Polyphenolic compounds and nutraceutical properties of old and new apple cultivars

Abstract Aim of the study was to characterize the nutritional composition of 11 apple varieties including 9 varieties from the Regional Repertory of Biodiversity of Marche (Italy). The qualitative and quantitative profiles of polyphenols were evaluated through HPLC‐DAD‐MS analysis. Antioxidant properties were evaluated by 1,1‐diphenyl‐2‐ picrilhydrazyl, ferric reducing antioxidant power, and oxygen radical absorbance capacity assays. The ability of apple extracts to inhibit glyco‐oxidative stress was studied using three experimental models: albumin glycated by incubation with fructose or methylglyoxal and human dermal fibroblasts incubated with high‐glucose (HG) concentration. The results demonstrated a variability in polyphenolic profile, radical scavenging capacity, and ability to inhibit non-enzymatic glycation of protein. The results showed that HG treatment increased the formation of reactive oxygen species, lipid hydroperoxides, and advanced glycation end products in cells with a decrease in total antioxidant capacity. Apple extracts were able to counteract the glycoxidizing action of high glucose, the protective effect was related to apple polyphenol content.