Boarfish (Capros aper) protein hydrolysate has potent insulinotropic and GLP‐1 secretory activity in vitro and acute glucose lowering effects in mice

Summary The anti‐diabetic actions of a boarfish protein hydrolysate ( BPH ) were investigated in cultured cells and mice. A boarfish ( Capros aper ) muscle protein hydrolysate was generated using the enzymes Alcalase 2.4 L and Flavourzyme 500 L. Furthermore, the BPH was subjected to simulated gastrointestinal digestion ( SGID ). BPH and SGID samples (0.01–2.5 mg mL −1 ) were tested in vitro for DPP ‐ IV inhibition and insulin and GLP ‐1 secretory activity from BRIN ‐ BD 11 and GLUT ag cells, respectively. The BPH and SGID samples, caused a dose‐dependent increase (4.2 to 5.3‐fold, P < 0.001) in insulin secretion from BRIN ‐ BD 11 cells and inhibited DPP ‐ IV activity ( IC 50 1.18 ± 0.04 and 1.21 ± 0.04 mg mL −1 ), respectively. The SGID sample produced a 1.3‐fold ( P < 0.01) increase in GLP ‐1 secretion. An oral glucose tolerance test ( OGTT ) was conducted in healthy mice ( n = 8), with or without BPH (50 mg/kg bodyweight). BPH mediated an increase in plasma insulin levels ( AUC (0–120 min), P < 0.05) and a consequent reduction in blood glucose concentration ( P < 0.01), after OGTT in mice versus controls. The BPH showed potent anti‐diabetic actions in cells and improved glucose tolerance in mice.