2.9 Cell viability assay
H1299 and Vero cells seeded in 96-well plate (5×103cells/well) were treated with the indicated concentrations of CL extracts or each compounds for 24 h. Subsequently, WST-8 solution (Biomax, Korea) was added to each well and incubated for 2 h at 37°C in CO2 incubator. The absorbance of the water-soluble formazan dye formed was measured at 450 nm using SpectraMax iD5 Multi-Mode Microplate Reader (Molecular Devices, USA). The relative cell viability was expressed as a percentage relative to the untreated control cells.