From Traditional Spice to Functional Ingredient: Phenolic Profile and Bioactive Properties of Sicilian Rhus coriaria L. Fruit.

Dietary strategies focused on reducing sodium intake and increasing plant-based foods rich in bioactive compounds are increasingly recognized for preventing metabolic disorders. In this context, herbs and spices are valuable functional ingredients with sensory and health-promoting properties. Rhus coriaria L. (sumac), a traditional Mediterranean spice appreciated for its sour taste and rich phenolic profile, remains only partially characterized biologically. This study investigated the phenolic composition and biological activities of the aqueous extract of Sicilian sumac using chemical, enzymatic, and cell-based assays. HPLC-PDA/ESI-MS analysis revealed a profile dominated by gallic acid derivatives, with gallic acid (46.45 mg/g dried extract) and galloyl malic acid (7.16 mg/g) as the major constituents, alongside minor amounts of protocatechuic acid and the flavonol glycosides myricetin and quercetin rhamnoside. Antioxidant activity was evaluated by DPPH and ABTS assays, while antidiabetic potential was assessed through α-amylase and α-glucosidase inhibition compared with acarbose (IC50 = 2.2 mg/mL and 0.04 mg/mL, respectively). Antiglycation activity was assessed using the BSA-methylglyoxal model, and cytoprotective effects were evaluated in H2O2-stimulated HepG2 cells. The extract exhibited antioxidant, enzyme inhibitory, antiglycation, and ROS-reducing activities, supporting further investigation as a functional ingredient, while emphasizing that in vivo studies are required to confirm its biological efficacy.