Preparation of sea cucumber collagen hydrolysate and its inhibitory effect on α-glucosidases

Non-alcoholic fatty liver disease (NAFLD) is a chronic metabolic disorder characterized by excessive hepatic lipid accumulation. Emerging evidence suggests that digestive enzymes such as α-glucosidase regulate lipid and glucose homeostasis through postprandial metabolic pathways and may represent a potential therapeutic target for NAFLD management. This study investigated the α-glucosidase inhibitory activity of sea cucumber collagen peptides. Five collagen hydrolysates were prepared, among which the hydrolysate obtained by pepsin digestion for 2 h followed by trypsin digestion for 3 h (SDP 2 h + T 3 h) exhibited the strongest inhibitory activity. A peptide, RDDPEPSYK (RDD), was isolated and identified as a specific α-glucosidase inhibitor. RDD showed inhibitory efficacy comparable to acarbose and significantly reduced lipid accumulation by downregulating lipid synthesis-related proteins, including SREBP-1C and FAS. These findings suggest that sea cucumber collagen peptides may have potential applications in anti-obesity and anti-hepatic steatosis interventions.