Apoptotic responses to β-elemene challenge in A2780 and A2780/CP cell lines. A: Flow cytometry of annexin V-stained cells. Cells were treated with β-elemene at the indicated concentrations for 48 h and then stained with fluorescein isothiocyanate (FITC)-labeled annexin V and propidium iodide to detect cell membrane changes, as described in the Materials and Methods. Untreated cells were used as controls. B and C: Small nucleotide fragments, produced as a result of cell apoptosis, were quantified by ELISA using a commercially available apoptosis detection kit. The enrichment factor, which correlates with the number of apoptotic cells, is shown as an apoptotic index. Cells were treated with β-elemene at the indicated concentrations for 24, 48, and 72 h. Data are representative of three independent experiments. *p<0.05 and #p<0.01, vs. untreated control groups.