Annexin V-FITC/PI double staining was employed to quantify the apoptotic rate of MCF-7 cells. Briefly, cells were plated into 6-well plates at 2 × 105 cells per well and cultured for 12 h to allow their adhesion to the dish. After incubation with the respective IC10, IC30, IC50 concentrations of Cos, Dehy, CD, or VOSL for 48 h, cells were harvested by trypsinisation, and then were stained with annexin V-FITC/PI double fluorescence apoptosis detection kit (BD Biosciences) following the manufacturer’s instruction. After incubation for 15 min at room temperature in darkness, the apoptotic cells were detected using a FACScalibur System (BD Biosciences). Compensation was performed by single annexin and PI measurements and data were analyzed by FCS3 express software (De Novo software). Untreated cells were used as a negative control.