Polyphenolic apple extracts: effects of raw material and production method on antioxidant effectiveness and reduction of DNA damage in Caco-2 cells.
A diet rich in fruits and vegetables is commonly perceived to be associated with reduced cancer risk, attributed to its high content of polyphenols. As apples represent a major polyphenol source in Western countries, we studied differentially produced extracts (1-100 microg/mL): two from different apple juices (AEs), one from pomace (APE), and one peel extract (PE) on their potential to reduce DNA oxidation damage and induce antioxidant defense in Caco-2 cells. Additionally, we measured direct antioxidant capacity (TEAC/ORAC) of the extracts. Quercetin-rich PE and APE most effectively diminished DNA damage and ROS level after 24 h incubation (PE > APE), whereas the AEs were only moderately effective. GPx activity was diminished for all extracts, with AEs > APE > PE. Direct antioxidant activity decreased in the order AEs > PE > APE, displaying no significant correlation with cellular markers. In conclusion, apple phenolics at low, nutritionally relevant concentrations may protect intestinal cells from ROS-induced DNA damage, mediated by cellular defense mechanisms rather than by antioxidant activity.
Bellion
Phillip
P
Department of Chemistry, Division of Food Chemistry & Toxicology, University of Kaiserslautern, Erwin Schroedinger Strasse 52, 67663 Kaiserslautern, Germany.
Digles
Jasmin
J
Will
Frank
F
Dietrich
Helmut
H
Baum
Matthias
M
Eisenbrand
Gerhard
G
Janzowski
Christine
C
D000975:Antioxidants / Q000032:analysis* / Q000494:pharmacology; D018938:Caco-2 Cells; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects*; D005419:Flavonoids / Q000032:analysis* / Q000494:pharmacology; D006801:Humans; D027845:Malus / Q000737:chemistry*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D010636:Phenols / Q000032:analysis* / Q000494:pharmacology; D010936:Plant Extracts / Q000032:analysis* / Q000494:pharmacology; D059808:Polyphenols
D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols