Purification and Identification of Antioxidant Peptides from Schizochytrium Limacinum Hydrolysates by Consecutive Chromatography and Electrospray Ionization-Mass Spectrometry

Identification and Molecular Mechanism of Anti-inflammatory Peptides Isolated from Jack Bean Protein Hydrolysates: in vitro Studies with Human Intestinal Caco-2BBe Cells

Jack bean (JB), Canavalia ensiformis (L.) DC, is a commonly cultivated legume in Indonesia. It is rich in protein, which can be hydrolyzed, making it potentially a good source of bioactive peptides. Intestinal inflammation is associated with several diseases, and the production of interleukin-8 (IL-8) in intestinal epithelial cells induced by tumor necrosis factor (TNF)-α has an important role in inflammatory reaction. The present study investigated the anti-inflammatory effects of peptides generated from enzymatic hydrolysis of JB protein on human intestinal Caco-2BBe cells. Additionally, in silico approaches were used to identify potential bioactive peptides. JB protein hydrolysate (JBPH) prepared using pepsin and pancreatin reduced the IL-8 expression at protein and mRNA levels in Caco-2BBe cells stimulated with TNF-α. Immunoblot analysis showed that the JBPH reduced the TNF-α-induced phosphorylation of c-Jun-NH(2)-terminal kinase, nuclear factor kappa B (NF-κB), and p38 proteins. Anti-inflammatory activity was observed in the 30% acetonitrile fraction of JBPH separated on a Sep-Pak C18 column. An ultrafiltration method revealed that relatively small peptides (< 3 kDa) had a potent inhibitory effect on the IL-8 production. Purification of the peptides by reversed-phase and anion-exchange high performance chromatography produced three peptide fractions with anti-inflammatory activities. A combination of mass spectrometry analysis and in silico approaches identified the potential anti-inflammatory peptides. Peptides derived from JB protein reduces the TNF-α-induced inflammatory response in Caco-2BBe cells via NF-κB and mitogen-activated protein kinase signaling pathways. Our results may lead to a novel therapeutic approach to promote intestinal health.

A novel peptide derived from Zingiber cassumunar rhizomes exhibits anticancer activity against the colon adenocarcinoma cells (Caco-2) via the induction of intrinsic apoptosis signaling

This paper presents the initial exploration of the free radical scavenging capabilities of peptides derived from protein hydrolysates (PPH) obtained from Zingiber cassumunar rhizomes (Phlai). To replicate the conditions of gastrointestinal digestion, a combination of pepsin and pancreatin proteolysis was employed to generate these hydrolysates. Subsequently, the hydrolysate underwent fractionation using molecular weight cut-off membranes at 10, 5, 3, and 0.65 kDa. The fraction with a molecular weight less than 0.65 kDa exhibited the highest levels ABTS, DPPH, FRAP, and NO radical scavenging activity. Following this, RP-HPLC was used to further separate the fraction with a molecular weight less than 0.65 kDa into three sub-fractions. Among these, the F5 sub-fraction displayed the most prominent radical-scavenging properties. De novo peptide sequencing via quadrupole-time-of-flight-electron spin induction-mass spectrometry identified a pair of novel peptides: Asp-Gly-Ile-Phe-Val-Leu-Asn-Tyr (DGIFVLNY or DY-8) and Ile-Pro-Thr-Asp-Glu-Lys (IPTDEK or IK-6). Database analysis confirmed various properties, including biological activity, toxicity, hydrophilicity, solubility, and potential allergy concerns. Furthermore, when tested on the human adenocarcinoma colon (Caco-2) cell line, two synthetic peptides demonstrated cellular antioxidant activity in a concentration-dependent manner. These peptides were also assessed using the FITC Annexin V apoptosis detection kit with PI, confirming the induction of apoptosis. Notably, the DY-8 peptide induced apoptosis, upregulated mRNA levels of caspase-3, -8, and -9, and downregulated Bcl-2, as confirmed by real-time quantitative polymerase chain reaction (RT-qPCR). Western blot analysis indicated increased pro-apoptotic Bax expression and decreased anti-apoptotic Bcl-2 expression in Caco-2 cells exposed to the DY-8 peptide. Molecular docking analysis revealed that the DY-8 peptide exhibited binding affinity with Bcl-2, Bcl-xL, and Mcl-1, suggesting potential utility in combating colon cancer as functional food ingredients.

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.

Acetylcholinesterase and butyrylcholinesterase inhibitory activities of antioxidant peptides obtained from enzymatic pea protein hydrolysates and their ultrafiltration peptide fractions

This study optimized the enzymatic hydrolysis of yellow field pea proteins using alcalase (ACH), chymotrypsin (CHH), flavourzyme (FZH), pancreatin (PCH), pepsin (PEH), and trypsin (TPH) to obtain hydrolysates and ultrafiltered fractions (<1, 1-3, 3-5 and 5-10 kDa) that possess antioxidant plus acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities. The hydrolysates exhibited varying degrees of radical scavenging and inhibition of linoleic acid peroxidation, as well as cholinesterase inhibition activities but the potency generally improved by >10% after UF separation into peptide fractions. ACH, FZH, and PEH exhibited significantly (p < .05) higher (20%-30% increases) radical scavenging activities than the other hydrolysates. The 1 and 3 kDa UF fractions of ACH, FZH, and PEH inhibited ~20%-30% AChE activity, while ACH, PCH, TPH, and PEH inhibited ~20%-40% BuChE activity. We conclude that the pea protein hydrolysates and their peptide fractions possess multifunctional properties with potential use against neurodegenerative disorders. PRACTICAL APPLICATIONS: Alzheimer's disease (AD) has multiple pathological pathways in addition to the loss of acetylcholine (ACh) catalyzed by acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The presence of severe oxidative stress triggered by lipid peroxidation and formation of free radicals is a common trait in AD patients. The concept of AChE and BuChE inhibition as an approach toward AD amelioration involves the use of compounds with a similar structure to ACh, the natural substrate. Peptides derived from food proteins consist of ester bonds with structural similarity to ACh and theoretically possess the ability to interact with AChE and BuChE. Results from the present study imply that pea protein-derived peptides are potential candidates for use as inhibitors of AChE and BuChE activities, with application in the prevention and management of AD.

Novel Antioxidant Peptides from Grateloupia livida Hydrolysates: Purification and Identification

Grateloupia livida protein was hydrolyzed with various proteases (alkaline protease, Protamex and neutral protease) to obtain anti-oxidative peptides. Antioxidant activity of the enzymatic hydrolysates was evaluated by the DPPH radical scavenging, ABTS radical scavenging and reducing power assays. The results suggested that hydrolysates obtained by neutral protease 1 h hydrolysis displayed the highest antioxidant activity (DPPH IC50 value of 3.96 mg/mL ± 0.41 mg/mL, ABTS IC50 value of 0.88 ± 0.13 mg/mL and reducing power of 0.531 ± 0.012 at 8 mg/mL), and had low molecular weight distribution (almost 99% below 3 kDa). Three fractions (F1-F3) were then isolated from the hydrolysates by using semi-preparative RP-HPLC, and the fraction F3 showed the highest antioxidant ability. Four antioxidant peptides were identified as LYEEMKESKVINADK, LEADNVGVVLMGDGR, LIDDSFGTDAPVPERL, and GLDELSEEDRLT from the F3 by LC-MS/MS. Online prediction showed that the four peptides possessed good water solubility, non-toxic and non-allergenic characteristics. Moreover, the LYEEMKESKVINADK exhibited the highest antioxidant ability. Molecular docking revealed that these peptides could all well bind with Kelch-like ECH-associated protein 1 (Keap1), among which LYEEMKESKVINADK had the lowest docking energy (-216.878 kcal/mol). These results demonstrated that the antioxidant peptides from Grateloupia livida could potentially be used as natural antioxidant.

Production and antioxidant capacity of bioactive peptides from plant biomass to counteract lipid oxidation

Preventing lipid oxidation, especially with the polyunsaturated fat-based products, is a major concern in sectors as agri-food and cosmetic. Even though the efficiency of synthetic antioxidants has been recognized, both consumers and manufacturers are looking for more innovative, healthy and quality products while rejecting synthetic additives due to their concern about safety, along with their environmental impact issues. In this context, plant biomass, which have shown to be rich in compounds, have raised interest for the isolation of novel naturally occurring antioxidants. Among their myriad of molecules, bioactive peptides, which are biologically active sequence of amino acid residues of proteins, seem to be of a great interest. Therefore, the number of identified amino acids sequences of bioactive peptides from plant biomass with potential antioxidant action is progressively increasing. Thus, this review provides a description of 129 works that have been made to produce bioactive peptides (hydrolysate, fraction and/or isolate peptide) from 55 plant biomass, along with the procedure to examine their antioxidant capacity (until 2019 included). The protein name, the process, and the method to concentrate or isolate antioxidant bioactive peptides, along with their identification and/or specificity were described. Considering the complex, dynamic and multifactorial physico-chemical mechanisms of the lipid oxidation, an appropriate in-vitro methodology should be better performed to efficiently probe the antioxidant potential of bioactive peptides. Therefore, the results were discussed, and perspective for antioxidant applications of bioactive peptides from plant biomass was argued.

Use of Alcalase in the production of bioactive peptides: A review

This review aims to cover the uses of the commercially available protease Alcalase in the production of biologically active peptides since 2010. Immobilization of Alcalase has also been reviewed, as immobilization of the enzyme may improve the final reaction design enabling the use of more drastic conditions and the reuse of the biocatalyst. That way, this review presents the production, via Alcalase hydrolysis of different proteins, of peptides with antioxidant, angiotensin I-converting enzyme inhibitory, metal binding, antidiabetic, anti-inflammatory and antimicrobial activities (among other bioactivities) and peptides that improve the functional, sensory and nutritional properties of foods. Alcalase has proved to be among the most efficient proteases for this goal, using different protein sources, being especially interesting the use of the protein residues from food industry as feedstock, as this also solves nature pollution problems. Very interestingly, the bioactivities of the protein hydrolysates further improved when Alcalase is used in a combined way with other proteases both in a sequential way or in a simultaneous hydrolysis (something that could be related to the concept of combi-enzymes), as the combination of proteases with different selectivities and specificities enable the production of a larger amount of peptides and of a smaller size.

Scientific Opinion on the update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA (2017-2019)

The qualified presumption of safety (QPS) was developed to provide a safety pre-assessment within EFSA for microorganisms. Strains belonging to QPS taxonomic units (TUs) still require an assessment based on a specific data package, but QPS status facilitates fast track evaluation. QPS TUs are unambiguously defined biological agents assessed for the body of knowledge, their safety and their end use. Safety concerns are, where possible, to be confirmed at strain or product level, and reflected as 'qualifications'. Qualifications need to be evaluated at strain level by the respective EFSA units. The lowest QPS TU is the species level for bacteria, yeasts and protists/algae, and the family for viruses. The QPS concept is also applicable to genetically modified microorganisms used for production purposes if the recipient strain qualifies for the QPS status, and if the genetic modification does not indicate a concern. Based on the actual body of knowledge and/or an ambiguous taxonomic position, the following TUs were excluded from the QPS assessment: filamentous fungi, oomycetes, streptomycetes, Enterococcus faecium, Escherichia coli and bacteriophages. The list of QPS-recommended biological agents was reviewed and updated in the current opinion and therefore now becomes the valid list. For this update, reports on the safety of previously assessed microorganisms, including bacteria, yeasts and viruses (the latter only when used for plant protection purposes) were reviewed, following an Extensive Literature Search strategy. All TUs previously recommended for 2016 QPS list had their status reconfirmed as well as their qualifications. The TUs related to the new notifications received since the 2016 QPS opinion was periodically evaluated for QPS status in the Statements of the BIOHAZ Panel, and the QPS list was also periodically updated. In total, 14 new TUs received a QPS status between 2017 and 2019: three yeasts, eight bacteria and three algae/protists.

Update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA 11: suitability of taxonomic units notified to EFSA until September 2019

Qualified presumption of safety (QPS) was developed to provide a generic safety evaluation for biological agents to support EFSA's Scientific Panels. The taxonomic identity, body of knowledge, safety concerns and antimicrobial resistance are assessed. Safety concerns identified for a taxonomic unit (TU) are where possible to be confirmed at strain or product level, reflected by 'qualifications'. No new information was found that would change the previously recommended QPS TUs and their qualifications. The list of microorganisms notified to EFSA was updated with 54 biological agents, received between April and September 2019; 23 already had QPS status, 14 were excluded from the QPS exercise (7 filamentous fungi, 6 Escherichia coli, Sphingomonas paucimobilis which was already evaluated). Seventeen, corresponding to 16 TUs, were evaluated for possible QPS status, fourteen of these for the first time, and Protaminobacter rubrum, evaluated previously, was excluded because it is not a valid species. Eight TUs are recommended for QPS status. Lactobacillus parafarraginis and Zygosaccharomyces rouxii are recommended to be included in the QPS list. Parageobacillus thermoglucosidasius and Paenibacillus illinoisensis can be recommended for the QPS list with the qualification 'for production purposes only' and absence of toxigenic potential. Bacillus velezensis can be recommended for the QPS list with the qualification 'absence of toxigenic potential and the absence of aminoglycoside production ability'. Cupriavidus necator, Aurantiochytrium limacinum and Tetraselmis chuii can be recommended for the QPS list with the qualification 'production purposes only'. Pantoea ananatis is not recommended for the QPS list due to lack of body of knowledge in relation to its pathogenicity potential for plants. Corynebacterium stationis, Hamamotoa singularis, Rhodococcus aetherivorans and Rhodococcus ruber cannot be recommended for the QPS list due to lack of body of knowledge. Kodamaea ohmeri cannot be recommended for the QPS list due to safety concerns.