Underlying action mechanism of a novel antioxidant peptide derived from Allium tuberosum Rottler protein hydrolysates and its protective effects on hydrogen peroxide induced cell injury

A novel antioxidant peptide from protein hydrolysate of Allium tuberosum Rottler was identified as Phe-Pro-Leu-Pro-Ser-Phe (FF-6). It could not only quench multiple radicals efficiently, but also promote cell survival by protecting against oxidative damage. The residue Leu played a vital role in radical-scavenging process and interaction with ABTS(center dot) (+) radicals. When substituted residue Leu with Ala, the radical-scavenging capacity and cytoprotective effect of FF-6 were almost lost. Moreover, the peptide could increase the expression level of proteins PI3K, Akt, phospho-Akt, mTOR, phospho-mTOR, but not affect peroxiredoxin-6. According to these results, the potential mechanism responsible for the protection of oxidative damage and promotion of cell survival was taken place through the PI3K/Akt/mTOR signaling pathway. These findings could be helpful for better elucidating the antioxidant mechanism and shed light on synthetic of alternative antioxidants with more potent activity as nutraceuticals or pharmaceuticals.