Isolation and characterisation of five novel antioxidant peptides from ethanol-soluble proteins hydrolysate of spotless smoothhound (Mustelus griseus) muscle

Abstract

Ethanol-soluble proteins (EP) were obtained from spotless smoothhound (Mustelus griseus) muscle, and the EP antioxidant hydrolysates (E-AMH) were prepared using papain. Five antioxidant peptides were isolated from the E-AMH using ultrafiltration and consecutive chromatographic methods including ion-exchange chromatography, gel filtration chromatography, and RP-HPLC, and their sequences were identified as Gly-Ala-Ala (217.3Da), Gly-Phe-Val-Gly (378.5Da), Gly-Ile-Ile-Ser-His-Arg (682.0Da), Glu-Leu-Leu-Ile (486.7Da), and Lys-Phe-Pro-Glu (519.6Da). All of these purified peptides exhibited high scavenging activity on hydroxyl radical (IC50 1.6337mg/ml, 0.8944mg/ml, 0.0769mg/ml, 0.1173mg/ml, and 0.1510mg/ml, respectively), ABTS radical (IC50 1.7541mg/ml, 1.3055mg/ml, 0.3493mg/ml, 0.3274mg/ml and 0.4645mg/ml, respectively), and superoxide radical (IC50 0.6714mg/ml, 0.3082mg/ml, 0.1508mg/ml, 0.1851mg/ml, and 0.2053mg/ml, respectively). These five purified peptides also effectively inhibited the autooxidation in linoleic acid model system. The antioxidant activities of these purified peptides were attributed to their amino acid compositions, sequences, and hydrophobicities. These results suggested that these five peptides isolated from the E-AMH of spotless smoothhound muscle were potent antioxidants and might be effectively used as food additives and pharmaceutical agents.