Effect of Timosaponin AIII (TSAIII) on viability and cytotoxicity of human osteosarcoma and normal osteoblast cells. (A) Structure of Timosaponin AIII (TSAIII). (B) 143-B and HOS cells (human osteosarcoma cells) and MC3T3-E1 cells (normal osteoblasts) were exposed to various concentrations (0, 2, 4, 6, 8, and 10 μM) of TSAIII for 24 h, and cell viability was measured using the CCK8 assay. (C) Cell proliferation rate of human 143-B and HOS osteosarcoma cells exposed to TSAIII (0, 2, 4, 6, 8, and 10 μM) for 24 h was measured using a colony formation assay. (D) Regulation of cell cycle distribution and (E) cell death in human 143-B and HOS osteosarcoma cells exposed to various concentrations (0, 2, 4, and 6 μM) of TSAIII were analysed using Propidium Iodide (PI) staining or Annexin V/PI staining through flow cytometry. ** p < 0.01 versus control.