Isolation, Identification, and Immunomodulatory Mechanism of Peptides from Lepidium meyenii (Maca) Protein Hydrolysate

Maca is a protein-enriched edible plant with immunomodulatory activity. However, the role of proteins in theimmunomodulatory activity of maca is unclear. In this study, peptide products of maca proteins obtained through in vitrogastrointestinal digestion were isolated and purified, and the immunomodulatory activities of these peptides were assessed inmacrophages (RAW 264.7 cells). The results show that the maca protein hydrolysate enhanced the phagocytic capacity and NO,TNF-alpha, and IL-6 secretion of RAW 264.7 cells. Forty-five peptides from known proteins of maca or the cruciferous family wereidentified by ultraperformance liquid chromatography-tandem mass spectrometry in the hydrolysate, and the peptide RNPFLPexhibited the strongest immunomodulatory activity. Antibody blocking, siRNA, pathway inhibitors, and western blot assays showedthat RNPFLP-activated RAW 264.7 cells through the NF-Kappa B and MAPK signaling pathways mediated by TLR2 and TLR4 receptors.An analysis of the structure-activity relationship showed that the N9-H60active site in arginine plays an important role in theimmunomodulatory activity of RNPFLP. This study provides a new understanding of the immunomodulatory activity of maca.

Automated summary

This study demonstrates that the hydrolysate of Maca protein enhances the immunomodulatory activity in macrophages and identifies the peptide RNPFLP as the most potent immunomodulatory peptide in the hydrolysate. Experimental evidence shows that RNPFLP activates macrophages through the NF-Kappa B and MAPK signaling pathways mediated by TLR2 and TLR4 receptors. Furthermore, the study reveals the important role of the N9-H60 active site in arginine in the immunomodulatory activity of RNPFLP.