Induction of Necrosis in Human Liver Tumor Cells by α-Phellandrene

alpha-Phellandrene (alpha-PA) is a component of dietary spices and herbs. The effect of alpha-PA on anticancer is unclear. This study aims to investigate the effects of alpha-PA on liver tumor cell death fate. Human liver tumor (J5) cells were incubated with alpha-PA and analyzed for cell cycle distribution, expression of Bax, Bcl-2, poly (ADP-ribose) polymerase (PARP) protein, and caspase-3 activity of J5 cells, and levels of nitric oxide (NO) production, lactate dehydrogenase (LDH) leakage, and ATP depletion were also analyzed in this study. Results found that alpha-PA significantly (P < 0.05) decreased the cell viability of J5 cells after 24-h treatment. The cell cycle distribution, Bax, Bcl-2, PARP protein levels, and caspase-3 activity of J5 cells did not change for 24 h after treatment with 30 mu M alpha-PA. Reactive oxygen species levels significantly increased, mitochondrial membrane potential levels significantly decreased when J5 cells were treated with 30 mu M alpha-PA for 24 h (P < 0.05). Thirty mu M alpha-PA significantly (P < 0.05) increased the necrotic cell number, NO production, LDH leakage, and ATP depletion after 24 h of incubation. These results suggest that alpha-PA induced J5 cell necrosis but not apoptosis, and alpha-PA-induced necrosis possibly involved ATP depletion.