Novel Peptides LFLLP and DFFL from Jack Bean Protein Hydrolysates Suppress the Inflammatory Response in Lipopolysaccharide-Stimulated RAW 264.7 Cells

The production of inflammatory cytokines such as tumor necrosis factor (TNF)-α by activated macrophage cells plays an important role in the development of intestinal inflammation. The present study investigated the anti-inflammatory effect of the protein hydrolysates prepared from the jack bean (JBPHs), <i>Canavalia ensiformis</i> (L.) DC, using the enzyme Alcalase, in a murine macrophage model, RAW 264.7 cells, which were stimulated by lipopolysaccharides. JBPHs reduced the TNF-α expression at the protein and mRNA levels through the downregulation of cellular signaling pathways involved in nuclear factor kappa B (NF-κB), extracellular signal-regulated kinase (ERK), and p38. A combination of mass spectrometry and in silico approaches identified 10 potential anti-inflammatory peptides in the JBPHs, including LFLLP and DFFL. Interestingly, while LFLLP targeted the NF-κB pathway, DFFL targeted p38 and ERK to suppress the TNF-α production in the RAW 264.7 cells. In addition, LFLLP and DFFL were localized in the cytosol of the cells. These results demonstrated that LFLLP and DFFL were incorporated by RAW 264.7 cells and, at least in part, contributed to the reduction in TNF-α by JBPHs. These peptides isolated from JBPHs may well be utilized as new alternatives to alleviate intestinal inflammation.