This work studies the supercritical carbon dioxide (SC-CO2) extractions of capillarisin from Artemisia capillaris T. and the effect of the extracts on the growth inhibition of two human hepatoma cells (Hep-G2, HUH7) and mouse liver cells (BNL). A two-factor central composite experimental design at 50 degrees C (323 K), a 2 h extraction time with pressures from 2000 psig (13.89 MPa) to 3000 psig (20.79 MPa) and an ethyl-acetate addition ratio from 5 to 10 wt%, were adopted to determine that the purity of capillarisin corresponds to the inhibition concentration (IC50 values) of the SC-CO2 extracts tested for Hep-G2 and HUH7 cells. The addition ratio of ethyl-acetate is the most important parameter in controlling the purity of capillarisin in the extracts. Experimental results indicated that adding 7.5 wt% ethyl-acetate to SC-CO2 extractions at 2500 psig (17.34 MPa) and 50 degrees C (323 K) yielded the highest purity of capillarisin (39.52 wt%) and the greatest growth inhibition for two hepatoma cells. The tested concentrations of these SC-CO2 extracts were from 15 to 400 mu g/mL revealed that the IC50 values of 72 h cultivated Hep-G2 and HUH7 cells were all less than 50 mu g/mL. (c) 2007 Elsevier B.V. All rights reserved.