Effect of EGCg on the proliferation of A549 cells. Morphological changes in A549 cells were shown to be dependent on the EGCg concentration. Cells exhibited a shape representative of A549 cells in the control (24 h incubation), whereas the cells lost their adhesion ability when treated with 25 μM EGCg. When treated with 100 μM ECGg, the cells were observed to float in the medium, exhibiting cell death (Fig. 2). The MTT assay was performed at 48 h after treatment with EGCg in the A549 cells. As shown in Fig. 3, the survival rate in the A549 cells was significantly suppressed by treatment with EGCg. The cell viability rate was markedly reduced at EGCg concentrations >25 μM, reaching a plateau at 50 μM. The IC50 (50% inhibition of cell growth) for EGCg in the A549 cells was 36.0 μM.