Identification of immunomodulatory peptides from zein hydrolysates

Food protein-derived bioactive peptides have been recognized as a promising candidate for the development of functional foods or nutraceuticals. Peptides exhibiting antioxidant, anti-proliferative and anti-hypertensive activities have been characterized from corn proteins while the knowledge on the presence of immunomodulatory peptides in corn proteins is limited. The objective of this study was to identify the immunomodulatory peptides from corn proteins using interleukin 6 (IL-6) in human macrophage-like U937 cells as the marker. Results indicated that zein protein hydrolysate digested by thermolysin showed a high yield of peptides with potent activity, which was then used for further fractionation by RP-HPLC. We identified five peptides using LC–MS/MS, among which, peptide FLPFNQL showed the highest activity reducing IL-6 production by 57.7% ± 6.1%.