title: Green tea polyphenol epigallocatechin-3-gallate differentially modulates oxidative stress in PC12 cell compartments.
abstract: Tea polyphenols have been reported to be potent antioxidants and beneficial in oxidative stress related diseases. Prooxidant effects of tea polyphenols have also been reported in cell culture systems. In the present study, we have studied oxidative stress in the subcellular compartments of PC12 cells after treatment with different concentrations of the green tea polyphenol, epigallocatechin-3-gallate (EGCG). We have demonstrated that EGCG has differentially affected the production of reactive oxygen species (ROS), glutathione (GSH) metabolism and cytochrome P450 2E1 activity in the different subcellular compartments in PC12 cells. Our results have shown that although the cell survival was not inhibited by EGCG, there was, however, an increased DNA breakdown and activation of apoptotic markers, caspase 3 and poly- (ADP-ribose) polymerase (PARP) at higher concentrations of EGCG treatment. Our results suggest that the differential effects of EGCG might be related to the alterations in oxidative stress, GSH pools and CYP2E1 activity in different cellular compartments. These results may have implications in determining the chemopreventive therapeutic use of tea polyphenols in vivo.
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, United Arab Emirates. h.raza@uaeu.ac.ae
authors.forename: Haider
authors.initials: H
authors.lastname: Raza
authors.forename: Annie
authors.initials: A
authors.lastname: John
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D019392:Cytochrome P-450 CYP2E1 / Q000096:biosynthesis; D053938:DNA Fragmentation / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004790:Enzyme Induction; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects*; D016716:PC12 Cells; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D013778:Tetrazolium Salts; D013844:Thiazoles
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D013778:Tetrazolium Salts; D013844:Thiazoles; D002392:Catechin; C045651:epigallocatechin gallate; D019392:Cytochrome P-450 CYP2E1; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; C022616:thiazolyl blue; D005978:Glutathione