Dietary Antioxidants Influence IER5 Activation and DNA Repair: Implications for Radioprotection and Healthy Aging

Radioprotective agents derived from natural food sources represent promising candidates for reducing the harmful effects of ionizing radiation and supporting healthy aging. In this study, we investigated the effects of selected micronized bioactive compounds and their mixes on DNA damage response pathways in human retinal epithelial cells (hTERT-RPE1). Individual compounds and their combinations were applied to cultured cells, and the expression of IER5, a radiation-inducible gene associated with DNA repair and cell survival, was evaluated, showing that most potent compound to be lycopene and quercetin. Thus, in the next step, commonly consumed foods available on the Czech market rich in moth-tomato and garlic-were analyzed for their antioxidant capacity. The results revealed marked variability in antioxidant potential among food sources, with specific cultivars exhibiting significantly higher values. Importantly, experimental mixtures of pure and micronized compounds demonstrated distinct and sometimes opposing effects on IER5 expression. These findings indicate that the radioprotective activity of dietary antioxidants depends not only on the properties of individual compounds but also on their specific combinations. Our study provides evidence that phytochemicals such as quercetin, lycopene, but also partially resveratrol and curcumin can modulate DNA-repair-associated pathways and underscores their potential as combinatory agents in strategies aimed at promoting genomic stability and potentially healthy aging.