XXVI National Meeting in Medicinal Chemistry

Buffalo dairy products are an important source of bioactive peptides. These are inactive, since encrypted in their parent sequences, but turn active when released by fermentation or ripening during food processing, or by digestive enzymes during gastrointestinal transit.1 Once released, the bioactive peptides are able to exert either local or systemic pharmacological effects, involving specific biochemical pathways and leading to the identification of undisclosed drug-target interactions. This is why food-derived bioactive peptides, particularly from dairy products, are attractive tools for drug discovery campaigns.2 In the present study, to evaluate the biological activities of encrypted peptide sequences from buffalo ricotta cheese, a simulated gastrointestinal (GI) digestion of the raw material was performed.3 Chemical and pharmacological characterization of the digest leads to the identification of a novel peptide endowed with antioxidant and anti-hypertensive action. The GI digest was fractionated by Semiprep-HPLC and fractions were tested against reactive oxygen species (ROS) release in H2O2-treated intestinal epithelial cell line. UHPLC-PDA-MS/MS a -lactoglobulin peptide (SFNPTQL, BPR2) in the most active fraction. The peptide was synthesized via Fmoc chemistry solid phase peptide synthesis and pharmacologically characterized. Pharmacological assays revealed the antioxidant activity of BPR2, involving ROS reduction, Nuclear factor erythroid 2-related factor 2 (Nrf2) activation and cytoprotective enzymes expression. Bioavailability studies through Caco-2 cell monolayer3 revealed equal bi-directional transport and linear permeability of BPR2, consistent with a passive diffusion mechanism. In addition to its local effects, administration of BPR2 on mice mesenteric arteries counteracts the Angiotensin II-induced vasoconstriction by Nrf2 nuclear translocation, reduction of active form of Ras-related C3 botulinum toxin substrate 1 (Rac1) and NADPH oxidase activity. These data suggest a specific further highlight the role of buffalo ricotta cheese-derived peptides against oxidative stress related diseases and suggest their health promoting potential. Further studies are ongoing to identify the specific BPR2 structure-activity relationship and to identify its biological targets.