Polyphenolic Apple Extracts and their Constituents Modulate DNA Strand Breaks and Oxidation Damage in Human Colon Carcinoma Cells

摘要

Diets rich in fruits and vegetables are associated with a lower risk of tumour incidence in the intestine and other sites. This is mainly attributed to second-ary plant constituents (e.g. polyphenols), displaying bioactive effects, such as prevention from DNA oxidation. We studied the potential of polyphenolic ex-tracts from apple juices (AE), pomace extraction juice (APE), and apple peel (PE) to reduce menadione-induced DNA damage in the human colon cell line Caco-2, in comparison to antioxidant capacity and polyphenol composition. DNA strand breaks/ oxidation damage were assessed by the alkaline Comet Assay with/ without the repair enzyme FPG; antioxidant capacity was meas-ured by ORAC and TEAC assays. All extracts reduced DNA strand breaks at low concentrations (1-3 μg/m1) whereas higher AE concentrations (≥ 10 μg/ml) dif-ferentially increased DNA damage. Reduction of DNA damage by the extracts could partially be explained by their polyphenol pattern, whereas no influence of direct antioxidant capacity was observed. In conclusion, apple phenolics at low, nutritional relevant concentrations may prevent intestinal cells from ROS-induced DNA damage.