title: Can apple antioxidants inhibit tumor cell proliferation? Generation of H(2)O(2) during interaction of phenolic compounds with cell culture media.
abstract: It has recently been suggested that the ability of apple extracts to inhibit proliferation of tumor cells in vitro may be due to phenolic/flavonoid antioxidants. Our study demonstrates that this inhibition is caused indirectly by H(2)O(2) generated through interaction of the phenolics with the cell culture media. The results indicate that many previously reported effects of flavonoids and phenolic compounds on cultured cells may result from similar artifactual generation of oxidative stress. We suggest that in order to prevent such artifacts, the use of catalase and/or metmyoglobin in the presence of reducing agents should be considered as a method to decompose H(2)O(2) and prevent generation of other reactive oxygen species, which could affect cell proliferation. The use of tumor cells and "nontumor cells" in a bioassay to measure antioxidant activity, in this context, is potentially misleading and should be applied with caution.
authors: Department of Food Science, ARO Volcani Center, Bet Dagan 50250, Israel.
authors: Tair
authors: T
authors: Lapidot
authors: Michael D
authors: MD
authors: Walker
authors: Joseph
authors: J
authors: Kanner
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002109:Caffeic Acids / Q000737:chemistry / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D003300:Copper / Q000737:chemistry; D003470:Culture Media / Q000737:chemistry; D005638:Fruit / Q000737:chemistry*; D005707:Gallic Acid / Q000737:chemistry / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D027845:Malus / Q000737:chemistry*; D008786:Metmyoglobin / Q000494:pharmacology; D009369:Neoplasms / Q000473:pathology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010636:Phenols / Q000737:chemistry* / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry; D011794:Quercetin / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D002109:Caffeic Acids; D003470:Culture Media; D010636:Phenols; D010936:Plant Extracts; D008786:Metmyoglobin; D005707:Gallic Acid; D003300:Copper; D011794:Quercetin; D006861:Hydrogen Peroxide; D007501:Iron; D002374:Catalase; C040048:caffeic acid