Purification and characterization of multifunctional peptides with in situ insulinotropic and antioxidative activity from a blue whiting ( Micromesistius poutassou ) protein hydrolysate

Two blue whiting protein hydrolysates (BWPHs) with potent in situ and in vitro antidiabetic and antioxidant activities were fractionated. Potent fractions were analysed using LC-MS/MS. Peptides VPVE and IPQD exhibited potent in situ DPP-IV inhibitory activity (Caco -2 cells) with IC 50 values of 88.79 +/- 5.40 and 91.12 +/- 19.73 mu M, respectively. Significant decreases in ROS production observed (HepG2 cells) with MPKKE, GPAG and MPAH. MPAH and LPDDL significantly (p < 0.05) increased intracellular glutathione (GSH) concentration (150.22 and 155.80 %, respectively). MPAH (196.05 %), GPSQ (183.26 %), MPKKE (153.12 %), SPEELK (152.85 %), GPAG (144.66 %), and LPDDI (142.74 %) significantly (p < 0.05) increased intracellular catalase (CAT) activity in comparison to control. Significant increases (p < 0.05) in superoxide dismutase (SOD) activity were observed following treatment with IPDDL (118.69 %), SPEEIK (118.03 %), LPDDI (117.20 %) and APEEHTP (116.60 %). The results indicate that blue whiting-derived peptides may have potential applications as multifunctional health enhancing ingredients with a focus on glycaemic management and antioxidant activity.