Dietary antioxidants as a source of hydrogen peroxide

Abstract

Studies of 54 antioxidants revealed that 27 of them, mainly polyphenols, generated hydrogen peroxide (H₂O₂) when added to Dulbecco's modified Eagle's medium (DMEM), other media used for culture of mammalian and yeast cells and phosphate-buffered saline. The most active antioxidants were: propyl gallate (PG), (-)-epigallocatechin gallate (EGCG) and quercetin (Q). Chelex treatment and iron chelators decreased H₂O₂ generation suggesting that transition metal ions catalyze antioxidant autoxidation and H₂O₂ production. Green tea also generated H₂O₂; tea prepared on tap water generated significantly more H₂O₂ than tea prepared on deionized water. Ascorbic acid decreased H₂O₂ production although it generated H₂O₂ itself, in the absence of other additives. Lemon added to the tea significantly reduced generation of H₂O₂. Hydrogen peroxide generated in the medium contributed to the cytotoxicity of PG, EGCG and Q to human prostate carcinoma DU-145 cells, since catalase increased the survival of the cells subjected to these compounds in vitro.

Keywords: (+)-Catechin, CID: 9064; (−)-Epicatechin gallate, CID: 107905; (−)-Epicatechin, CID: 72276; (−)-Epigallocatechin gallate, CID: 65064; (−)-Epigallocatechin, CID: 72277; 2,6-di-tert-Butyl-4-methylphenol, CID: 66609; Aminoguanidine hydrochloride, CID: 2734687; Antioxidant; Apigenin, CID: 5280443; Ascorbic acid; Autoxidation; Betanin, CID: 54600918; Buthylhydroxyanizole, CID: 24667; Caffeic acid, CID: 689043; Chlorogenic acid, CID: 1794427; Citric acid, CID: 311; Curcumin, CID: 969516; Daidzein, CID: 5281708; Ethoxyquin, CID: 3293; Gallic acid, CID: 370; Genistein, CID: 5280961; Gentisic acid, CID: 3469; Glycitein, CID: 5317750; Hesperetin, CID: 72281; Hesperidin, CID: 10621; Hydrocinnamic acid (3-Phenylpropionic acid), CID: 107; Hydrogen peroxide; Mangiferin, CID: 5281647; Melatonin, CID: 896; Metformin hydrochloride, CID: 14219; Morin, CID: 5281670; N-Acetylcysteine, CID: 12035; Naringenin, CID: 932; Naringin, CID: 442428; Oxaloacetic acid, CID: 970; Polyphenols; Propyl gallate, CID: 4947; Pyrogallol, CID: 1057; Pyruvic acid, CID: 1060; Quercetin, CID: 5280343; Rutin, CID: 5280805; Sinapic acid, CID: 637775; Sodium ascorbate, CID: 23667548; Sodium succinate, CID: 9020; Tea; Trolox, CID: 40634; Vanillic acid, CID: 8468; d-Isoascorbic acid, CID: 54675810; d-pantothenic acid hemicalcium, CID: 11306073; l-Ascorbic acid, CID: 54670067; l-Glutathione, CID: 124886; l-cysteine, CID: 5862; l-methionine, CID: 6137; p-Coumaric acid, CID: 637542; tert-Buthylhydroquinone, CID: 16043; trans-Ferulic acid, CID: 445858; trans-Resveratrol, CID: 445154; β-Carotene, CID: 5280489.