Purification and characterization of a novel antioxidative peptide from duck skin by-products that protects liver against oxidative damage

The peptide was purified from duck skin by-products using a reverse phase high performance liquid chromatography (RP-HPLC), and indentify the antioxidant activity. The sequence of the antioxidative peptide was identified as His-Thr-Val-Gln-Cys-Met-Phe-Gln (molecular weight of 941.43 Da). In addition, the IC50 value of the antioxidative peptide for hydroxyl. DPPH, alkyl, and superoxide radical scavenging activity were 32.6, 22.7, 55.1, and 49.8 mu g/ml, respectively. In addition, we also evaluated the protective effects of peptide on 3.5% alcohol-induced damage in normal liver cells. The peptide inhibited productions of reactive oxygen species (ROS), and cell death against alcohol-induced liver cell damage. It was presumed that the peptide was involved in regulation of apoptosis-related pathway in the cell environments. In addition, the antioxidant activity of the gelatin hydrolysates (complex treatment of collagenase and pepsin) was estimated in vivo. The rats were randomly divided into six group (n = 7), and treated with 40% alcohol for 15 days, which resulted in lower self-antioxidant capacities as well as increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values in blood and liver. Further, antioxidative enzyme (superoxide dismutase; SOD, catalase; CAT, and glutathione peroxidase; GPx) levels in cultured liver cells were increased in the presence of the gelatin hydrolysates. These results indicate that the enzymatic hydrolysates from duck skin by-products possess a potent biological activity. (C) 2012 Elsevier Ltd. All rights reserved.