Induction of apoptosis in cervical carcinoma HeLa cells by Petasites japonicus ethanol extracts

Petasites japonicus is a traditional medicine in Korea for treating carcinoma, bronchitis, and asthma. However, the molecular mechanisms of anti-cancer activity are not well understood. The purpose of this study was to confirm the anti-cancer activity of P. japonicus and its mechanism. Apoptosis was examined using morphological observation of nuclear changes and flow cytometry. Activation of apoptosis-related markers was detected. P. japonicus extract significantly inhibited HeLa cell growth in vitro in a dose-dependent manner. Induction of apoptosis by P. japonicus was mediated by up-regulation of Bax and down-regulation of Bcl-2. P. japonicus also activated caspase-9, capspase-3, and PARP, indicating induction of the mitochondrial intrinsic apoptosis pathway. We also confirmed that administration of P. japonicus significantly reduced tumor weight in the xenografted mice. Thus, P. japonicus was effective for inhibiting tumor growth in vitro and in vivo by inducing apoptosis, suggesting its usefulness as a potential anti-cancer agent.