Objective: This study was to evaluate the effect of two benzofuran derivatives on human liver hepatocellular carcinoma cells HepG2 and human hepatic L02 cells in vitro. Method: 5

6-dimethoxy-2-isopropenyl-benzofuran (compound 1) and 5-acetyl-6-methoxy-2-isopropenyl-benzofuran (compound 2) were isolated from Ligularia veitchiana (Hemsl.) Greenm.Trypan blue exclusion staining

2'

7'-dichlorofluorescin diacetate(DCFH-DA) fluorescence spectrophotometry

and ammonium molybdate colorimetric assay were used to evaluate cytotoxicity

reactive oxygen species (ROS) generation

and catalase activity respectively. Result: The results showed that IC50 of compound 1 and 2 on L02 cells are (171.2±3.3) mg ·L-1 and (79.0±4.1) mg ·L-1

higher than that on HepG2

(84.2±6.5) mg ·L-1 and (65.2±1.9) mg ·L-1

exhibited more potent cytotoxic effect on tumor cells.After treated with the half inhibitory concentration (IC50) of compound 1 and 2 for 48 hours

ROS generated in HepG2 cells were 1.6 and 3.2 folds to the control group

and 1.2 and 1.8 folds in L02 cells respectively.Higher ROS generations in HepG2 cells than L02 were found.The catalase activity decreased from the control group (17.2±1.7) U ·mg-1 to (12.8±0.4) and (6.4±0.1) U ·mg-1 after treated with compound 1 and 2 in HepG2 cell respectively

and decreased from the control group (17.7±1.2) U ·mg-1 to (14.3±1.5) and (8.6±0.5) U ·mg-1 in L02 cells. Higher catalase activity reduced in HepG2 cells than L02. Conclusion: According to the more potent cytotoxicity

the ROS generation increasing in HepG2 than L02

and the decreasing of catalase activity in HepG2 cells

we suppose that the mechanism of the cytotoxicity for these two benzofuran deravatives may relate to ROS theory.