Novel antioxidant peptides from MFGM protein Hydrolysates: Separation, identification and effects on Dexamethasone-induced mitochondrial dysfunction

Milk fat globule membrane (MFGM) protein is a complex milk protein system with antioxidant property, which can alleviate skeletal muscle dysfunction caused by oxidative stress. In this study, peptide products of MFGM protein obtained through in vitro digestion were isolated and purified, and the composition and antioxidant activities of MFGM peptides (MFGMP) were identified and assessed using LC-MS/MS combined with molecular docking and in vitro approach. Three novel antioxidant peptides TGIIT, YAR and YYK were identified from MFGMPF1, among which TGIIT and YAR exhibited excellent antioxidant effects and protected dexamethasone (Dex)-induced L6 cells by enhancing mitochondrial function and biogenesis involving modulating Sirt-1/PGC-1α signaling pathway. Furthermore, YAR and TGIIT also significantly decreased expression of pro-apoptotic factors such as cyt-c, cleaved caspase-3 and caspase-9. Therefore, YAR and TGIIT, two novel antioxidant peptides, are expected to be utilized in functional food or medicine, providing an emerging role of MFGMP in maintaining anti-oxidant/oxidant status.