title: Anticarcinogenic antioxidants as inhibitors against intracellular oxidative stress.
abstract: Oxidative stress has been implicated in the pathogenesis of numerous diseases, including cancer. In the present study, the protective effect of natural antioxidants, such as quercetin and tea polyphenols, on intracellular oxidative stress was studied. Here we report a novel function of quercetin and tea polyphenols, as potential inhibitors of 4-hydroxy-2-nonenal (HNE)-induced intracellular oxidative stress and cytotoxicity. In rat liver epithelial RL34 cells, a potent electrophile HNE dramatically induced the productions of reactive oxygen species (ROS), which correlated well with the reduction in cell viability. We found that quercetin and tea polyphenols, such as epigallocatechin gallate and theaflavins and their gallate esters, significantly inhibited the HNE-induced ROS production and cytotoxicity. In addition, HNE induced a transient decrease in the mitochondrial membrane potential (delta psi), which was also retarded by the antioxidants. These data suggest that the antioxidants, such as quercetin and tea polyphenols, are inhibitors against mitochondrial ROS production.
authors.affiliation: Laboratory of Food and Biodynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Japan.
authors.forename: Q
authors.initials: Q
authors.lastname: Feng
authors.forename: T
authors.initials: T
authors.lastname: Kumagai
authors.forename: Y
authors.initials: Y
authors.lastname: Torii
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Osawa
authors.forename: K
authors.initials: K
authors.lastname: Uchida
mesh_terms: D000447:Aldehydes / Q000494:pharmacology; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D005419:Flavonoids; D007425:Intracellular Membranes / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects*; D010636:Phenols / Q000494:pharmacology; D011108:Polymers / Q000494:pharmacology; D011794:Quercetin / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D014407:Tumor Cells, Cultured
chemical_list: D000447:Aldehydes; D016588:Anticarcinogenic Agents; D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D011108:Polymers; D017382:Reactive Oxygen Species; D011794:Quercetin; C027576:4-hydroxy-2-nonenal