Octopus-derived antioxidant peptide protects against hydrogen peroxide-induced oxidative stress in IEC-6 cells

Advances in the application and mechanism of bioactive peptides in the treatment of inflammation

Inflammation is a normal immune response in organisms, but it often triggers chronic diseases such as colitis and arthritis. Currently, the most widely used anti-inflammatory drugs are non-steroidal anti-inflammatory drugs, albeit they are accompanied by various adverse effects such as hypertension and renal dysfunction. Bioactive peptides (BAPs) provide therapeutic benefits for inflammation and mitigate side effects. Herein, this review focuses on the therapeutic effects of various BAPs on inflammation in different body parts. Emphasis is placed on the immunomodulatory mechanisms of BAPs in treating inflammation, such as regulating the release of inflammatory mediators, modulating MAPK and NF-κB signaling pathways, and reducing oxidative stress reactions for immunomodulation. This review aims to provide a reference for the function, application, and anti-inflammation mechanisms of BAPs.

WeiNaiAn capsule attenuates intestinal mucosal injury and regulates gut microbiome in indomethacin-induced rat

Indomethacin, as a non-steroidal anti-inflammatory drugs, is widely used in the clinic. However, it can cause severe injury to the gastrointestinal tract and the incidence is increasing. It has become an essential clinical problem in preventing intestinal damage. Teprenone has been reported to have a significant positive effect on intestinal mucosal lesions, but long-term use of teprenone can elicit adverse reactions. WeiNaiAn capsule is a traditional Chinese medicine formulation used widely in the treatment of gastric and duodenal mucosal injury. However, how WeiNaiAn protects against intestinal mucosal injury and its mechanism of action are not known. In this study, WeiNaiAn capsule or Teprenone treatment improved the intestinal mucosal pathological score and antioxidant level in indomethacin-induced rats. 16 S rRNA sequence data showed WeiNaiAn capsule reverted the structure community and replenished the beneficial bacteria. Furthermore, fingerprint analysis revealed multiple components of WeiNaiAn capsule, including calycosin glucoside, ginsenoside Rg1, ginsenoside Rb1, taurocholic acid sodium, formonetin, and calycosin glucoside. The components of WeiNaiAn capsule promoted the wound healing of the epithelial cell in vitro. Moreover, the components of WeiNaiAn capsule inhibited the protein expressions of phosphoinositide 3-kinase /protein kinase B /mammalian target of rapamycin in hydrogen peroxide or lipopolysaccharides-induced cell model. In conclusion, WeiNaiAn capsule improves intestinal mucosal injury by regulating cell migration, enhancing antioxidant activity, and promoting the structure of the bacterial community homeostasis, the multiple targets provide the parameters for the treatment in the clinic.

Protective Effect of Peptides from Pinctada Martensii Meat on the H2O2-Induced Oxidative Injured HepG2 Cells

Pinctada martensii is a major marine pearl cultured species in southern China, and its meat is rich in protein, which is an excellent material for the preparation of bioactive peptides. In this study, the peptides from Pinctada martensii meat were prepared by simulated gastrointestinal hydrolysis, and after multistep purification, the structures of the peptides were identified, followed by the solid-phase synthesis of the potential antioxidant peptides. Finally, the antioxidant activities of the peptides were verified using HepG2 cells, whose oxidative stress was induced by hydrogen peroxide (H₂O₂). It was shown that the antioxidant peptide (S4) obtained from Pinctada martensii meat could significantly increase the cell viability of HepG2 cells. S4 could also scavenge reactive oxygen species (ROS) and reduce the lactate dehydrogenase (LDH) level. In addition, it could enhance the production of glutathione (GSH) and catalase (CAT) in HepG2 cells, as well as the expression of key genes in the Nrf2 signaling pathway. Three novel antioxidant peptides, arginine-leucine (RL), arginine-glycine-leucine (RGL), and proline-arginine (PR), were also identified. In conclusion, peptides from Pinctada martensii meat and three synthetic peptides (RGL, RL, PR) showed antioxidant activity and could have the potential to be used as antioxidant candidates in functional foods.

Octopus-derived antioxidant peptide protects against hydrogen peroxide-induced oxidative stress in IEC-6 cells

This study aims to find antioxidant peptides from octopus protein hydrolyzates and verify the protective effects against H2O2-induced oxidative stress in IEC-6 cells. After the alcalase hydrolysate was ultrafiltrated, purified by Sephadex G-25 gel fractionation and semipreparative reversed-phase high-performance liquid chromatography (RP-HPLC), 16 peptides were identified, and chemically synthesized. In particular, the peptides AQNY, AMMLAW, FEGAW, GGAW, VDTVVCVW, and VVCLW showed better oxygen radical absorbance capacity (ORAC) and ABTS radical scavenging capacity. Among them, the smallest-molecular-weight peptide GGAW exhibited the best antioxidant activity. Furthermore, GGAW protected IEC-6 cells from H2O2-induced oxidative damage by significantly reducing the generation of reactive oxygen species (ROS), malondialdehyde (MDA), and lactate dehydrogenase (LDH), and increasing the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), thereby improving cell viability. These results indicated that the peptide GGAW possessed the antioxidant capacity to prevent oxidative stress damage.