Figure 3: Assessment of apoptosis by Annexin V/PI on the alveolar human lung cancer cell line (A549). The cells were treated with 200 and 400 μg/mL saffron extract for 48 h (symbols (b), (c)) or media (control symbol (a)), and apoptosis was examined with flow cytometry after Annexin V-PI double staining. The necrotic cells lost cell membrane integrity that permits PI entry. Viable cells exhibit Annexin V (−)/PI (−) (symbol (a)); early apoptotic cells exhibit Annexin V (+)/PI (−) (symbol (b)); late apoptotic cells or necrotic cells exhibit Annexin V (+)/PI (+) (symbol (c)).