Antibacterial peptides from barbel muscle protein hydrolysates: Activity against some pathogenic bacteria

Peptides obtained by enzymatic hydrolysis of fish proteins exhibit not only nutritional but also biological properties of dietary uses, or even therapeutic potential. The objective of the present study was to isolate and characterize peptides from the protein hydrolysates of barbel muscle with antibacterial activity against Gram-positive (Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, Micrococcus luteus and Bacillus cereus) and Gram-negative (Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Klebsiella pneumoniae and Enterobacter sp.) bacteria. Barbel muscle protein hydrolysates (BMPHs), obtained by treatment with Alcalase (R) (DH = 6.6%), was fractionated by size exclusion chromatography on a Sephadex G-25 and purified by reversed-phase high performance liquid chromatography (RP-HPLC). The molecular masses and amino acid sequences of these peptides were determined using ESI-MS and ESI-MS/MS, respectively. Eleven peptides in FII-1, FII-2, FII-3 and FII-4 sub-fractions separated by RP-HPLC were identified. The most active peptide fraction (FII-3) contained three peptides: Ala-Ala-Ala-Leu; Ala-Ala-Gly-Gly-Val and Ala-Ala-Val-Lys-Met. These peptides don't show hemolytic activity towards bovine erythrocytes. These results suggest that some peptides from barbel could be a beneficial ingredient for nutraceuticals. (C) 2013 Elsevier Ltd. All rights reserved.