Annurca Apple By-Products at Different Ripening Stages Inhibit AGE Formation and Protect Against AGE-Induced Cytotoxicity Through Antioxidant Activity

Annurca apple extract is gaining growing attention for its beneficial properties, particularly its outstanding antioxidant activity. Using a combination of biophysical, cell, and molecular biology techniques, this study investigates the sustainable valorization of Annurca apple by-products at different ripening stages and their role in the formation of advanced glycation end-products (AGEs), as well as in protection against AGE-related cytotoxicity. AGEs are a class of compounds formed by non-enzymatic reactions between reducing sugars and proteins, lipids, or nucleic acids. They can be produced endogenously or ingested through dietary sources and tobacco smoke. AGEs accumulate in nearly all mammalian tissues and are linked to various health issues, such as diabetes and its related complications, cardiovascular disease, and neurodegenerative disorders. Our data show that Annurca apple by-products at different ripening stages differentially counteract AGEs' formation by inhibiting protein glycation and protect against AGE-induced cytotoxicity in endothelial cells. In particular, the extracts reduce AGE-induced reactive oxygen species (ROS) production, thereby inhibiting MAPK signaling pathways and caspase-3 activation. Moreover, ripening significantly enhances the concentration of bioactive compounds and the extent of cellular protection. This study highlights new beneficial properties of Annurca apple extracts and suggests that adopting nutritional interventions may support health and potentially reduce the risk of complications associated with AGE accumulation.