Purification and anti-inflammatory action of tripeptide from salmon pectoral fin byproduct protein hydrolysate

In this study, the anti-inflammatory peptide from salmon pectoral fin byproduct protein hydrolysate by pepsin hydrolysis, was purified and identified using Sephadex G-25 gel permeation chromatography, high performance liquid chromatography and time-of-flight liquid chromatography/tandem mass spectrometry (TOF LC/MS/MS). The purified anti-inflammatory peptide was identified to be a tripeptide (PAY). Lipopolysaccharide treatment significantly (p < 0.05) stimulated the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in RAW264.7 cells. However, PAY treatment significantly (p < 0.05) inhibited the production of NO by 63.80% and PGE2 by 45.33%. Western blotting analysis revealed that PAY significantly (p < 0.05) suppressed the protein expression of inducible nitric oxide synthase and cyclooxygenase-2, which are responsible for the production of NO and PGE2. Additionally, PAY treatment also significantly (p < 0.05) attenuated the production of pro-inflammatory cytokines, including tumour necrosis factor-α, interleukin-6 and -1β.