EGCG-meditated cyto- and genotoxicity in HaCat keratinocytes is impaired by cell-mediated clearance of auto-oxidation-derived H2O2: an algorithm for experimental setting correction.

Several lines of evidence suggest that besides antioxidant also prooxidant properties are crucially involved in cytotoxic and protective activities of the major green tea catechin epigallocatechin-3-gallate (EGCG) in vitro (Elbling et al., 2011). Furthermore recent data suggest that EGCG induces oxidative stress also in vivo (Li et al.

Hydrogen peroxide mediates EGCG-induced antioxidant protection in human keratinocytes.

The beneficial health effects of (-)-epigallocatechin-3-gallate (EGCG), the main catechin of green tea, have been attributed to complex interactions with a focus on antioxidative properties. Susceptibility to autoxidation and production of cytotoxic reactive oxygen species (ROS), mostly H(2)O(2), have been suggested to occur in vitro but also in vivo. In this study, we address whether autoxidation-derived H(2)O(2) may be involved in the cytoprotective effects of EGCG.

Green tea extract and (-)-epigallocatechin-3-gallate, the major tea catechin, exert oxidant but lack antioxidant activities.

Green tea is the most widely consumed beverage. It has attained high reputation as a health-promoting dietary component ascribed to the antioxidant activity of (-)-epigallocatechin-3-gallate (EGCG), its main polyphenolic constituent. Evidence is increasing that tea constituents can be cell damaging and pro-oxidant themselves.

Promyelocytic HL60 cells express NADPH oxidase and are excellent targets in a rapid spectrophotometric microplate assay for extracellular superoxide.

A great number of drugs, toxicants, and growth factors induce the generation of intermediary reactive oxygen species (ROS). The human promyelocytic leukemia HL60 cell line differentiated along the macrophage or neutrophil lineage is a model system that is frequently used for the generation of ROS by various agents. As a primary source of ROS the superoxide anion produced by an enzymatic complex, NADPH oxidase, is well established.