Potential anti-inflammatory activity of walnut protein derived peptide leucine-proline-phenylalanine in lipopolysaccharides-irritated RAW264.7 cells

The purpose of this study was to explore the anti-inflammatory mechanism of walnut peptide LPF in the LPS-induced RAW264.7 cells model. The walnut peptide LPF down-regulated the phagocytic ability and the production of nitric oxide (NO) induced by LPS-stimulated RAW264.7. Molecular docking analysis showed that the walnut peptide LPF can bind into the active pocket of inducible nitric oxide synthase (iNOS) with high affinity. Further, the mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and tumour necrosis factor-α (TNF-α) were suppressed by the walnut peptide LPF intervention. Later, we validated the under-expression of INOS protein by western blot. The decreased mRNA expression of IκB-α demonstrated the anti-inflammatory effects of the walnut peptide LPF were related to the regulation of the NF-κB signalling pathway. Our results suggest that the walnut peptide LPF has the potential to be developed as a functional food ingredient against inflammation.