Neuroprotective peptides isolated from flavourzyme-pea protein hydrolysate protect human SH-SY5Y cells from Aβ1-42 induced apoptosis

Neuroprotective peptides derived from Flavourzyme®-pea protein hydrolysate (FPPH) were sequentially purified by chromatographies. Cell viability of β-amyloid peptide-induced oxidative damage in human neuroblastoma SH-SY5Y cells was used to explore neuroprotective effects of FPPH. Three novel neuroprotective peptides were obtained by liquid chromatography tandem mass spectrometry. In vitro effect of gastrointestinal proteases on neuroprotective effects of the three peptides was also investigated. The result suggested that the gastrointestinal proteases did not affect neuroprotective effects of the three novel peptides, which reveals the potential to ameliorate diseases caused by neurodegeneration. Pretreating SH-SY5Y cells with peptide GGPFKSPF (GF) before Aβ_1-42 treatment increased cell viability and reduced formation of reactive oxygen species. Decrease of mitochondrial membrane potential and anti-apoptotic proteins Bcl-2 induced by Aβ_1-42 can be restored by GF treatment. GF can remarkably decrease the contents of pro-apoptotic proteins, Bax and Caspase-3, inducing the activation of Akt/GSK-3β pathway by phosphorylation of Akt. GF exerted an antioxidant effect via Nrf2/HO-1 signaling pathway by activating Nrf2, reducing malondialdehyde level as well as increasing the expression of HO-1 and the activities of superoxide dismutase, catalase and glutathione peroxidase. As a results, GF had preventively potential as functional foods in Aβ–related neurodegenerative disease.