Polyphenol profiling and multi-target antioxidant, anti-inflammatory and antidiabetic activity of Sorbus commixta Hedl. leaves

Abstract Sorbus commixta , a plant from the Rosaceae family, is native to Asia and cultivated in Europe and North America. Here, we evaluated the potential of S. commixta leaves as a source of biologically active compounds, including rare flavanones. The methanol-water extract (ME) and its bioactive polyphenol-enriched fractions were assessed for phytochemical composition, biological activity, and composition-activity relationships. A total of 78 compounds were identified by UHPLC-PDA-ESI-MS/MS, with a content reaching 589 mg/g of dry weight. Among the tested samples, ME and the n -butanol fraction (BF) exhibited the strongest biological effects. Both significantly protected human plasma components against peroxynitrite-induced oxidative and nitrative stress (ex vivo model) and inhibited the release of pro-inflammatory cytokines (IL-1β, IL-2, TNF-α) from stimulated human peripheral blood mononuclear cells in vitro. The BF fraction also demonstrated pronounced antidiabetic activity, showing approximately 17- to 26-fold stronger effects than acarbose and aminoguanidine in inhibiting α-glucosidase and the formation of advanced glycation end products in vitro. Statistical analysis revealed significant correlation of the observed effects with polymeric proanthocyanidins, flavonol diglycosides, caffeoylquinic acids, and monoglycosides of flavonols and flavanones. These findings support further in vivo investigation of S. commixta leaf extracts and highlight the need for their standardised quality control strategies.