Anti-oxidant, anti-inflammatory and immunomodulating properties of an enzymatic protein hydrolysate from yellow field pea seeds

Purpose Enzymatic protein hydrolysates of yellow pea seed have been shown to possess high anti-oxidant and anti-bacterial activities. The aim of this work was to confirm the anti-oxidant, anti-inflammatory and immunomodulating activities of an enzymatic protein hydrolysate of yellow field pea seeds. Methods The anti-oxidant and anti-inflammatory properties of peptides from yellow field pea proteins (Pisum sativum L.) were investigated in LPS/IFN-gamma-activated RAW 264.7 NO(-) macrophages. The immunomodulating potential of pea protein hydrolysate (PPH) was then studied in a murine model. Results Pea protein hydrolysate, after a 12 h pre-treatment, showed significant inhibition of NO production by activated macrophages up to 20%. Moreover, PPH significantly inhibited their secretion of pro-inflammatory cytokines, TNF-alpha- and IL-6, up to 35 and 80%, respectively. Oral administration of PPH in mice enhanced the phagocytic activity of their peritoneal macrophages and stimulated the gut mucosa immune response. The number of IgA+ cells was elevated in the small intestine lamina propria, accompanied by an increase in the number of IL-4+, IL-10+ and IFN-gamma+ cells. This was correlated to up-regulation of IL-6 secretion by small intestine epithelial cells (IEC), probably responsible for B-cell terminal differentiation to IgA-secreting cells. Moreover, PPH might have increased IL-6 production in IECs via the stimulation of toll-like receptors (TLRs) family, especially TLR2 and TLR4 since either anti-TLR2 or anti-TLR4 was able to completely abolish PPH-induced IL-6 secretion. Conclusions Enzymatic protein degradation confers antioxidant, anti-inflammatory and immunomodulating potentials to pea proteins, and the resulted peptides could be used as an alternative therapy for the prevention of inflammatory-related diseases.