(A) Effect of Piperine (0, 8, 16, or 20 μM) on the mitochondrial membrane potential (ΔΨm) of ovarian cancer cell line A2780. (B) Effect of Piperine (0, 8, 16, or 20 μM) on the cytosolic cytochrome c, PARP, and cleaved PARP protein expression of ovarian cancer cell line A2780. (C) Effect of Piperine (0, 8, 16, or 20 μM) on caspase-3, caspase-8, and caspase-9 activities of ovarian cancer cell line A2780. (D) Effect of specific caspase inhibitors Z-DEVD-FMK (caspase-3), Z-IETD-FMK (caspase-8), or Z-LEDH-FMK (caspase-9) on apoptosis of ovarian cancer cell line A2780 induced by Piperine (20 μM). Data shown are mean ± SD of three similar experiments. *P<0.05 and **P<0.01 as compared with the control group.