Tumor Cell Doubling Time: ECG versus EGCG Figure 5 shows the influence of the four epicatechins on cell doubling time. ECG and/or EGCG prolonged the doubling (14) EGC and ECG inhibited the growth of a human lung cancer cell line, PC-9 cells as potently as did EGCG, but EC did not show significant growth inhibition. The mechanism of growth inhibition by EGCG was studied in relation to cell-cycle regulation. EGCG (50 and 100 mM) increased the percentages of cells in the G 