compared to the ethanol control group.