Preparation of Antioxidant Peptide by Microwave- Assisted Hydrolysis of Collagen and Its Protective Effect Against H2O2-Induced Damage of RAW264.7 Cells

New Insights into Antioxidant Peptides: An Overview of Efficient Screening, Evaluation Models, Molecular Mechanisms, and Applications

Antioxidant peptides are currently a hotspot in food science, pharmaceuticals, and cosmetics. In different fields, the screening, activity evaluation, mechanisms, and applications of antioxidant peptides are the pivotal areas of research. Among these topics, the efficient screening of antioxidant peptides stands at the forefront of cutting-edge research. To this end, efficient screening with novel technologies has significantly accelerated the research process, gradually replacing the traditional approach. After the novel antioxidant peptides are screened and identified, a time-consuming activity evaluation is another indispensable procedure, especially in in vivo models. Cellular and rodent models have been widely used for activity evaluation, whilst non-rodent models provide an efficient solution, even with the potential for high-throughput screening. Meanwhile, further research of molecular mechanisms can elucidate the essence underlying the activity, which is related to several signaling pathways, including Keap1-Nrf2/ARE, mitochondria-dependent apoptosis, TGF-β/SMAD, AMPK/SIRT1/PGC-1α, PI3K/Akt/mTOR, and NF-κB. Last but not least, antioxidant peptides have broad applications in food manufacture, therapy, and the cosmetics industry, which requires a systematic review. This review introduces novel technologies for the efficient screening of antioxidant peptides, categorized with a new vision. A wide range of activity evaluation assays, encompassing cellular models, as well as rodent and non-rodent models, are provided in a comprehensive manner. In addition, recent advances in molecular mechanisms are analyzed with specific cases. Finally, the applications of antioxidant peptides in food production, therapy, and cosmetics are systematically reviewed.

Research progress on the chemical components and biological activities of sea cucumber polypeptides

Owing to their unique physical and chemical properties and remarkable biological activities, marine biological resources are emerging as important sources of raw materials for producing health products, food, and cosmetics. Collagen accounts for approximately 70% of the sea cucumber body wall, and its hydrolysis produces small-molecule collagen polypeptides with diverse biological functions, such as anticancer, antihypertensive, immune-enhancing, memory-enhancing, and cartilage tissue repairing effects. Notably, the potential of sea cucumber polypeptides in combination with anticancer therapy has garnered considerable attention. Determining the composition and structure of sea cucumber polypeptides and exploring their structure-activity relationships will aid in obtaining an in-depth understanding of their diverse biological activities and provide scientific insights for the development and utilization of these polypeptides. Therefore, this review focuses on the amino acid structures and activities of sea cucumber polypeptides of varying molecular weights. This study also provides an overview of the biological activities of various sea cucumber polypeptides and aims to establish a scientific basis for their development.

Antioxidant Peptides from the Collagen of Antler Ossified Tissue and Their Protective Effects against H2O2-Induced Oxidative Damage toward HaCaT Cells

Antler ossified tissue has been widely used for the extraction of bioactive peptides. In this study, collagen was prepared from antler ossified tissue via acetic acid and pepsin. Five different proteases were used to hydrolyze the collagen and the hydrolysate treated by neutrase (collagen peptide named ACP) showed the highest DPPH radical clearance rate. The extraction process of ACP was optimized by response surface methodology, and the optimal conditions were as follows: a temperature of 52 °C, a pH of 6.1, and an enzyme concentration of 3200 U/g, which resulted in the maximum DPPH clearance rate of 74.41 ± 0.48%. The peptides (ACP-3) with the strongest antioxidant activity were obtained after isolation and purification, and its DPPH free radical clearance rate was 90.58 ± 1.27%; at the same time, it exhibited good scavenging activity for ABTS, hydroxyl radical, and superoxide anion radical. The study investigated the protective effect of ACP-3 on oxidative damage in HaCaT cells. The findings revealed that all groups that received ACP-3 pretreatment exhibited increased activities of SOD, GSH-Px, and CAT compared to the model group. Furthermore, ACP-3 pretreatment reduced the levels of ROS and MDA in HaCaT cells subjected to H2O2-induced oxidative damage. These results suggest that collagen peptides derived from deer antler ossified tissue can effectively mitigate the oxidative damage caused by H2O2 in HaCaT cells, thereby providing a foundation for the utilization of collagen peptides in pharmaceuticals and cosmetics.

Antioxidant peptides: Overview of production, properties, and applications in food systems

In recent years, several studies have reported the beneficial effects of antioxidant peptides in delaying oxidation reactions. Thus, a growing number of food proteins have been investigated as suitable sources for obtaining these antioxidant peptides. In this study, some of the most critical developments in the discovery of peptidic antioxidants are discussed. Initially, the primary methods to release, purify, and identify these antioxidant peptides from various food-derived sources are reviewed. Then, computer-based screening methods of the available peptides are summarized, and methods to interpret their structure-activity relationship are illustrated. Finally, approaches to the large-scale production of these bioactive peptides are described. In addition, the applications of these antioxidants in food systems are discussed, and gaps, future challenges, and opportunities in this field are highlighted. In conclusion, various food items can be considered promising sources to obtain these novel antioxidant peptides, which present various opportunities for food applications in addition to health promotion. The lack of in-depth data on the link between the structure and activity of these antioxidants, which is critical for the prediction of possible bioactive amino acid sequences and their potency in food systems and in vivo conditions (rather than in vitro systems), requires further attention. Consequently, future collaborative research activities between the industry and academia are required to realize the commercialization objectives of these novel antioxidant peptides.

Enhancing osteogenic potential of hDPSCs by resveratrol through reducing oxidative stress via the Sirt1/Nrf2 pathway

CONTEXT

The osteogenic potential of the human dental pulp stromal cells (hDPSCs) was reduced in the state of oxidative stress. Resveratrol (RSV) possesses numerous biological properties, including osteogenic potential, growth-promoting and antioxidant activities.

OBJECTIVE

This study investigates the osteogenic potential of RSV by activating the Sirt1/Nrf2 pathway on oxidatively stressed hDPSCs and old mice.

MATERIALS AND METHODS

The hDPSCs were subjected to reactive oxygen species (ROS) fluorescence staining, cell proliferation assay, ROS activity assay, superoxide dismutase (SOD) enzyme activity, the glutathione (GSH) concentration assay, alkaline phosphatase staining, real-time polymerase chain reaction (RT-PCR) and Sirt1 immunofluorescence labelling to assess the antioxidant stress and osteogenic ability of RSV. Forty female Kunming mice were divided into Old, Old-RSV, Young and Young-RSV groups to assess the repair of calvarial defects of 0.2 mL RSV of 20 mg/kg/d for seven days by injecting intraperitoneally at 4 weeks after surgery using micro-computed tomography, nonlinear optical microscope and immunohistochemical analysis.

RESULTS

RSV abates oxidative stress by alleviating the proliferation, mitigating the ROS activity, increasing the SOD enzyme activity and ameliorating the GSH concentration (RSV IC₅₀ in hDPSCs is 67.65 ± 9.86). The antioxidative stress and osteogenic capabilities of RSV were confirmed by the up-regulated gene expression of SOD1, xCT, RUNX2 and OCN, as well as Sirt1/Nrf2. The collagen, bone matrix formation and Sirt1 expression, are significantly increased after RSV treatment in mice.

DISCUSSION AND CONCLUSIONS

For elderly or patients with oxidative stress physiological states such as hypertension, heart disease, diabetes, etc., RSV may potentially improve bone augmentation surgery in regenerative medicine.

Peptide profiles and antioxidant capacity of extensive hydrolysates of milk protein concentrate

Milk protein concentrate was hydrolyzed using one-step enzymatic hydrolysis. Both the peptide profiles and antioxidant activities of the resulting extensive hydrolysates of milk protein concentrate (EMPH) were analyzed using a peptidomics approach based on liquid chromatography-tandem mass spectrometry. The results demonstrated that the degrees of hydrolysis of the 4 EMPH by Alcalase-Protamex, Alcalase-Protease A 2SD, Alcalase-Flavorzyme, and Alcalase-ProteAXH were 12.02%, 16.85%, 15.87%, and 15.77%, respectively. Using size exclusion chromatography, 99.85% of the peptides in the Alcalase-Protease A 2SD hydrolysate were shown to have a molecular weight of <3 kDa. A total of 33 common peptides were identified in the EMPH by liquid chromatography-tandem mass spectrometry, 16 of which were identified as bioactive peptides using bioinformatics. The peptide profiles and the coverage of master proteins of the 4 EMPH were different. The EMPH also exhibited strong free radical scavenging capacity, as indicated by the results of the 1,1-diphenyl-2-picrylhydrazyl radical, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), hydroxyl radical, and reducing power assays. The results of this study provided useful information on the peptide profiles and antioxidant activity of EMPH.

Physicochemical Properties of Collagen from the Bone of Harpadon nehereus and Its Protective Effects against Angiotensin II-Induced Injury in Human Umbilical Vein Endothelial Cells

The physicochemical characterization of a new collagen from the bone of Harpadon nehereus (HNBC) and its protective effects against Ang II-induced injury of human umbilical vein endothelial cells (HUVEC) were investigated. The triple helix of HNBC analyzed by SDS-PAGE was formed as (α₁)₂α₂, belonging to type I collagen. UV spectra showed that HNBC had a maximum absorbance at 230 nm. FTIR spectra indicated the triple helical structure and activity of HNBC. The high solubility of HNBC was observed in the low pH ranges (≤4) and NaCl concentrations (≤2%, w/v). The maximum transition (T _m) of HNBC was determined to be 48.5 °C. The amino acid composition analysis showed that glycine, glutamic acid, proline, and alanine were the abundant amino acids available in HNBC. HNBC showed free radical (DPPH and OH·) scavenging activities in the tested concentrations (0.5-6 mg/mL). In addition, HNBC could effectively protect against Ang II-induced injury of HUVEC by increasing the activities of antioxidant enzymes, such as CAT, SOD, and GSH-Px. Overall, collagen from the bone of H. nehereus has promising prospects in functional food and biomedical industries.

Production of Bioactive Peptides from Sea Cucumber and Its Potential Health Benefits: A Comprehensive Review

Bioactive peptides from food have been widely studied due to their potential applications as functional foods and pharmaceuticals. Sea cucumber, a traditional tonic food, is characterized by high protein and low fat, thereby substrates are being studied to release sea cucumber peptides (SCPs). Although recent studies have shown that SCPs have various bioactive functions, there is no literature reviewing the development status of SCPs. In this review, we summarized the production of SCPs, including their purification and identification, then mainly focused on the comprehensive potential health benefits of SCP in vivo and in vitro, and finally discussed the challenge facing the development of SCPs. We found that SCPs have well-documented health benefits due to their antioxidation, anti-diabetes, ACE inhibitory, immunomodulatory, anti-cancer, anti-fatigue, anti-aging, neuroprotection, micromineral-chelating, etc. However, the structure-activity relationships of SCPs and the functional molecular mechanisms underlying their regulation in vivo need further investigation. Research on the safety of SCP and its potential regulation mechanism will contribute to transferring these findings into commercial applications. Hopefully, this review could promote the development and application of SCPs in further investigation and commercialization.

Conventional and Novel Technologies in the Production of Dairy Bioactive Peptides

Background

In recent years, researchers have focused on functional ingredients, functional foods, and nutraceuticals due to the rapidly increasing interest in bioactive components, especially in bioactive peptides. Dairy proteins are a rich and balanced source of amino acids and their derived bioactive peptides, which possess biological and physiological properties. In the dairy industry, microbial fermentation and enzymatic hydrolysis are promising methods for producing bioactive peptides because of their rapid efficiency, and mild reaction conditions. However, these methods utilize less raw material, take long reaction time, result in low yields, and low activity products when used alone, which pose industry to seek for novel methods as pretreatments to increase the yield of bioactive peptides.

Scope and Approach

This review emphasizes the production of peptides from the dairy proteins and discusses the potential use of novel technologies as pretreatments to conventional methods of bioactive peptides production from dairy proteins, including the mechanisms of novel technologies along with respective examples of use, advantages, limitations, and challenges to each technology.

Key Findings and Conclusion

Noteworthily, hydrolysis of dairy proteins liberate wide-range of peptides that possess remarkable biological functions to maintain human health. Novel technologies in the dairy industry such as ultrasound-assisted processing (UAP), microwave-assisted processing (MAP), and high pressure processing (HPP) are innovative and environmentally friendly. Generally, novel technologies are less effectual compared to conventional methods, therefore used in combination with fermentation and enzymatic hydrolysis, and are promising pretreatments to modify peptides’ profile, improve the yields, and high liberation of bioactive peptides as compared to conventional technologies. UAP is an innovative and most efficient technology as its mechanical effects and cavitation change the protein conformation, increase the biological activities of enzymes, and enhance enzymatic hydrolysis reaction rate.

Novel Antioxidant Collagen Peptides of Siberian Sturgeon (Acipenser baerii) Cartilages: The Preparation, Characterization, and Cytoprotection of H2O2-Damaged Human Umbilical Vein Endothelial Cells (HUVECs)

For making full use of aquatic by-products to produce high value-added products, Siberian sturgeon (Acipenser baerii) cartilages were degreased, mineralized, and separately hydrolyzed by five kinds of proteases. The collagen hydrolysate (SCH) generated by Alcalase showed the strongest 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·) and hydroxide radical (HO·) scavenging activity. Subsequently, thirteen antioxidant peptides (SCP1-SCP3) were isolated from SCH, and they were identified as GPTGED, GEPGEQ, GPEGPAG, VPPQD, GLEDHA, GDRGAEG, PRGFRGPV, GEYGFE, GFIGFNG, PSVSLT, IELFPGLP, LRGEAGL, and RGEPGL with molecular weights of 574.55, 615.60, 583.60, 554.60, 640.64, 660.64, 885.04, 700.70, 710.79, 602.67, 942.12, 714.82, and 627.70 Da, respectively. GEYGFE, PSVSLT, and IELFPGLP showed the highest scavenging activity on DPPH· (EC₅₀: 1.27, 1.05, and 1.38 mg/mL, respectively) and HO· (EC₅₀: 1.16, 0.97, and 1.63 mg/mL, respectively), inhibiting capability of lipid peroxidation, and protective functions on H₂O₂-damaged plasmid DNA. More importantly, GEYGFE, PSVSLT, and IELFPGLP displayed significant cytoprotection on HUVECs against H₂O₂ injury by regulating the endogenous antioxidant enzymes of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) to decrease the contents of reactive oxygen species (ROS) and malondialdehyde (MDA). Therefore, the research provided better technical assistance for a higher-value utilization of Siberian sturgeon cartilages and the thirteen isolated peptides—especially GEYGFE, PSVSLT, and IELFPGLP—which may serve as antioxidant additives for generating health-prone products to treat chronic diseases caused by oxidative stress.

Preventive Effect of Collagen Peptides from Acaudina molpadioides on Acute Kidney Injury through Attenuation of Oxidative Stress and Inflammation

The protective effect of collagen peptide from Acaudina molpadioides (Amp) on acute kidney injury (AKI) in mice and its mechanism were explored. The results showed that Amp-fed could effectively improve the renal mass index and histopathological morphology. The levels of serum creatinine and urea nitrogen decreased significantly, while the antioxidant enzyme catalase (CAT) and superoxide dismutase (SOD) increased significantly in Amp-fed groups. Western blot results disclosed that Amp significantly upregulates the levels of heme oxygenase-1 (HO-1), Nrf2, p-PI3K, and p-AKT in the kidney. In addition, Amp could significantly downregulate the levels of nuclear factor NF-kappa-B (NF-κB), tumor necrosis factor α (TNF-α), inflammatory cytokines interleukin 6 (IL-6) and interleukin 1β (IL-1β). These findings provide evidence that Amp plays a protective role in AKI via attenuation of oxidative stress and inflammation mediated by PI3K/AKT/Nrf2 and PI3K/AKT/NF-κB pathways. This study laid a foundation for the application of Amp in the prevention of AKI.

Extraction and Identification of Three New Urechis unicinctus Visceral Peptides and Their Antioxidant Activity

The viscera of Urechis unicinctus with polypeptides, fatty acids, and amino acids are usually discarded during processing to food. In order to improve the utilization value of the viscera of Urechis unicinctus and avoid resource waste, antioxidant polypeptides were isolated from the viscera of Urechis unicinctus. First, a protein hydrolysate of Urechis unicinctus (UUPH) was prepared by ultrasonic-assisted enzymatic hydrolysis, and the degree of hydrolysis was as high as 79.32%. Subsequently, three new antioxidant peptides (P1, P2, and P3) were purified from UUPH using ultrafiltration and chromatography, and their amino acid sequences were identified as VTSALVGPR, IGLGDEGLRR, TKIRNEISDLNER, respectively. Then, the antioxidant activity of the polypeptide was predicted by the structure-activity relationship and finally verified by experiments on eukaryotic cells. The P1 peptide exhibited the strongest antioxidant activity among these three antioxidant peptides. Furthermore, P1, P2, and P3 have no toxic effect on RAW264.7 cells at the concentration of 0.01~2 mg/mL and can protect RAW264.7 cells from H2O2-induced oxidative damage in a concentration-dependent manner. These results suggested that these three new antioxidant peptides were isolated from the viscera of Urechis unicinctus, especially the P1 peptide, which might serve as potential antioxidants applied in health-derived food or beverages. This study further developed a new use of the by-product of Urechis unicinctus, which improved the comprehensive utilization of marine biological resources.

Bioactive fish collagen peptides weaken intestinal inflammation by orienting colonic macrophages phenotype through mannose receptor activation

PURPOSE

Particular interest is now given to the potential of dietary supplements as alternative non-pharmacological approaches in intestinal inflammation handling. In this aim, this study evaluates the efficiency of fish collagen peptides, Naticol^®Gut, on colonic inflammation.

METHODS

Wild type and Mannose receptor-deficient in the myeloid lineage C57BL/6 mice were administered with Dextran Sodium Sulfate (DSS), Naticol^®Gut, DSS, and Naticol^®Gut or only water for 4 or 8 days. Inflammatory status was evaluated by establishing macroscopic and microscopic scores, by measuring cytokine and calprotectin production by ELISA and the myeloperoxidase activity by chemiluminescence. Colonic macrophages were phenotyped by measuring mRNA levels of specific markers of inflammation and oxidative status. Colonic immune populations and T-cell activation profiles were determined by flow cytometry. Mucosa-associated gut microbiota assessment was undertaken by qPCR. The phenotype of human blood monocytes from inflammatory bowel disease (IBD) subjects was characterized by RT-qPCR and flow cytometry and their oxidative activity by chemiluminescence.

RESULTS

Naticol^®Gut-treated DSS mice showed attenuated colonic inflammation compared to mice that were only exposed to DSS. Naticol^®Gut activity was displayed through its ability to orient the polarization of colonic macrophage towards an anti-inflammatory and anti-oxidant phenotype after its recognition by the mannose receptor. Subsequently, Naticol^®Gut delivery modulated CD4 T cells in favor of a Th2 response and dampened CD8 T-cell activation. This immunomodulation resulted in an intestinal eubiosis. In human monocytes from IBD subjects, the treatment with Naticol^®Gut also restored an anti-inflammatory and anti-oxidant phenotype.

CONCLUSION

Naticol^®Gut acts as a protective agent against colitis appearing as a new functional food and an innovative and complementary approach in gut health.

Enzymatic Hydrolysis of Broken Rice Protein: Antioxidant Activities by Chemical and Cellular Antioxidant Methods

Excessive reactive oxygen species (ROS) is an important cause of aging, and supplementing antioxidants through diet is one of the important ways to delay aging. Some studies have confirmed that rice protease hydrolysate has antioxidant activity, but was rarely been investigated on cells. Thus, commercial enzymes, alkaline enzyme, neutral enzyme, pepsin, chymotrypsin, and trypsin were selected to hydrolyze broken rice protein (BRP) to obtain the corresponding hydrolysates, which were A-broken rice protein hydrolysate (BRPH), N-BRPH, P-BRPH, C-BRPH, and T-BRPH, respectively. Then the antioxidant properties of BRPHs were evaluated by different chemical and cellular antioxidation. Molecular weight, peptide length distribution, and amino acid sequence were detected to insight into the antioxidant properties. Among BRPHs, the A-BRPH displayed the strongest hydroxyl radical scavenging activity (IC50 = 1.159 mg/ml) and metal ion-chelating activities (IC50 = 0.391 mg/ml). Furthermore, cellular antioxidation confirmed that A-BRPH significantly increased cell viability and inhibited the intracellular ROS release in both aging cells and cell-aging processes. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results revealed that peptides with molecular weight <14.5 KDa were produced by enzymatic hydrolysis. Additionally, A-BRPH rich in low molecular weight (<3 kDa) and short-length peptides with some specific amino acids, such as aromatic and hydrophobic amino acids, contributes to the antioxidant properties. This study provided theoretical to the utilization of broken rice and confirmed that A-BRPH could be used in new anti-aging food and health products for human consumption.

A Review on the Extraction and Processing of Natural Source-Derived Proteins through Eco-Innovative Approaches

In addition to their nutritional and physiological role, proteins are recognized as the major compounds responsible for the rheological properties of food products and their stability during manufacture and storage. Furthermore, proteins have been shown to be source of bioactive peptides able to exert beneficial effects on human health. In recent years, scholarly interest has focused on the incorporation of high-quality proteins into the diet. This fact, together with the new trends of consumers directed to avoid the intake of animal proteins, has boosted the search for novel and sustainable protein sources and the development of suitable, cost-affordable, and environmentally friendly technologies to extract high concentrations of valuable proteins incorporated into food products and supplements. In this review, current data on emergent and promising methodologies applied for the extraction of proteins from natural sources are summarized. Moreover, the advantages and disadvantages of these novel methods, compared with conventional methods, are detailed. Additionally, this work describes the combination of these technologies with the enzymatic hydrolysis of extracted proteins as a powerful strategy for releasing bioactive peptides.

Antioxidant Mechanisms of the Oligopeptides (FWKVV and FMPLH) from Muscle Hydrolysate of Miiuy Croaker against Oxidative Damage of HUVECs

In this work, the antioxidant mechanisms of bioactive oligopeptides (FWKVV and FMPLH) from protein hydrolysate of miiuy croaker muscle against H₂O₂-damaged human umbilical vein endothelial cells (HUVECs) were researched systemically. The finding demonstrated that the HUVEC viability treated with ten antioxidant peptides (M1 to M10) at 100.0 μM for 24 h was not significantly affected compared with that of the normal group (P < 0.05). Furthermore, FWKVV and FMPLH at 100.0 μM could very significantly enhance the viabilities (75.89 ± 1.79% and 70.03 ± 4.37%) of oxidative-damaged HUVECs by H₂O₂ compared with those of the model group (51.66 ± 2.48%) (P < 0.001). The results indicated that FWKVV and FMPLH played their protective functions through increasing the levels of antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreasing the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and nitric oxide (NO) in oxidative-damaged HUVECs in a dose-dependent manner. In addition, the comet assay revealed that FWKVV and FMPLH could dose-dependently protect deoxyribonucleic acid (DNA) from oxidative damage in the HUVEC model. These results suggested that antioxidant pentapeptides (FWKVV and FMPLH) could serve as potential antioxidant additives applied in the food products, pharmaceuticals, and health supplements.

Effect of two-step enzymatic hydrolysis on the antioxidant properties and proteomics of hydrolysates of milk protein concentrate

Food protein and peptides are generally considered a source of dietary antioxidants. The antioxidant activity and peptide profiles of four extensive hydrolysates of milk protein concentrate (MPC) were examined using the two-step enzymatic method. The hydrolysis combinations were Alcalase-Flavourzyme (AE), Alcalase-ProteAXH (AH), Alcalase-Protamex (AX) and Alcalase-Protease A 2SD (AD). The results showed that highest degree of hydrolysis corresponded to the AE sample (20.41%). High-efficiency gel-filtration chromatography results indicated that the relative proportions of extensive hydrolysates with molecular weights < 3 kDa were 99.89%, 99.57%, 99.93%, and 99.89% for AX, AE, AD and AH, respectively. The hydrolysates of the MPC exhibited increased radical-scavenging capacity, as evidenced through an analysis with 1,1-diphenyl-2-pycryl-hydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazo-line-6-sulfonic acid) diammonium salt (ABTS), reducing power and hydroxyl-radical scavenging activity testing. The main bioactive peptides were identified through EASY-nLC-orbitrap MS/MS and bioinformatics. The study may provide useful information regarding the antioxidant properties of extensive hydrolysates of MPC.

Cytoprotective Effects of Fish Protein Hydrolysates against H2O2-Induced Oxidative Stress and Mycotoxins in Caco-2/TC7 Cells

Many studies report the potent antioxidant capacity for fish protein hydrolysates, including radical scavenging activity and inhibition ability on lipid peroxidation (LPO). In this study, the in vitro cytotoxicity of protein hydrolysates from different salmon, mackerel, and herring side streams fractions was evaluated in the concentration range from 1 to 1:32 dilution, using cloned human colon adenocarcinoma cells TC7 (Caco-2/TC7) by MTT and PT assays. The protein hydrolysates' antioxidant capacity and oxidative stress effects were evaluated by LPO and reactive oxygen species (ROS) generation, respectively. The antioxidant capacity for pure and bioavailable hydrolysate fraction was also evaluated and compared. Additionally, mycotoxin levels were determined in the fish protein hydrolysates, and their cytoprotective effect against T-2 toxin was evaluated. Both hydrolysates and their bioavailable fraction induced similar cell viability rates. The highest cytoprotective effect was obtained for the salmon viscera protein hydrolysate (HSV), which increased the cell viability by 51.2%. ROS accumulation induced by H₂O₂ and LPO was suppressed by all pure hydrolysates. The cytoprotective effect of hydrolysates was observed against T-2. Moreover, the different fish fraction protein hydrolysates contain variable nutrients and unique bioactive peptide composition showing variable bioactivity, which could be a useful tool in developing dietary supplements with different target functional properties.

Regulation of H2O2-induced cells injury through Nrf2 signaling pathway: An introduction of a novel cysteic acid-modified peptide

A novel peptide (Cya-Phe-Leu-Ala-Pro, SCP) was formulated through non-protein amino acid-cysteic acid (Cya) modification of collagen peptide (Phe-Leu-Ala-Pro, CP) from Acaudina molpadioides. Introduction of this Cya showed remarkable improvement in the scavenging activities of OH·. SCP exhibited stronger effects than CP in preventing H₂O₂-induced oxidative damage due to lower levels of ROS and MDA, and higher activities of antioxidant enzymes, such as SOD, GSH-Px, HO-1, and NQO1. It was speculated that SCP could significantly increase the expression level of Nrf2 compared to CP, thereby activating the expression of downstream ARE genes. The expression levels of p38 in the upstream pathway to regulate Nrf2 content were significantly higher in both the CP and SCP-treated groups, while a higher level of JNK was observed only in the SCP-treated groups. The present study provided insights towards the application of cysteic acid modified peptide in protecting cell from oxidative damage through the JNK/Nrf2 pathway.

Optimization of Extraction of Bioactive Peptides from Monkfish (Lophius litulon) and Characterization of Their Role in H2O2-Induced Lesion

Background: Marine fish meat has been widely used for the extraction of bioactive peptides. This study was aimed to optimize the preparation of monkfish muscle peptides (LPs) using response surface methodology (RSM) and explore the antioxidant activities of <1 kDa LPs. Methods: Peptides were prepared from the muscles of monkfish (Lophius litulon), and five proteases were tested to hydrolyze muscle proteins. The hydrolysate that was treated using neutrase showed the highest degree of hydrolysis (DH) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activities. Results: The optimized conditions were as follows: water/material ratio of 5.4:1, a time span of 5 h, pH of 7.0, enzyme concentration of 2000 U/g, and temperature of 45 °C; the maximum DPPH scavenging activity and DH were 92.861% and 19.302%, respectively. LPs exhibited appreciable antioxidant activities, including DPPH radical, hydroxyl radical, 2,2′-azinobis-3-ethylbenzthiazoline-6-sulphonate (ABTS) radical, and superoxide anion scavenging activities. LPs attenuated H₂O₂-related oxidative injury in RAW264.7 cells, reduced the reactive oxygen species (ROS) and malondialdehyde (MDA) levels, and increased the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) levels. Conclusion: We concluded that LPs could be an ideal source of bioactive peptides from monkfish and also have pharmaceutical potential.

Advances on Food-Derived Peptidic Antioxidants-A Review

The oxidation process is considered to be the main reason behind human aging, human degenerative diseases and food quality degradation. Food-derived peptidic antioxidants (PAs) have wide sources and great activity, and have broad application prospects in removing excess reactive oxygen species in the body, anti-aging and preventing and treating diseases related to oxidative stress. On the other hand, PAs are expected to inhibit the lipid peroxidation of foods and increase the stability of the food system in the food industry. However, the production pathways and action mechanism of food-derived PAs are diverse, which makes it is difficult to evaluate the performance of PAs which is why the commercial application of PAs is still in its infancy. This article focuses on reviewing the preparation, purification, and characterization methods of food-derived PAs, and expounds the latest progress in performance evaluation and potential applications, in order to provide an effective reference for subsequent related research of PAs.

Collagen Peptides from Swim Bladders of Giant Croaker (Nibea japonica) and Their Protective Effects against H2O2-Induced Oxidative Damage toward Human Umbilical Vein Endothelial Cells

Five different proteases were used to hydrolyze the swim bladders of Nibea japonica and the hydrolysate treated by neutrase (collagen peptide named SNNHs) showed the highest DPPH radical scavenging activity. The extraction process of SNNHs was optimized by response surface methodology, and the optimal conditions were as follows: a temperature of 47.2 °C, a pH of 7.3 and an enzyme concentration of 1100 U/g, which resulted in the maximum DPPH clearance rate of 95.44%. Peptides with a Mw of less than 1 kDa (SNNH-1) were obtained by ultrafiltration, and exhibited good scavenging activity for hydroxyl radicals, ABTS radicals and superoxide anion radicals. Furthermore, SNNH-1 significantly promoted the proliferation of HUVECs, and the protective effect of SNNH-1 against oxidative damage of H2O2-induced HUVECs was investigated. The results indicated that all groups receiving SNNH-1 pretreatment showed an increase in GSH-Px, SOD, and CAT activities compared with the model group. In addition, SNNH-1 pretreatment reduced the levels of ROS and MDA in HUVECs with H2O2-induced oxidative damage. These results indicate that collagen peptides from swim bladders of Nibea japonica can significantly reduce the oxidative stress damage caused by H2O2 in HUVECs and provides a basis for the application of collagen peptides in the food industry, pharmaceuticals, and cosmetics.

Physicochemical Properties of Collagen from Acaudina Molpadioides and Its Protective Effects against H2O2-Induced Injury in RAW264.7 Cells

Collagen is a promising biomaterial used in the beauty and biomedical industries. In this study, the physicochemical characterization, antioxidant activities, and protective effects against H₂O₂-induced injury of collagen isolated from Acaudina molpadioides were investigated. The amino acid composition analysis showed that the collagen was rich in glycine (Gly), alanine (Ala), and glutamic acid (Glu), but poor in tyrosine (Tyr) and phenylalanine (Phe). Zeta potential analysis revealed that the isoelectric point (pI) of collagen from Acaudina molpadioides was about 4.25. It possessed moderate scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals in a dose-dependent manner. In addition, the collagen was able to effectively improve cell viability and morphology, inhibit the production of Malondialdehyde (MDA), and increase the activities of Superoxide Dismutase (SOD) and Glutathione Peroxidase (GSH-Px) in cultured RAW264.7 cells, resulting in a protective effect against H₂O₂-induced injury. Overall, the results showed that collagen extracted from A. molpadioides has promising prospects in the beauty and cosmetics industries.