Extract of Ulmus davidiana Planch barks induced apoptosis in human hepatoma cell line HepG2

The cytotoxicity and mechanism of cell death induced by an extract of Ulmus davidiana Planch (UDP) were investigated. A 70 % ethanol extract of UDP exerted cytotoxic effects on HepG2 cells in a time- and dose-dependent manner caused a significant dose-dependent increase in the number of apoptotic cells. In addition, obvious shrinkage and destruction of the monolayer were observed in UDP-treated cells, but not in untreated cells. RT-PCR analysis revealed that the mRNA expression of p53 and c-myc was markedly increased in cells treated with the plant extract. In contrast, caspase-3 expression was induced after 1 h of incubation and then decreased at 3 h; however, it subsequently increased and remained at a relatively high level thereafter. Our data suggest the presence of a bioactive compound capable of killing liver carcinoma cells by apoptosis in a 70 % ethanol extract of UDP, and that the mechanism of apoptosis in the HepG2 cells included p53 and c-myc signaling.