Separation and identification of collagen peptides derived from enzymatic hydrolysate of Salmo salar skin and their anti-inflammatory activity in lipopolysaccharide (LPS)-induced RAW264.7 inflammatory model.

Inflammation is considered as a major risk for the pathogenesis of chronic diseases. Due to the adverse events caused by the long-term use of anti-inflammatory drugs, it is necessary to develop alternative and safe dietary supplements from natural products against inflammation. In this study, flavourzyme hydrolysate (for 0.5 hr) presented the strongest anti-inflammatory activity, which was further separated by ultrafiltration and column chromatography, followed by LC-MS/MS identification. Peptide APD, QA, KA, and WG were identified as anti-inflammatory peptides, which significantly reduced secretion of NO, IL-6, IL-1β, and TNF-α in inflammatory macrophages. Among them, peptide QA showed the best overall anti-inflammatory effect, with the IC 50 value against NO production of 849.3 μM. Most of the identified anti-inflammatory peptides were stably against digestion, and they had abundant frequencies in the α (I/II) chain of Salmo salar collagen. Our findings indicated the potential of S. salar skin hydrolysates as functional food to prevent inflammation. PRACTICAL APPLICATIONS: Long-term use of anti-inflammatory drugs causes adverse events like gastrorrhagia, and it is necessary to develop alternative and safe dietary supplements from natural products against inflammation. Salmo salar skin, as a major byproduct of total fish, has not been effectively utilized during processing. In this study, novel anti-inflammatory oligopeptides with high activities were separated and identified from S. salar skin gelatin hydrolysate, which were stably against digestion, and presented a high bioavailability and abundant frequencies in collagen. Our study highlighted the added value of aquatic by-products and suggested that S. salar skin collagen hydrolysate could be used as a promising dietary supplement against inflammatory diseases.