An identified antioxidant peptide obtained from ostrich (Struthio camelus) egg white protein hydrolysate shows wound healing properties

Context: Ostrich (Struthio camelus) egg possesses a high amount of food proteins and thus plays an important role in nutrition. Objective: Ostrich egg white proteins were hydrolyzed with pepsin and pancreatin to examine its antioxidant properties and further characterized the most active peptide. Materials and methods: Ostrich egg white protein hydrolysate (OEWPH) was fractionized using reversed phase high-pressure liquid chromatography (HPLC). The antioxidant activity of OEWPH and its HPLC fraction were investigated based on their scavenging capacityl, 1-dipheny1-2-picrylhydrazyl (DPPH) radical, 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), superoxide (O-2(center dot-)), hydroxyl (OH center dot-) radicals, and Cu+2 chelating. In a wound healing assay, paravertebral excision (1 cm diameter) was made on the skin and the percentage of wound closure was measured at defined intervals (0, 3, 7, and 14d). Results: A potent antioxidant peptide named DG-10 with the sequence DAESLSRLLG (Mw: 1060.18 0.5 Da) was identified from OEWPH. The peptide DG-10 showed DPPH (IC50 = 0.0085 mg/ml), ABTS'l (IC50 = 0.56 mg/ml), superoxide (IC50 = 0.36 mg/ml), and hydroxyl (IC50 = 0.4 mg/ml) radical scavenger and copper chelating activity (IC50 0.28 mg/ml). In vitro cultured HFLF-pl 5, the cell model, also revealed that DG-10 could protect HFLF-pl 5 cells against H202-treated necrosis. Ointment composed of DG-10 peptide exhibited wound-healing properties on adult rats (Wistar strain). The percentage of wound closure in peptide-treated group was 98% by day 14. Discussion and conclusion: Our results suggested that DG-10 is a natural agent obtained from ostrich egg possessing considerable antioxidant and wound-healing properties.