Purification and identification of anti-inflammatory peptides from sturgeon (Acipenser schrenckii) cartilage

Cartilage is a nonedible byproduct with little saleable value. However, previous studies have proposed the possibility of producing peptides from cartilage with immune function modulation potential. The current study aimed to investigate the potential anti-inflammatory activity of peptides derived from sturgeon (Acipenser schrenckii) cartilage in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Five peptide sequences, including four novel peptides, were identified from ethanol-soluble cartilage hydrolysates. Among these five peptides, LTGP, LLLE, LLEL and VGPAGPAGP reduced the production of nitric oxide (NO) and interleukin-6 (IL-6) while increasing interleukin-10 (IL-10) excretion. Transcriptome analysis suggested the inhibition of activated mitogen-activated protein kinase (MAPK) and interleukin-17 (IL-17) signaling pathways after LLEL intervention. MAPK, which is involved in the IL-17 signaling pathway, was further proved to be blocked by downregulating the phosphorylation of p38, extracellular-signal regulated protein kinase (ERK), and c-jun N-terminal kinase (JNK). This novel peptide offers an attractive approach to develop functional foods.