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Formation of hydrogen peroxide in cell culture media by apple polyphenols and its effect on antioxidant biomarkers in the colon cell line HT‐29
Author(s) -
Bellion Phillip,
Olk Melanie,
Will Frank,
Dietrich Helmut,
Baum Matthias,
Eisenbrand Gerhard,
Janzowski Christine
Publication year - 2009
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.200800456
Subject(s) - polyphenol , chemistry , antioxidant , catalase , pro oxidant , hydrogen peroxide , reactive oxygen species , superoxide dismutase , biochemistry , glutathione , quercetin , food science , enzyme
Abstract Beneficial health effects of diets containing fruits have partly been attributed to polyphenols which display a spectrum of bioactive effects, including antioxidant activity. However, polyphenols can also exert prooxidative effects in vitro . In this study, polyphenol‐mediated hydrogen peroxide (H 2 O 2 ) formation was determined after incubation of apple juice extracts (AEs) and polyphenols in cell culture media. Effects of extracellular H 2 O 2 on total glutathione (tGSH; =GSH + GSSG) and cellular reactive oxygen species (ROS) level of HT‐29 cells were studied by coincubation ± catalase (CAT). AEs (⪈30 μg/mL) significantly generated H 2 O 2 in DMEM, depending on their composition. Similarly, H 2 O 2 was measured for individual apple polyphenols/degradation products (phenolic acids > epicatechin, flavonols > dihydrochalcones). Highest concentrations were generated by compounds bearing the o ‐catechol moiety. H 2 O 2 formation was found to be pH dependent; addition of CAT caused a complete decomposition of H 2 O 2 whereas superoxide dismutase was less/not effective. At incubation of HT‐29 cells with quercetin (1–100 μM), generated H 2 O 2 slightly contributed to antioxidant cell protection by modulation of tGSH‐ and ROS‐level. In conclusion, H 2 O 2 generation in vitro by polyphenols has to be taken into consideration when interpreting results of such cell culture experiments. Unphysiologically high polyphenol concentrations, favoring substantial H 2 O 2 formation, are not expected to be met in vivo , even under conditions of high end nutritional uptake.