Active Peptides from Crayfish Shell: Isolation, Purification, Identification and Cytoprotective Function on Cells...

This study presents a strategy to develop crayfish shell peptides with enhanced antioxidant and angiotensin-I-converting enzyme (ACE) inhibitory properties. Crayfish shell protein hydrolysates (CSPH1-3) with different molecular weights were analyzed. CSPH2 (3-5 kDa) exhibited the strongest antioxidant activities, which could scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the 2,2'-azobis(3-ethylbenzothiazoline-6-sulfonic acid) sodium salt (ABTS) radical by (77.40 ± 4.54)% and (91.59 ± 0.30)%, respectively, and ACE inhibition activity of (64.74 ± 0.64)%. CSPH2 was further separated into three fractions, and CSPHF2 showed the maximum biological activity. The sequences of the purified antioxidant peptide (APAPLPPPAP) and ACE inhibitory peptide (QGPDDPLIPIM) were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in CSPHF2. These peptides increased the nitric oxide (NO) concentration and decreased the endothelin-1 (ET-1) content in human umbilical vein endothelial cells (HUVECs) in a dose-dependent manner, while also inhibiting reactive oxygen species (ROS). In addition, CSPH showed protective effects in terms of oxidative damage to HepG2 cells induced by H₂O₂. These findings suggest that crayfish shell peptides have potential applications as ingredients in antihypertensive agents and antioxidants, offering significant health benefits when consumed.