Current understanding of transport and bioavailability of bioactive peptides derived from dairy proteins: a review

Digestion of whey peptide induces antioxidant and anti-inflammatory bioactivity on glial cells: Sequences identification and structural activity analysis

Whey derived peptides have shown potential activity improving brain function in pathological condition. However, there is little information about their mechanism of action on glial cells, which have important immune functions in brain. Astrocytes and microglia are essential in inflammatory and oxidative defense that take place in neurodegenerative disease. In this work we evaluate antioxidant and anti-inflammatory potential bioactivity of whey peptide in glial cells. Peptides were formed during simulated gastrointestinal digestion (Infogest protocol), and low molecular weight (<5kDA) peptides (WPHf) attenuated reactive oxygen species (ROS) production induced by hydrogen peroxide stimulus in both cells in dose-dependent manner. WPHf induced an increase in the antioxidant glutathione (GSH) content and prevented GSH reduction induced by lipopolysaccharides (LPS) stimulus in astrocytes cells in a cell specific form. An increase in cytokine mRNA expression (TNFα and IL6) and nitric oxide secretion induced by LPS was attenuated by WPHf pre-treatment in both cells. The inflammatory pathway was dependent on NFκB activation. Bioactive peptide ranking analysis showed positive correlation with hydrophobicity and negative correlation with high molecular weights. The sequence identification revealed 19 peptides cross-referred with bioactive database. Whey peptides were rich in leucine, valine and tyrosine in the C-terminal region and lysine in the N-terminal region. The anti-inflammatory and antioxidant potential of whey peptides were assessed in glia cells and its mechanisms of action were related, such as modulation of antioxidant enzymes and anti-inflammatory pathways. Features of the peptide structure, such as molecular size, hydrophobicity and types of amino acids present in the terminal region are associated to bioactivity.

Glutamine-derived peptides: Current progress and future directions

Glutamine, the most abundant amino acid in the body, plays a critical role in preserving immune function, nitrogen balance, intestinal integrity, and resistance to infection. However, its limited solubility and instability present challenges for its use a functional nutrient. Consequently, there is a preference for utilizing glutamine-derived peptides as an alternative to achieve enhanced functionality. This article aims to review the applications of glutamine monomers in clinical, sports, and enteral nutrition. It compares the functional effectiveness of monomers and glutamine-derived peptides and provides a comprehensive assessment of glutamine-derived peptides in terms of their classification, preparation, mechanism of absorption, and biological activity. Furthermore, this study explores the potential integration of artificial intelligence (AI)-based peptidomics and synthetic biology in the de novo design and large-scale production of these peptides. The findings reveal that glutamine-derived peptides possess significant structure-related bioactivities, with the smaller molecular weight fraction serving as the primary active ingredient. These peptides possess the ability to promote intestinal homeostasis, exert hypotensive and hypoglycemic effects, and display antioxidant properties. However, our understanding of the structure-function relationships of glutamine-derived peptides remains largely exploratory at current stage. The combination of AI based peptidomics and synthetic biology presents an opportunity to explore the untapped resources of glutamine-derived peptides as functional food ingredients. Additionally, the utilization and bioavailability of these peptides can be enhanced through the use of delivery systems in vivo. This review serves as a valuable reference for future investigations of and developments in the discovery, functional validation, and biomanufacturing of glutamine-derived peptides in food science.

Metabolic Syndrome and Biotherapeutic Activity of Dairy (Cow and Buffalo) Milk Proteins and Peptides: Fast Food-Induced Obesity Perspective-A Narrative Review

Metabolic syndrome (MS) is defined by the outcome of interconnected metabolic factors that directly increase the prevalence of obesity and other metabolic diseases. Currently, obesity is considered one of the most relevant topics of discussion because an epidemic heave of the incidence of obesity in both developing and underdeveloped countries has been reached. According to the World Obesity Atlas 2023 report, 38% of the world population are presently either obese or overweight. One of the causes of obesity is an imbalance of energy intake and energy expenditure, where nutritional imbalance due to consumption of high-calorie fast foods play a pivotal role. The dynamic interactions among different risk factors of obesity are highly complex; however, the underpinnings of hyperglycemia and dyslipidemia for obesity incidence are recognized. Fast foods, primarily composed of soluble carbohydrates, non-nutritive artificial sweeteners, saturated fats, and complexes of macronutrients (protein-carbohydrate, starch-lipid, starch-lipid-protein) provide high metabolic calories. Several experimental studies have pointed out that dairy proteins and peptides may modulate the activities of risk factors of obesity. To justify the results precisely, peptides from dairy milk proteins were synthesized under in vitro conditions and their contributions to biomarkers of obesity were assessed. Comprehensive information about the impact of proteins and peptides from dairy milks on fast food-induced obesity is presented in this narrative review article.

Alterations in the sequence and bioactivity of food-derived oligopeptides during simulated gastrointestinal digestion and absorption: a review

Food-derived oligopeptides (FOPs) exhibit various bioactivities. However, little was known about their sequence changes in the gastrointestinal tract and the effect of changes on bioactivities. FOPs' sequence features, changes and effects on bioactivities have been summarised. The sequence length of FOPs decreases with increased exposure of hydrophobic and basic amino acids at the terminal during simulated gastrointestinal digestion. A decrease in bioactivities after simulated intestinal absorption has correlated with a decrease of Leu, Ile, Arg, Tyr, Gln and Pro. The sequence of FOPs that pass readily through the intestinal epithelium corresponds to transport modes, and FOPs whose sequences remain unchanged after transport are the most bioactive. These include mainly dipeptides to tetrapeptides, consisting of numerous hydrophobic and basic amino acids, found mostly at the end of the peptide chain, especially at the C-terminal. This review aims to provide a foundation for applications of FOPs in nutritional supplements and functional foods.

Olive (Olea europaea L.) Seed as New Source of Cholesterol-Lowering Bioactive Peptides: Elucidation of Their Mechanism of Action in HepG2 Cells and Their Trans-Epithelial Transport in Differentiated Caco-2 Cells

The production of olive oil has important economic repercussions in Mediterranean countries but also a considerable impact on the environment. This production generates enormous quantities of waste and by-products, which can be exploited as new raw materials to obtain innovative ingredients and therefore make the olive production more sustainable. In a previous study, we decided to foster olive seeds by generating two protein hydrolysates using food-grade enzymes, alcalase (AH) and papain (PH). These hydrolysates have shown, both in vitro and at the cellular level, antioxidant and antidiabetic activities, being able to inhibit the activity of the DPP-IV enzyme and modulate the secretion of GLP-1. Given the multifunctional behavior of peptides, both hydrolysates displayed dual hypocholesterolemic activity, inhibiting the activity of HMGCoAR and impairing the PPI of PCSK9/LDLR, with an IC50 equal to 0.61 mg/mL and 0.31 mg/mL for AH and PH, respectively. Furthermore, both samples restored LDLR protein levels on the membrane of human hepatic HepG2 cells, increasing the uptake of LDL from the extracellular environment. Since intestinal bioavailability is a key component of bioactive peptides, the second objective of this work is to evaluate the capacity of AH and PH peptides to be transported by differentiated human intestinal Caco-2 cells. The peptides transported by intestinal cells have been analyzed using mass spectrometry analysis, identifying a mixture of stable peptides that may represent new ingredients with multifunctional qualities for the development of nutraceuticals and functional foods to delay the onset of metabolic syndrome, promoting the principles of environmental sustainability.

Effects of Walnut and Pumpkin on Selective Neurophenotypes of Autism Spectrum Disorders: A Case Study

Special diets or nutritional supplements are regularly given to treat children with autism spectrum disorder (ASD). The increased consumption of particular foods has been demonstrated in numerous trials to lessen autism-related symptoms and comorbidities. A case study on a boy with moderate autism who significantly improved after three years of following a healthy diet consisting of pumpkin and walnuts was examined in this review in connection to a few different neurophenotypes of ASD. We are able to suggest that a diet high in pumpkin and walnuts was useful in improving the clinical presentation of the ASD case evaluated by reducing oxidative stress, neuroinflammation, glutamate excitotoxicity, mitochondrial dysfunction, and altered gut microbiota, all of which are etiological variables. Using illustrated figures, a full description of the ways by which a diet high in pumpkin and nuts could assist the included case is offered.

Potential of Food Protein-Derived Bioactive Peptides against Sarcopenia: A Comprehensive Review

Sarcopenia is an age-related progressive muscle disorder characterized by accelerated loss of muscle mass, strength, and function, which are important causes of physiological dysfunctions in the elderly. At present, the main alleviating method includes protein supplements to stimulate synthesis of muscle proteins. Food protein-derived peptides containing abundant branched-chain amino acids have a remarkable effect on the improvement of sarcopenia. Understanding the underlying molecular mechanism and clarifying the structure-activity relationship is essential for the mitigation of sarcopenia. This present review recaps the epidemiology, pathogenesis, diagnosis, and treatment of sarcopenia, which facilitates a comprehensive understanding of sarcopenia. Moreover, the latest research progress on food-derived antisarcopenic peptides is reviewed, including their antisarcopenic activity, molecular mechanism as well as structural characteristics. Food-derived bioactive peptides can indeed alleviate/mitigate sarcopenia. These antisarcopenic peptides play a pivotal role mainly by activating the PI3K/Akt/mTOR and MAPK pathways and inhibiting the ubiquitin-proteasome system and AMPK pathway, thus promoting the synthesis of muscle proteins and inhibiting their degradation. Antisarcopenic peptides alleviate sarcopenia via specific peptides, which may be absorbed into the circulation and exhibit their bioactivity in intact forms. The present review provides a theoretical reference for mitigation and prevention of sarcopenia by food protein-derived bioactive peptides.

Loss of bioactive microRNAs in cow's milk by ultra-high-temperature treatment but not by pasteurization treatment

BACKGROUND

Milk microRNA (miRNA) with bioactivity is beneficial for human health. However, the effect of heat treatment on miRNA in milk is still not clear. In this study, the miRNAs in raw (RM), pasteurized (PM) and ultra-high-temperature (UHT) milk (UM) from the same batch were extracted, sequenced and analyzed.

RESULTS

The results showed that there was a significant difference in miRNAs between RM and UM, but not between RM and PM. The total read counts of milk miRNAs were significantly decreased by heat treatment, with the least counts in UM (P < 0.05). The average length and GC percentage of miRNAs were significantly reduced by heat treatment (P < 0.05), while there was no significant difference in these terms between RM and PM. The content of miRNAs was verified by qPCR, finding that miR-17-5p, miR-25, miR-27b and miR-9-5p were significantly reduced in UM (P < 0.05) but not significantly affected in PM (except miR-27b). In addition, the targeting gene ontology enrichment functions of the different presented miRNAs were mostly enriched in biological process, cellular component and molecular function. The top 20 enriched miRNAs with different levels in heat-treated milk were identified by the Kyoto Encyclopedia of Genes and Genomes enrichment analysis. Interestingly, most of the functions of these miRNA targeting genes are involved in cancer or inflammation activity.

CONCLUSION

This study revealed that the bioactive miRNA in RM was lost after UHT treatment but not in pasteurized treatment. © 2021 Society of Chemical Industry.

A Novel Angiotensin I-Converting Enzyme Inhibitory Peptide Derived From Goat Milk Casein Hydrolysate Modulates Angiotensin II-Stimulated Effects on Vascular Smooth Muscle Cells

Hypertension is a major risk factor leading to cardiovascular disease, and is frequently treated with angiotensin I-converting enzyme (ACE) inhibitory peptides. The objective of this study was to separate and identify an ACE-inhibitory peptide from goat milk casein hydrolysates, and to evaluate its potential for improving angiotensin II (Ang II)-mediated adverse effects on vascular smooth muscle cells (VSMCs). A novel ACE-inhibitory peptide with the highest activity from the goat milk casein hydrolysates as determined by four steps of RP-HPLC was purified and identified as Phe-Pro-Gln-Tyr-Leu-Gln-Tyr-Pro-Tyr (FPQYLQYPY). The results of inhibitory kinetics studies indicated that the peptide was a non-competitive inhibitor against ACE. Gastrointestinal digest in vitro analysis showed that the hydrolysate of FPQYLQYPY was still active after digestion with gastrointestinal proteases. Moreover, we found that the peptide could significantly inhibit the proliferation and migration of Ang II-stimulated VSMCs. Further transcriptomic analysis revealed that differentially expressed genes (DEGs) were enriched in the cardiovascular disease-related pathways, and that the peptide may have the ability to regulate vascular remodeling. Our findings indicate the potential anti-hypertensive effects of FPQYLQYPY, as well-implicate its role in regulating vascular dysfunction.

Investigation of the intestinal trans-epithelial transport and antioxidant activity of two hempseed peptides WVSPLAGRT (H2) and IGFLIIWV (H3)

A preceding paper has shown that a hempseed peptic hydrolysate displays a cholesterol-lowering activity with a statin-like mechanism of action in HepG2 cells and a potential hypoglycemic activity by the inhibition of dipeptidyl peptidase-IV in Caco-2 cells. In the framework of a research aimed at fostering the multifunctional behavior of hempseed peptides, we present here the identification and evaluation of some antioxidant peptides from the same hydrolysate. After evaluation of its diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, a trans-epithelial transport experiment was performed using differentiated Caco-2 cells that permitted the identification of five transported peptides that were synthesized and evaluated by measuring the oxygen radical absorbance capacity (ORAC), the ferric reducing antioxidant power (FRAP), and the 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), and diphenyl-2-picrylhydrazyl radical DPPH assays. The most active peptides, i.e. WVSPLAGRT (H2) and IGFLIIWV (H3), were then tested in cell assays. Both peptides were able to reduce the H₂O₂-induced reactive oxygen species (ROS), lipid peroxidation, and nitric oxide (NO) production levels in HepG2 cells, via the modulation of Nrf-2 and iNOS pathways, respectively.

Current findings support the potential use of bioactive peptides in enhancing zinc absorption in humans

More than two billion people around the world are affected by zinc deficiency, mainly due to the inadequate intake and absorption of zinc. Based on recent research findings, the bioactive peptides could potentially be used to combat zinc deficiency particularly due to their Zinc chelating ability. The main aim of this review was to present current findings, supporting the potential use of bioactive peptides based on their ability to enhance zinc absorption. In-vivo, in-vitro, and ex-vivo studies have demonstrated that zinc chelating peptides can enhance the retention, transportation, and absorption of zinc. Comparative studies on zinc bioavailability from protein hydrolysates and zinc salts have demonstrated that the protein hydrolysates-zinc complexes are more bioavailable than the zinc salts. Data from the structure-function relationship of zinc chelating peptides suggest that the zinc chelating capacities of peptides increase in the following order; the position of zinc chelator > zinc chelator strength > abundance of zinc chelators > net charge > molecular weight. In addition, the transport mechanism of peptide-zinc complex is hypothesized, and the potential use of bioactive peptides based on their safety and taste and limitations to their commercialization are also discussed.

Identification and Screening of Potential Bioactive Peptides with Sleep-Enhancing Effects in Bovine Milk Casein Hydrolysate

Casein tryptic hydrolysate (CTH) has been proven to possess stress-relieving and sleep-enhancing effects, but only one decapeptide YLGYLEQLLR (α-CZP) in CTH was reported to exhibit affinity for the benzodiazepine site of a GABA_A receptor (GABA_AR). This study aimed to compare the sleep-enhancing effects between CTH and α-CZP and to explore novel sleep-enhancing peptides. Our results showed that CTH significantly prolonged sleep duration in mice, which was almost 2-fold longer than that of α-CZP. The α-CZP in CTH was degraded more slowly than the synthetic α-CZP; meanwhile, CTH could release other potential sleep-enhancing peptides during gastrointestinal digestion. Additionally, two peptides YPVEPF and YFYPEL with strong sleep-enhancing activity were explored by virtual screening. Especially, YPVEPF could significantly prolong the sleep duration from 559.00 ± 272.24 to 2501.63 ± 1021.21 s and increase the sleep rate from 58.33 to 83.33% in mice. Moreover, YPVEPF and YFYPEL could bind with the Ser-205 and Phe-77 residues of GABA_AR via hydrogen bonds and lipid contacts. They were largely released after digestion with 11.19 ± 0.15 and 1.78 ± 0.01 g/kg, respectively.

Viral 3CLpro as a Target for Antiviral Intervention Using Milk-Derived Bioactive Peptides

Viruses of the picornavirus-like supercluster mainly achieve cleavage of polyproteins into mature proteins through viral 3-chymotrypsin proteases (3C^pro) or 3-chymotrypsin-like proteases (3CL^pro). Due to the essential role in processing viral polyproteins, 3C^pro/3CL^pro is a drug target for treating viral infections. The 3CL^pro is considered the main protease (M^pro) of coronaviruses. In the current study, the SARS-CoV-2 M^pro inhibitory activity of di- and tri-peptides (DTPs) resulted from the proteolysis of bovine milk proteins was evaluated. A set of 326 DTPs were obtained from virtual digestion of bovine milk major proteins. The resulted DTPs were screened using molecular docking. Twenty peptides (P1–P20) showed the best binding energies (ΔG_b <  − 7.0 kcal/mol). Among these 20 peptides, the top five ligands, namely P1 (RVY), P3 (QSW), P17 (DAY), P18 (QSA), and P20 (RNA), based on the highest binding affinity and the highest number of interactions with residues in the active site of M^pro were selected for further characterization by ADME/Tox analyses. For further validation of our results, molecular dynamics simulation was carried out for P3 as one of the most favorable candidates for up to 100 ns. In comparison to N3, a peptidomimetic control inhibitor, high stability was observed as supported by the calculated binding energy of the M^pro-P3 complex (− 59.48 ± 4.87 kcal/mol). Strong interactions between P3 and the M^pro active site, including four major hydrogen bonds to HIS41, ASN142, GLU166, GLN189 residues, and many hydrophobic interactions from which the interaction with CYS145 as a catalytic residue is worth mentioning. Conclusively, milk-derived bioactive peptides, especially the top five selected peptides P1, P3, P17, P18, and P20, show promise as an antiviral lead compound.

Roles of Dietary Bioactive Peptides in Redox Balance and Metabolic Disorders

Bioactive peptides (BPs) are fragments of 2-15 amino acid residues with biological properties. Dietary BPs derived from milk, egg, fish, soybean, corn, rice, quinoa, wheat, oat, potato, common bean, spirulina, and mussel are reported to possess beneficial effects on redox balance and metabolic disorders (obesity, diabetes, hypertension, and inflammatory bowel diseases (IBD)). Peptide length, sequence, and composition significantly affected the bioactive properties of dietary BPs. Numerous studies have demonstrated that various dietary protein-derived BPs exhibited biological activities through the modulation of various molecular mechanisms and signaling pathways, including Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2/antioxidant response element in oxidative stress; peroxisome proliferator-activated-γ, CCAAT/enhancer-binding protein-α, and sterol regulatory element binding protein 1 in obesity; insulin receptor substrate-1/phosphatidylinositol 3-kinase/protein kinase B and AMP-activated protein kinase in diabetes; angiotensin-converting enzyme inhibition in hypertension; and mitogen-activated protein kinase and nuclear factor-kappa B in IBD. This review focuses on the action of molecular mechanisms of dietary BPs and provides novel insights in the maintenance of redox balance and metabolic diseases of human.

Dietary Bioactive Peptide Alanyl-Glutamine Attenuates Dextran Sodium Sulfate-Induced Colitis by Modulating Gut Microbiota

Inflammatory bowel disease (IBD) is a chronic intestinal disorder threatening human health. Di-peptide alanyl-glutamine (Ala-Gln) has various beneficial effects on gut health. However, its role and functional mechanism in treating IBD are still not clear. Therefore, the protective effects of Ala-Gln and glutamine (Gln) on dextran sulfate sodium- (DSS-) induced colitic mice were investigated in this study. The results showed that oral supplementation of Ala-Gln or Gln significantly attenuated the colitis symptoms in mice, including body weight loss, colon length, disease activity index, histological scores, and tissue apoptosis. The concentrations of interleukin- (IL-) 1β, IL-6, tumor necrosis factor-α, and myeloperoxidase were significantly decreased, while the concentrations of immunoglobulins (IgA, IgG, and IgM) and superoxide dismutase were significantly increased by Ala-Gln or Gln supplementation. The expression of occludin and peptide transporter 1 (PepT1) was significantly increased by Ala-Gln or Gln. Interestingly, Ala-Gln had better beneficial effects than Gln in alleviating colitis. In addition, 16S rDNA sequencing showed that the DSS-induced shifts of the microbiome (community diversity, evenness, richness, and composition) in the mouse colon were restored by Gln and Ala-Gln, including Lactobacillus, Bacteroides_acidifaciens, Bacteroidales, Firmicutes, Clostridia, Helicobacter, and Bacteroides. Correspondingly, the functions of the microflora metabolism pathways were also rescued by Ala-Gln, including fatty acid metabolism, membrane transporters, infectious diseases, and immune system. In conclusion, the results revealed that Ala-Gln can prevent colitis through PepT1, enhancing the intestinal barrier and modulating gut microbiota and microflora metabolites.

Potential of green and roasted coffee beans and spent coffee grounds to provide bioactive peptides

Protein extracts from green and roasted coffee beans and from spent coffee grounds (SCG) were evaluated as bioactive peptides sources. The in silico approach revealed a high frequency of the occurrence (A) of dipeptidyl peptidase-IV (DPP-IV) (0.62) and angiotensin I-converting enzyme (ACE) inhibitor peptides (0.44) in the 11S coffee globulin, which could be released after digestion. After in vitro digestion of the protein, the green bean and SCG proteins were more susceptible to proteolysis, releasing smaller polypeptides (3.4 kDa), which showed higher anti-hypertensive potentials (IC₅₀ = 0.30 and 0.27 mg soluble protein/mL). However, the antioxidant capacity only increased for the roasted coffee and SCG extracts due to antioxidant groups formed during roasting. The heat treatment applied during coffee brewing increased the sensitivity of the SCG extract to proteolysis, leading to their high anti-hypertensive and antioxidant potentials. Therefore, the 11S coffee globulin is a precursor of a series of bioactive peptides.

NoPv1: a synthetic antimicrobial peptide aptamer targeting the causal agents of grapevine downy mildew and potato late blight

Grapevine (Vitis vinifera L.) is a crop of major economic importance. However, grapevine yield is guaranteed by the massive use of pesticides to counteract pathogen infections. Under temperate-humid climate conditions, downy mildew is a primary threat for viticulture. Downy mildew is caused by the biotrophic oomycete Plasmopara viticola Berl. & de Toni, which can attack grapevine green tissues. In lack of treatments and with favourable weather conditions, downy mildew can devastate up to 75% of grape cultivation in one season and weaken newly born shoots, causing serious economic losses. Nevertheless, the repeated and massive use of some fungicides can lead to environmental pollution, negative impact on non-targeted organisms, development of resistance, residual toxicity and can foster human health concerns. In this manuscript, we provide an innovative approach to obtain specific pathogen protection for plants. By using the yeast two-hybrid approach and the P. viticola cellulose synthase 2 (PvCesA2), as target enzyme, we screened a combinatorial 8 amino acid peptide library with the aim to identify interacting peptides, potentially able to inhibit PvCesa2. Here, we demonstrate that the NoPv1 peptide aptamer prevents P. viticola germ tube formation and grapevine leaf infection without affecting the growth of non-target organisms and without being toxic for human cells. Furthermore, NoPv1 is also able to counteract Phytophthora infestans growth, the causal agent of late blight in potato and tomato, possibly as a consequence of the high amino acid sequence similarity between P. viticola and P. infestans cellulose synthase enzymes.

The Influence of Peptidases in Intestinal Brush Border Membranes on the Absorption of Oligopeptides from Whey Protein Hydrolysate: An Ex Vivo Study Using an Ussing Chamber

For many years, it was believed that only amino acids, dipeptides, and tripeptides could be absorbed and thus reach the bloodstream. Nowadays, the bioavailability of oligopeptides is also considered possible, leading to new research. This pilot study investigates the activity of brush border enzymes on undigested whey protein hydrolysate (WPH) and on simulated intestinal digested (ID) whey hydrolysate and the subsequent absorption of resultant peptides through the proximal jejunum of a 7-week old piglet setup in an Ussing chamber model. Amongst all samples taken, 884 oligopeptides were identified. The brush border peptidase activity was intense in the first 10 min of the experiment, producing several new peptides in the apical compartment. With respect to the ID substrate, 286 peptides were detected in the basolateral compartment after 120 min of enzyme activity, originating from β-lactoglobulin (60%) and β-casein (20%). Nevertheless, only 0.6 to 3.35% of any specific peptide could pass through the epithelial barrier and thus reach the basolateral compartment. This study demonstrates transepithelial jejunum absorption of whey oligopeptides in an ex vivo model. It also confirmed the proteolytic activity of brush border enzymes on these oligopeptides, giving birth to a myriad of new bioactive peptides available for absorption.

Identification of octopus peptide and its promotion of β-casein synthesis in a mouse mammary epithelial cell line

Octopus protein hydrolysate has been reported to increase milk yield and milk protein production. In this paper, the utilization and underlying mechanisms of bioactive peptide fractions from octopus protein hydrolysate on β-casein expression in mouse mammary epithelial cells (HC11) were investigated. Fraction OPH3-1 significantly stimulated cell proliferation and β-casein synthesis in HC11 cells, which was purified by ultra-filtration and gel-filtration chromatography. The MWs of the peptides from OPH3-1 ranged from 525-2,578 Da and consisted of 7-26 amino acid residues. Most of the peptides demonstrated the typical characteristics of milk protein synthesis promotion, especially MGLAGPR, MGDVLNF, EAPLMHV, and TEAPLMHV. Additionally, the mRNA abundances of mTOR, S6K1, 4EBP1, JAK2, and STAT5 were significantly enhanced by OPH3-1, which was consistent with the increased β-casein expression. These results suggest that the OPH3-1 peptides can promote the proliferation of mammary epithelial cells and increase β-casein synthesis. PRACTICAL APPLICATIONS: Breastfeeding mothers are generally recommended to take octopus soup as a daily diet to promote lactation. The peptides fraction OPH3-1 from the enzymatic hydrolysate of Octopus vulgaris which was revealed to significantly stimulate mammary epithelial cell proliferation and β-casein synthesis was obtained. This study suggests that octopus peptides can be used as nutritional supplements to increase the quantity and quality of milk production.

The Potential of Food Protein-Derived Bioactive Peptides against Chronic Intestinal Inflammation

Inflammation can cause various chronic diseases like inflammatory bowel diseases. Various food protein-derived bioactive peptides (BAPs) with anti-inflammatory activity have the potential to manage these diseases. The aim of this paper is to overview the mechanisms and the molecular targets of BAPs to exert anti-inflammatory activity. In this review, the in vitro and in vivo effects of BAPs on intestinal inflammation are highlighted. The mechanism, pathways, and future perspectives of BAPs as the potential sources of therapeutic treatments to alleviate intestinal inflammation are provided, including nuclear factor-κB, mitogen-activated protein kinase, Janus kinase-signal transducer and activator of transcription, and peptide transporter 1 (PepT1), finding that PepT1 and gut microbiota are the promising targets for BAPs to alleviate the intestinal inflammation. This review provides a comprehensive understanding of the role of dietary BAPs in attenuating inflammation and gives a novel direction in nutraceuticals for people or animals with intestinal inflammation.

Metabolic Syndrome-Preventive Peptides Derived from Milk Proteins and Their Presence in Cheeses: A Review

The metabolic syndrome (MetS) is defined as the occurrence of diet-related diseases such as abdominal obesity, atherogenic dyslipidemia, hyperglycemia (insulin resistance) and hypertension. Milk-derived peptides are well-known agents acting against high blood pressure, blood glucose level, and lipoprotein disproportion. The aim of this review are metabolic syndrome-preventive peptides derived from milk proteins which were identified in cheeses. Special attention was paid to the sequences acting as angiotensin converting enzyme (ACE), dipeptidyl peptidase IV (DDP4), and α-glucosidase inhibitors, as well as antioxidative, hypocholesterolemic, antiobesity, and anti-inflammatory agents. Some results of meta-analyses concerning the consumption of cheese and the risk of MetS diseases were also presented.