Yu-Kuo Liu,1 Kuan-Hsing Chen,2 Yann-Lii Leu,3,4 Tzong-Der Way,5 Ling-Wei Wang,6,7 Yu-Jen Chen,8,9,* Yu-Ming Liu6–8,* 1Department of Chemical and Material Engineering, Chang Gung University, Kwei-Shan, Tao-Yuan, Taiwan; 2Kidney Research Center, Chang Gung Memorial Hospital, School of Medicine, 3Graduate Institute of Natural Products, College of Medicine, 4Chinese Herbal Medicine Research Team, Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan; 5Department of Biological Science and Technology, China Medical University, Taichung, Taiwan; 6Division of Radiation Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan; 7National Yang-Ming University, Taipei, Taiwan; 8School of Medicine, Institute of Traditional Medicine, National Yang Ming University, Taipei, Taiwan; 9Department of Radiation Oncology, Mackay Memorial Hospital, Taipei, Taiwan *These authors contributed equally to this workAbstract: Inducing apoptosis to susceptible cells is the major mechanism of most cytotoxic anticancer drugs in current use. Cinnamomum kanehirai Hayata (Lauraceae), a unique and native tree of Taiwan, is the major host for the medicinal fungus Antrodia cinnamomea which exhibits anti-cancer activity. Because of the scarcity of A. cinnamomea, C. kanehirai Hayata instead, is used as fork medicine in liver cancer. Here we observed the C. kanehirai Hayata ethanol extract could inhibit the cellular viability of both HepG2 and HA22T/VGH human hepatoma cell lines in a dose- and time-dependent manner. We found the mode of cell death was apoptosis according to cell morphological changes by Liu's stain, oligonucleosomal DNA fragmentation by gel electrophoresis, externalization of phosphotidyl serine by detecting Annexin V and hypoploid population by cell cycle analysis. Our results showed that the extracts caused cleavage of caspase-3 and increased enzyme activity of caspase-8 and caspase-9. Caspase 3 inhibitor partially reversed the viability inhibition by the extract. Furthermore, the up-regulation of Bax and down-regulation of Bcl-2 were also noted by the extract treatment. In conclusion, C. kanehirai Hayata ethanol extract induced intrinsic pathway of apoptosis through caspase-3 cascade in human hepatoma HA22T/VGH and HepG2 cells, which might shed new light on hepatoma therapy.Keywords: Antrodia cinnamomea, hepatoma, apoptosis, anticancer