Identification of antioxidant peptides of hen egg-white lysozyme and evaluation of inhibition of lipid peroxidation and cytotoxicity in the Zebrafish model

Hen egg lysozyme was hydrolyzed with pepsin in situ on a cation-exchange column to isolate antioxidant peptides. The most cationic fraction was eluted with 1 M NaCl. Five positively charged peptides f(109-119) VAWRNRCKGTD, f(111-119) WRNRCKGTD, f(122-129) AWIRGCRL, f(123-129) WIRGCRL and f(124-129) IRGCRL were identified using tandem mass spectrometry. Using ORAC-FL , all five peptides presented antioxidant activity with values of (1970, 3123, 2743, 2393 and 0.313 A mu mol Trolox/A mu mol peptide), respectively. Using method TBARS in Zebrafish larvae, all five synthetic peptides were found to efficiently inhibit lipid peroxidation (36.8, 51.6, 55.56, 63.2, 61.0 % inhibition of lipid peroxidation), respectively. None of the five peptides were toxic in Zebrafish eggs and larvae at concentrations lower than 50 A mu g/ml. Concentrations higher than 50 A mu g/ml were toxic for both Zebrafish eggs and larvae.