Structural characterization of peroxyl radical oxidative products of antioxidant peptides from hydrolyzed proteins

• Published in: Heliyon Vol. 10; no. 9; p. e30588
• Main Authors: Esfandi, Ramak, Willmore, William G., Tsopmo, Apollinaire
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.05.2024; Elsevier
• Subjects: Antioxidant; Chemistry of antioxidant; Oxidation of peptides; Oxidation of peptides; Antioxidant; Chemistry of antioxidant
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2024.e30588

This work aimed to characterize oxidative products of five unique antioxidant peptides (P1: YFDEQNEQFR, P2: GQLLIVPQ, P3: SPFWNINAH, P4: NINAHSVVY, P5: RALPIDVL) from hydrolyzed oat proteins. Peptides were reacted with 2,2′-Azobis(2-amidinopropane) dihydrochloride, a common peroxyl radical generator. Chromatographic data showed that peptide P3 was the most oxidized (67 ± 4 %) while also displaying the most ability to scavenge radicals in the oxygen absorbance capacity assay (ORAC) with an activity of 2.16 ± 0.09 μM Trolox equivalents/μM peptide. Structural characterization using mass spectrometry showed the presence of four oxidative products of P3, three of which were mono-oxygenated and the fourth di-oxygenated. The identification of these oxidative products is new and provides an opportunity to investigate their biological function. A good correlation (r = 0.889) between the degree of oxidation and the ORAC data, demonstrates the usefulness of using oxidative peptide data to predict their radical scavenging activities.