Anti-inflammatory peptides from enzymatic hydrolysates of tuna cooking juice

To produce and identify anti-inflammatory peptides, three commercial enzymes orientase, flavourzyme, and alcalase 2.4L were used to hydrolyze tuna cooking juice, and the protein hydrolysates were purified, before being evaluated for the ability to induce secretary and cellular responses in murine peritoneal macrophages RAW264.7. Alcalase hydrolysate (AH) exhibited the most potent inhibitory effect. AH was further purified using gel-filtration chromatography and high-performance liquid chromatography. The results showed that the peptide fractions with the molecular weight ranging from 204 to 1672.9 Da possessed the greatest anti-inflammatory activity. The amino acid sequences of the two anti-inflammatory peptides isolated from AH hydrolysates were Pro-Arg-Arg-Thr-Arg-Met-Met-Asn-Gly-Gly-Arg (1543.8 Da) and Met-Gly-Pro-Ala-Met-Met-Arg-Thr-Met-Pro-Gly (1211.5 Da). We thus conclude that anti-inflammatory hydrolysates from tuna cooking juice by-product may be useful ingredients in food and nutraceutical applications.