Ovomucoid hydrolysates prepared using alcalase suppress adipogenesis at an early stage of 3T3-L1 cell differentiation

The effects of ovomucoid (OVM), a by-product of egg white, and its hydrolysates on adipocyte differentiation and lipid accumulation were investigated. The OVM hydrolyzed using Alcalase® and pepsin was named AH and PH, respectively. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis revealed significant changes in molecular weight of both hydrolysates, with AH showing a higher degree of hydrolysis. AH exhibited a more pronounced inhibitory effect on fat accumulation than PH. In in vitro experiments, AH and PH suppressed lipid accumulation during 3T3-L1 adipocyte differentiation, with AH inhibiting lipid accumulation most effectively. Oil red O staining and triglyceride measurements revealed lipid reduction in AH-treated cells, indicating that AH plays a major role in preventing lipid accumulation in adipocytes. In addition, AH inhibited the expression of lipid transcription factors (CCAAT/enhancer-binding protein alpha (C/EBP-α), peroxisome proliferator-activated receptor gamma (PPAR-γ), and sterol regulatory element-binding proteins (SREBP-1c)), adipogenesis-related factors (fatty acid synthase (FAS) and ACC1), insulin-related factors (insulin receptor substrate (IRS2) and protein kinase B (AKT2)), and lipolysis-related factors (glycerol-3-phosphate acyltransferase (GPAT), CD36, and lipoprotein lipase (LPL)) in a concentration-dependent manner. Specifically, the effect of AH was most pronounced in the early stages of adipocyte differentiation, where it activated AMPK early to associate energy homeostasis and downregulate genes important for cell cycle and lipid formation. This study suggests that OVM hydrolysates prepared using Alcalase® may contribute to the development of new strategies for the obesity treatment market.