Role of reactive oxygen species from the green tea catechin, (-)-epigallocatechin-3-gallate in growth modulation of intestinal cells

The tea catechin (-)-epigallocatechin-3-gallate (EGCG) inhibits cancer cell proliferation and induces apoptosis. Effects of EGCG on growth of immortalized intestinal and colon cancer cells and involvement of reactive oxygen species (ROS) were studied. Low concentrations of EGCG (< 20 mu M) stimulated cell growth (up to 60%) and high concentrations were inhibitory and induced apoptosis. H2O2 at concentrations similar to levels generated by low dosage EGCG (< 5 mu M) stimulated cell growth. Addition of SOD and catalase to EGCG-treated cells reduced these effects, suggesting a role for EGCG-produced ROS. EGCG produced H2O2 in a cell culture medium. Fetal bovine serum and bovine serum albumin reduced cell associated EGCG by 90% and decreased growth inhibitory effects and H2O2 generation from EGCG slightly. EGCG modulated intestinal cell growth either by induction of cell death or by growth stimulation via ROS generation in a culture medium.