Cytoprotective Potential of Annurca Apple Polyphenols on Mercury-Induced Oxidative Stress in Human Erythrocytes

AbstractMercury (Hg) exposure is a major environmental risk factor, closely linked to oxidativestress and cardiovascular disease. Red blood cells (RBC), due to their high oxygenexposure and lack of repair mechanisms, are particularly sensitive to oxidative injury andare key indicators of systemic redox imbalance. This study evaluates the protective effectsof polyphenolic extracts from Annurca apple, specifically flesh and peel, from both ripeand unripe fruit, on HgCl2-exposed human RBCs. Key oxidative stress markers weremeasured, including ROS production, GSH levels, lipid peroxidation (TBARS), MetHbformation, SH group content, microvesicle (MV) generation, and morphological changes.Peel extracts, particularly those from ripe apples, consistently exhibited strongerantioxidant and cytoprotective effects than flesh extracts, effectively reversing Hginducedoxidative damage and preserving RBC integrity. Notably, these extracts restoredredox homeostasis and GSH levels, reduced ROS and TBARS accumulation, preventedMetHb formation, and mitigated MV release and morphological alterations. Theseprotective effects appear to involve multifactorial mechanisms. These findings highlightthe nutraceutical potential of Annurca apple extracts in counteracting heavy metalinducedoxidative stress and support their possible relevance for future studies aimed athealth protection and waste valorization.