Dipeptidyl peptidase IV inhibitory peptides generated in Spanish dry-cured ham

Bioactive peptides in dry-cured ham: A comprehensive review of preparation methods, metabolic stability, safety, health benefits, and regulatory frameworks

Dry-cured hams contain abundant bioactive peptides with significant potential for the development of functional foods. However, the limited bioavailability of food-derived bioactive peptides has hindered their utilization in health food development. Moreover, there is insufficient regulatory information regarding bioactive peptides and related products globally. This review summarizes diverse bioactive peptides derived from dry-cured ham and by-products originating from various countries and regions. The bioactivity, preparation techniques, bioavailability, and metabolic stability of these bioactive peptides are described, as well as the legal and regulatory frameworks in various countries. The primary objectives of this review are to dig deeper into the functionality of dry-cured ham and provide theoretical support for the commercialization of bioactive peptides from food sources, especially the dry-cured ham.

Identification, characterization, and insights into the mechanism of novel dipeptidyl peptidase-IV inhibitory peptides from yak hemoglobin by in silico exploration, molecular docking, and in vitro assessment

Dipeptidyl peptidase IV (DPP-IV) inhibitory peptides were screened and identified from yak hemoglobin for the first time by in silico analysis, molecular docking, and in vitro evaluation. Results showed that yak hemoglobin had a high potential to produce DPP-IV inhibitory peptides based on the sequence alignment and bioactive potential evaluation. Furthermore, "pancreatic elastase + stem bromelain" was the optimal combined-enzymatic strategy by simulated proteolysis. Additionally, 25 novel peptides were found from its simulated hydrolysate, among which 10 peptides had high binding affinities with DPP-IV by molecular docking. Most of these peptides were also in silico characterized with favorable physicochemical properties and biological potentials, including relatively low molecular weight, high hydrophobicity, several net charges, good water solubility, nontoxicity, acceptable sensory quality, and good human intestinal absorption. Finally, six novel DPP-IV inhibitory peptides were identified via in vitro assessment, among which EEKA (IC50 = 235.26 μM), DEV (IC50 = 339.45 μM), and HCDKL (IC50 = 632.93 μM) showed the strongest capacities. The hydrogen bonds and electrostatic attractions formed with core residues within the S2 pocket of DPP-IV could be mainly responsible for their inhibition performances. This work provided a time-saving method and broadened application for yak by-products development as sources of functional foods.

An Update on Dipeptidyl Peptidase-IV Inhibiting Peptides

Diabetes is a chronic metabolic disorder. According to the International Diabetes Federation, about 537 million people are living with diabetes. The two types of diabetes are type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM), among which the population affected by T2DM is relatively higher. A major reason for T2DM is that insulin stimulation is hampered due to the inactivation of incretin hormones. Dipeptidyl peptidase-IV (DPP-IV) is a serine protease that is directly involved in the inactivation of incretin hormones, e.g., glucagon-like peptide-1 (GLP-1). Therefore, the inhibition of DPP-IV can be a promising method for managing T2DM, in addition to other enzyme inhibition strategies, such as inhibition of α-amylase and α -glucosidase. Currently, about 12 different gliptin drugs are available in the market that inhibit DPP-IV in a dose-dependent manner. Instead of gliptins, 'peptides' can also be employed as an alternative and promising way to inhibit DPP-IV. Peptide inhibitors of DPP-IV have been identified from various plants and animals. Chemically synthesized peptides have also been experimented for inhibiting DPP-IV. Most peptides have been analysed by biochemical assays, whereas some in vitro assays have also been reported. Molecular docking analysis has been applied to comprehend the mechanism of inhibition. In this review, certain aspects of natural as well as synthetic peptides are described that have been proven to inhibit DPP-IV.

A review on bioactive peptides derived from meat and by-products: Extraction methods, biological activities, applications and limitations

Meat and its by-products offer a rich source of bioactive compounds which have potential applications in both the food and pharmaceutical industries. In this review, we present several extraction methods and report the identification and properties of bioactive peptides. We also examine the challenges and limitations associated with their use in food applications. Enzymatic hydrolysis and fermentation using starts cultures are common methods for generating bioactive peptides from meat proteins. Additionally, natural gastrointestinal digestion can also produce bioactive peptides. However, emerging technologies like high hydrostatic pressure, subcritical extraction and pulsed electric fields can improve hydrolysis and increase the yield of bioactive peptides. Online bioinformatics applications have emerged as an established method for identifying potentially bioactive peptides. These tools reduce the cost and time required for traditional methods of research. Finally, incorporating bioactive peptides into diets for specific purposes such as supporting vulnerable populations like children and the elderly ensures safety and efficacy.

Exploring the Potential of Black Soldier Fly Larval Proteins as Bioactive Peptide Sources through in Silico Gastrointestinal Proteolysis: A Cheminformatic Investigation

Despite their potential as a protein source for human consumption, the health benefits of black soldier fly larvae (BSFL) proteins following human gastrointestinal (GI) digestion are poorly understood. This computational study explored the potential of BSFL proteins to release health-promoting peptides after human GI digestion. Twenty-six proteins were virtually proteolyzed with GI proteases. The resultant peptides were screened for high GI absorption and non-toxicity. Shortlisted peptides were searched against the BIOPEP-UWM and Scopus databases to identify their bioactivities. The potential of the peptides as inhibitors of myeloperoxidase (MPO), NADPH oxidase (NOX), and xanthine oxidase (XO), as well as a disruptor of Keap1–Nrf2 protein–protein interaction, were predicted using molecular docking and dynamics simulation. Our results revealed that about 95% of the 5218 fragments generated from the proteolysis of BSFL proteins came from muscle proteins. Dipeptides comprised the largest group (about 25%) of fragments arising from each muscular protein. Screening of 1994 di- and tripeptides using SwissADME and STopTox tools revealed 65 unique sequences with high GI absorption and non-toxicity. A search of the databases identified 16 antioxidant peptides, 14 anti-angiotensin-converting enzyme peptides, and 17 anti-dipeptidyl peptidase IV peptides among these sequences. Results from molecular docking and dynamic simulation suggest that the dipeptide DF has the potential to inhibit Keap1–Nrf2 interaction and interact with MPO within a short time frame, whereas the dipeptide TF shows promise as an XO inhibitor. BSFL peptides were likely weak NOX inhibitors. Our in silico results suggest that upon GI digestion, BSFL proteins may yield high-GI-absorbed and non-toxic peptides with potential health benefits. This study is the first to investigate the bioactivity of peptides liberated from BSFL proteins following human GI digestion. Our findings provide a basis for further investigations into the potential use of BSFL proteins as a functional food ingredient with significant health benefits.

Influence of Pig Genetic Line and Salt Reduction on Peptide Production and Bioactivity of Dry-Cured Hams

Ham (Jamón) is a product of great value in Spanish gastronomy, although experts have recommended reducing its consumption due to its high salt content and its relationship with cardio-vascular diseases due to the increase in blood pressure it may cause. Therefore, the objective of this study was to evaluate how the reduction of salt content and the pig genetic line influence bioactivity in boneless hams. For this purpose, 54 hams were studied, 18 boneless Iberian hams (RIB), 18 boneless white hams from commercial cross-bred pigs (RWC), and 18 salted and traditionally processed Iberian hams (TIB) to check if the pig genetic line (RIB vs. RWC) or the processing (RIB vs. TIB) affect the peptide production and bioactivity of the hams. The pig genetic line significantly affected the activity of ACE-I and DPPH, with RWC having the highest ACE-I activity and RIB having the highest antioxidative activity. This coincides with the results obtained in the identification of the peptides and the bioactivity analysis performed. Salt reduction positively affected the different hams, influencing their proteolysis and increasing their bioactivity in traditionally cured hams.

DPP-IV Inhibitory Peptides GPF, IGL, and GGGW Obtained from Chicken Blood Hydrolysates

Blood is a meat by-product rich in proteins with properties that can be improved after hydrolysis, making it a sustainable alternative for use in the generation of bioactive peptides. The objective of this study was to identify dipeptidyl peptidase IV (DPP-IV) inhibitory peptides obtained from different chicken blood hydrolysates prepared using combinations of four different enzymes. Best results were observed for AP (2% Alcalase + 5% Protana Prime) and APP (2% Alcalase + 5% Protana Prime + 3% Protana UBoost) hydrolysates obtaining inhibition values of 60.55 and 53.61%, respectively, assayed at a concentration of 10 mg/mL. Free amino acids were determined to establish the impact of exopeptidase activity in the samples. A total of 79 and 12 sequences of peptides were identified by liquid chromatography and mass spectrometry in tandem (LC-MS/MS) in AP and APP samples, respectively. Nine of the identified peptides were established as potential DPP-IV inhibitory using in silico approaches and later synthesized for confirmation. Thus, peptides GPF, IGL, and GGGW showed good DPP-IV inhibitory activity with IC₅₀ values of 0.94, 2.22, and 2.73 mM, respectively. This study confirmed the potential of peptides obtained from chicken blood hydrolysates to be used as DPP-IV inhibitors and, therefore, in the control or modulation of type 2 diabetes.

Peptidomics as a useful tool in the follow-up of food bioactive peptides

There is an intense research activity on bioactive peptides derived from food proteins in view of their health benefits for consumers. However, their identification is quite challenging as a consequence of their small size and low abundance in complex matrices such as foods or hydrolyzates. Recent advances in peptidomics and bioinformatics are getting improved sensitivity and accuracy and therefore such tools are contributing to the development of sophisticated methodologies for the identification and quantification of peptides. These developments are very useful for the follow-up of peptides released through proteolysis either in the food itself through the action of endogenous peptidases during processing stages like fermentation, drying or ripening, or from food proteins hydrolyzed by commercial peptidases or microorganisms with proteolytic activity. This chapter is presenting the latest advances in peptidomics and its use for the identification and quantification of peptides, and as a useful tool for controlling the proteolysis phenomena in foods and protein hydrolyzates.

Investigating the Short Peptidome Profile of Italian Dry-Cured Ham at Different Processing Times by High-Resolution Mass Spectrometry and Chemometrics

Short peptides have been spiking interest owing to their significant contribution to the taste and functional properties of dry-cured ham. In this study, a suspect screening approach based on high-resolution mass spectrometry was employed for the comprehensive characterization of the short endogenous peptidome in dry-cured ham samples at different processing stages (14, 22, and 34 months). After careful manual spectra interpretation, a chemometric approach based on principal component analysis was employed for highlighting the differences between the three sets of samples. A total of 236 short peptide sequences was tentatively identified, including 173 natural short peptides and 63 sequences containing non-proteinogenic amino acids, the highest number ever reported for endogenous sequences in dry-cured ham. Samples in the latest processing stages presented a generally higher abundance of dipeptides, indicating residual proteolytic activity. Moreover, the several annotated modified short peptides, mainly pyroglutamination and lactoyl conjugation, allowed hypothesizing several reactions occurring over time. For the first time, several lactoyl-dipeptides were tentatively identified in dry-cured ham samples with maximum concentration in the late processing stage samples. The presented results significantly contribute to the understanding of the reaction involving short peptides that affect the sensory and functional properties of dry-cured ham.

Dipeptidyl Peptidase IV Inhibitory Peptides Generated in Dry-Cured Pork Loin during Aging and Gastrointestinal Digestion

The ability of peptides from an aqueous and salt-soluble protein extract of dry-cured pork loins to inhibit the action of dipeptidyl peptidase IV was determined. This activity was assessed at different times of the production process, i.e., 28, 90, 180, 270 and 360 days. The resistance of the biological property during the simulated digestive process was also assessed. For this, the extracts were hydrolyzed with pepsin and pancreatin as a simulated digestion step of the gastrointestinal tract and fractionated (>7 kDa) as an intestinal absorption step. The results indicate that dried-pork-loin peptides may have potential as functional food ingredients in the prevention and treatment of type 2 diabetes mellitus. In particular, the APPPPAEV, APPPPAEVH, KLPPLPL, RLPLLP, VATPPPPPPK, VPIPVPLPM and VPLPVPVPI sequences show promise as natural food compounds helpful in maintaining good health.

Purification, identification and molecular mechanism of dipeptidyl peptidase IV inhibitory peptides from discarded shrimp (Penaeus vannamei) head

DPP-IV plays a key role for regulation of glucose metabolism in the body. The object of this study was to obtain DPP-IV inhibitors from discarded but protein-rich Penaeus vannamei (P. vannamei) head, and to explore the potential mechanism between DPP-IV and its inhibitors. P. vannamei head protein was hydrolyzed by five food grade proteases, respectively. The animal protease hydrolysate showed the highest inhibitory active. Then the hydrolysate was sequentially separated by ultrafiltration, gel filtration chromatography and reversed phase high-performance liquid chromatography (RP-HPLC), the peptides sequences were identified by LC-MS/MS and four potential peptides YPGE, VPW, HPLY, YATP showed superior DPP-IV inhibitory activity. Meanwhile, molecular docking effectively explored their mechanism through formed hydrogen bonds and hydrophobic regions. The four peptides showed better DPP-IV inhibitory activity stability with heating treatment, pH (1-10) treatment, and in vitro gastrointestinal digestion. Our results demonstrated that the protein hydrolysate from discarded P. vannamei head can be considered as a promising natural source of DPP-IV inhibitor for helping to improve glycaemic control in Type 2 diabetes.

Trends in In Silico Approaches to the Prediction of Biologically Active Peptides in Meat and Meat Products as an Important Factor for Preventing Food-Related Chronic Diseases

The increasing awareness of modern consumers regarding the nutritional and health value of food has changed their preferences, as well their requirements, for food products, including meat and meat products. Expanding the knowledge on the impact of food on human health is currently one of the most important research areas for scientists worldwide, and it is also of interest to consumers who want to consciously compose their daily diets. New research methods, such as in silico techniques, offer solutions to these new challenges. These research methods are preferred over food evaluation, e.g., from meat, because of their advantages, such as low costs, shorter analysis times, and general availability (e.g., online databases), and are often used to design in vitro and, subsequently, in vivo tests. This review focuses on the possible use of in silico computerized methods to assess the potential of food as a source of these health-relevant biomolecules by using examples from the literature on meat and meat products. This review also provides information and important suggestions for analyzing peptides in terms of assessing their best sources, and screening those resistant to digestive factors and that show biological activity. The information provided in this review could contribute to the development of new sources of foods as biomolecules important for preventing or treating food-related chronic diseases, such as obesity, hypertension, and diabetes.

Oligopeptides from Jinhua ham prevent alcohol-induced liver damage by regulating intestinal homeostasis and oxidative stress in mice

The current study aimed to evaluate the protective activity of peptides isolated from Jinhua ham (JHP) against alcoholic liver disease (ALD) and the mechanisms by which JHP prevents against ALD. The tangential flow filtration (TFF) combined with size exclusion chromatography (SEC) and reversed-phase high performance liquid chromatography (RP-HPLC) were used to isolate the JHP. Then the hepatoprotective activity of peptides was evaluated through experiments in mice. The primary structure of the peptide with the strongest liver protective activity was Lys-Arg-Gln-Lys-Tyr-Asp (KRQKYD) and the peptide was derived from the myosin of Jinhua ham, which were both identified by LC-MS/MS. Furthermore, the mechanism of KRQKYD prevention against ALD was attributed to the fact that KRQKYD increases the abundance of Akkermansia muciniphila in the gut and decreases the abundance of Proteobacteria (especially Escherichia_Shigella). The LPS-mediated liver inflammatory cascade was reduced by protecting the intestinal barrier, increasing the tight connection of intestinal epithelial cells and reducing the level of LPS in the portal venous circulation. KRQKYD could inhibit the production of ROS by upregulating the expression of the NRF2/HO-1 antioxidant defense system and by reducing oxidative stress injury in liver cells. This study can provide a theoretical foundation for the application of JHP in the protection of liver from ALD.

Potential DPP IV Inhibitory Peptides from Dry-Cured Pork Loins after Hydrolysis: An In Vitro and In Silico Study

Peptidyl peptidase IV (DPP-IV) is a pharmacotherapeutic target in type 2 diabetes, and inhibitors of this enzyme are an important class of drugs for the treatment of type 2 diabetes. In the present study, peptides (<7 kDa) isolated from dry-cured pork loins after pepsin and pancreatin hydrolysis were identified by mass spectrometry and tested as potential inhibitors of DPP-IV by the in silico method. Two peptides, namely WTIAVPGPPHS from myomesin (water-soluble fraction, A = 0.9091) and FKRPPL from troponin (salt-soluble fraction, A = 0.8333), were selected as the most promising inhibitors of DPP-IV. Both peptides were subjected to ADMET analysis. Fragments of these peptides showed promising drug-likeness properties as well as favorable absorption, distribution, metabolism, excretion, and toxicity functions, suggesting that they are novel leads in the development of DPP-IV inhibitors from food.

In silico analysis of novel dipeptidyl peptidase-IV inhibitory peptides released from Macadamia integrifolia antimicrobial protein 2 (MiAMP2) and the possible pathways involved in diabetes protection

The aim of the present study was to screen novel dipeptidyl peptidase IV (DPP-IV) inhibitory peptides from Macadamia integrifolia antimicrobial protein 2 (MiAMP2) and evaluate the potential antidiabetic targets and involved signaling pathways using in silico approaches. In silico digestion of MiAMP2 with pepsin, trypsin and chymotrypsin was performed with ExPASy PeptideCutter and the generated peptides were subjected to BIOPEP-UWM, iDrug, INNOVAGEN and Autodock Vina for further analyses. Six novel peptides EQVR, EQVK, AESE, EEDNK, EECK, and EVEE were predicted to possess good DPP-IV inhibitory potentials, water solubility, and absorption, distribution, metabolism, excretion, and toxicity properties. Molecular dynamic simulation and molecular docking displayed that AESE was the most potent DPP-IV inhibitory peptide and can bind with the active sites of DPP-IV through hydrogen bonding and van der Waals forces. The potential antidiabetic targets of AESE were retrieved from SwissTargetPrediction and GeneCards databases. Protein-protein interaction analysis identified BIRC2, CASP3, MMP7 and BIRC3 to be the hub targets. Moreover, the KEGG pathway enrichment analysis showed that AESE prevented diabetes through the apoptosis and TNF signaling pathways. These results will provide new insights into utilization of MiAMP2 as functional food ingredients for the prevention and treatment of diabetes.

Bioactive Peptides as Potential Nutraceuticals for Diabetes Therapy: A Comprehensive Review

Diabetes mellitus is a major public health concern associated with high mortality and reduced life expectancy. The alarming rise in the prevalence of diabetes is linked to several factors including sedentary lifestyle and unhealthy diet. Nutritional intervention and increased physical activity could significantly contribute to bringing this under control. Food-derived bioactive peptides and protein hydrolysates have been associated with a number health benefits. Several peptides with antidiabetic potential have been identified that could decrease blood glucose level, improve insulin uptake and inhibit key enzymes involved in the development and progression of diabetes. Dietary proteins, from a wide range of food, are rich sources of antidiabetic peptides. Thus, there are a number of benefits in studying peptides obtained from food sources to develop nutraceuticals. A deeper understanding of the underlying molecular mechanisms of these peptides will assist in the development of new peptide-based therapeutics. Despite this, a comprehensive analysis of the antidiabetic properties of bioactive peptides derived from various food sources is still lacking. Here, we review the recent literature on food-derived bioactive peptides possessing antidiabetic activity. The focus is on the effectiveness of these peptides as evidenced by in vitro and in vivo studies. Finally, we discuss future prospects of peptide-based drugs for the treatment of diabetes.

Bioactive Peptides in Preventative Healthcare: An Overview of Bioactivities and Suggested Methods to Assess Potential Applications

Food derived bioactive peptides can be generated from various protein sources and usually consist of between 2-30 amino acids with bulky, side-chain aromatic amino acids preferred in the ultimate and penultimate positions at the C-terminal end of the amino acid chain. They are reported to impart a myriad of preventative health beneficial effects to the consumer once ingested and these include heart health benefits through inhibition of enzymes including renin (EC 3.4.23.15) and angiotensin- I-converting enzyme (ACE-1; EC 3.4.15.1) within the renin angiotensin aldosterone system (RAAS) anti-inflammatory (due to inhibition of ACE-I and other enzymes) and anti-cancer benefits, prevention of type-2 diabetes through inhibition of dipeptidyl peptidase IV (DPP-IV), bone and dental strength, antimicrobial and immunomodulatory effects and several others. Peptides have also reported health benefits in the treatment of asthma, neuropathic pain, HIV and wound healing. However, the structure, amino acid composition and length of these peptides, along with the quantity of peptide that can pass through the gastrointestinal tract and often the blood-brain barrier (BBB), intact and reach the target organ, are important for the realisation of these health effects in an in vivo setting. This paper aims to collate recent important research concerning the generation and detection of peptides in the laboratory. It discusses products currently available as preventative healthcare peptide options and relevant legislation barriers to place a food peptide product on the market. The review also highlights useful in silico computer- based methods and analysis that may be used to generate specific peptide sequences from proteins whose amino acid sequences are known and also to determine if the peptides generated are unique and bioactive. The topic of food-derived bioactive peptides for health is of great interest to scientific research and industry due to evolving drivers in food product innovation, including health and wellness for the elderly, infant nutrition and optimum nutrition for sports athletes and the humanisation of pets. This paper provides an overview of what is required to generate bioactive peptide containing hydrolysates, what methods should be used in order to characterise the beneficial health effects of these hydrolysates and the active peptide sequences, potential applications of bioactive peptides and legislative requirements in Europe and the United States. It also highlights success stories and barriers to the development of peptide-containing food products that currently exist.

Isolation and identification of bioactive peptides from Xuanwei ham that rescue oxidative stress damage induced by alcohol in HHL-5 hepatocytes

Peptides extracted from Xuanwei ham (XHP) can prevent free radical-induced diseases. The aim of the present study was to isolate and identify bioactive peptides from Xuanwei hams that rescue the oxidative stress damage induced by alcohol in HHL-5 hepatocytes. Alcohol-treated HHL-5 human hepatocytes were utilized as the alcohol-induced hepatocyte damage model to evaluate the effects of XHP on amounts of aminotransferase (ALT), aspartate aminotransferase (AST) and malondialdehyde (MDA). The result showed that XHP could significantly reduce ALT, AST and MDA, the major biomarkers of liver damage. The crude XHP was separated by size exclusion chromatography, followed by the evaluation of respective activities. Then, the most active components were further separated by RP-HPLC, and their activities were evaluated according to the above method. The peptide was identified as a hexapeptide with the sequence of Asn-Pro-Pro-Lys-Phe-Asp (NPPKFD) through LC-MS/MS. Further, the molecular mechanisms by which NPPKFD prevents alcohol-induced oxidative stress damage were revealed. Results showed that the hexapeptide could downregulate CYP2E1 expression, reduce generation of ROS and enhance oxidant defense systems via the activation of NrF2/HO-1 pathway. The findings suggest that Xuanwei ham can be used as a new source of bioactive peptides for protection from alcohol-induced liver damage.

Recent Progress in Enzymatic Release of Peptides in Foods of Animal Origin and Assessment of Bioactivity

There is a wide variety of peptides released from food proteins that are able to exert a relevant benefit for human health, such as angiotensin-converting enzyme inhibition, antioxidant, anti-inflammatory, hypoglucemic, or antithrombotic activity, among others. This manuscript is reviewing the recent advances on enzymatic mechanisms for the hydrolysis of proteins from foods of animal origin, including the types of enzymes and mechanisms of action involved, the strategies followed for the isolation and identification of bioactive peptides through advanced proteomic tools, and the assessment of bioactivity and its beneficial effects. Specific applications in fermented and/or ripened foods where a significant number of bioactive peptides have been reported with relevant in vivo physiological effects on laboratory rats and humans as well as the hydrolysis of animal food proteins for the production of bioactive peptides are also reviewed.

Comprehensive identification of native medium-sized and short bioactive peptides in sea bass muscle

Native peptides from sea bass muscle were analyzed by two different approaches: medium-sized peptides by peptidomics analysis, whereas short peptides by suspect screening analysis employing an inclusion list of exact m/z values of all possible amino acid combinations (from 2 up to 4). The method was also extended to common post-translational modifications potentially interesting in food analysis, as well as non-proteolytic aminoacyl derivatives, which are well-known taste-active building blocks in pseudo-peptides. The medium-sized peptides were identified by de novo and combination of de novo and spectra matching to a protein sequence database, with up to 4077 peptides (2725 modified) identified by database search and 2665 peptides (223 modified) identified by de novo only; 102 short peptide sequences were identified (with 12 modified ones), and most of them had multiple reported bioactivities. The method can be extended to any peptide mixture, either endogenous or by protein hydrolysis, from other food matrices.

COVID-19 and Senotherapeutics: Any Role for the Naturally-occurring Dipeptide Carnosine?

It is suggested that the non-toxic dipeptide carnosine (beta-alanyl-L-histidine) should be examined as a potential protective agent against COVID-19 infection and inflammatory consequences especially in the elderly. Carnosine is an effective anti-inflammatory agent which can also inhibit CD26 and ACE2 activity. It is also suggested that nasal administration would direct the peptide directly to the lungs and escape the attention of serum carnosinase.

Meat Proteins as Dipeptidyl Peptidase IV Inhibitors and Glucose Uptake Stimulating Peptides for the Management of a Type 2 Diabetes Mellitus In Silico Study

Diabetes mellitus is a non-communicable disease entity currently constituting one of the most significant health problems. The development of effective therapeutic strategies for the prevention and/or treatment of diabetes mellitus based on the selection of methods to restore and maintain blood glucose homeostasis is still in progress. Among the different courses of action, inhibition of dipeptidyl peptidase IV (DPP-IV) can improve blood glucose control in diabetic patients. Pharmacological therapy offering synthetic drugs is commonly used. In addition to medication, dietary intervention may be effective in combating metabolic disturbances caused by diabetes mellitus. Food proteins as a source of biologically active sequences are a potential source of anti-diabetic peptides (DPP-IV inhibitors and glucose uptake stimulating peptides). This study showed that in silico pork meat proteins digested with gastrointestinal enzymes are a potential source of bioactive peptides with a high potential to control blood glucose levels in patients with type 2 diabetes mellitus. Analysis revealed that the sequences released during in silico digestion were small dipeptides (with an average weight of 270.07 g mol^-1), and most were poorly soluble in water. The selected electron properties of the peptides with the highest bioactivity index (i.e., GF, MW, MF, PF, PW) were described using the DFT method. The contribution of hydrophobic amino acids, in particular Phe and Trp, in forming the anti-diabetic properties of peptides released from pork meat was emphasized.

Changes in the perception of bitter constituents in thermally treated yeast extract

BACKGROUND

Many studies have been performed over the past four decades to identify and quantify the odor-active key volatiles in yeast extract (YE) but knowledge of the nonvolatile taste compounds is still rather fragmentary. In particular, research on bitter peptides with various structures during the thermal treatment of YE is still scarce.

RESULTS

Compounds imparting a bitter taste to thermally treated YE were investigated using sensory-guided fractionation. This research found that when the treatment temperature reached 130 °C, bitter peptides were generated. Sensory evaluation of the purified, synthesized peptides revealed that four of these peptides showed a pronounced bitter taste with a taste dilution (TD) factor from 5 to 9. Guidance is provided for the production of bitter peptides in the flavor industry.

CONCLUSION

Based on results from previous work on umami peptides, and this study, keeping the thermal reaction temperature under 120 °C could maximize the umami flavor and control bitterness so that it remains in an acceptable range. © 2019 Society of Chemical Industry.

Peptides with Potential Cardioprotective Effects Derived from Dry-Cured Ham Byproducts

The interest in using food byproducts as a source of bioactive peptides has increased significantly in the recent years. The goal of this work was to determine the presence and stability of peptides showing angiotensin I-converting enzyme (ACE-I), endothelin-converting enzyme (ECE), dipeptidyl peptidase-IV (DPP-IV), and platelet-activating factor-acetylhydrolase (PAF-AH) inhibitory activity derived from dry-cured ham bones, which could exert cardiovascular health benefits. ACE-I and DPP-IV inhibitory peptides were stable against heating typically used in Mediterranean household cooking methods and also to in vitro digestion. PAF-AH inhibitory activity significantly increased following simulated gastrointestinal digestion whereas ECE inhibitory significantly decreased ( P < 0.05). The mass spectrometry analysis revealed a notable degradation of hemoglobin-derived peptides after simulated digestion, and the release of a large number of dipeptides that may have contributed to the observed bioactivities. These results suggest that natural peptides from Spanish dry-cured ham bones could contribute to a positive impact on cardiovascular health.

Discovery of Food-Derived Dipeptidyl Peptidase IV Inhibitory Peptides: A Review

Diabetes is a chronic metabolic disorder which leads to high blood sugar levels over a prolonged period. Type 2 diabetes mellitus (T2DM) is the most common form of diabetes and results from the body’s ineffective use of insulin. Over ten dipeptidyl peptidase IV (DPP-IV) inhibitory drugs have been developed and marketed around the world in the past decade. However, owing to the reported adverse effects of the synthetic DPP-IV inhibitors, attempts have been made to find DPP-IV inhibitors from natural sources. Food-derived components, such as protein hydrolysates (peptides), have been suggested as potential DPP-IV inhibitors which can help manage blood glucose levels. This review focuses on the methods of discovery of food-derived DPP-IV inhibitory peptides, including fractionation and purification approaches, in silico analysis methods, in vivo studies, and the bioavailability of these food-derived peptides. Moreover, food-derived DPP-IV inhibitory peptides discovered during this decade are listed and distributed in a 3D scatter plot graph based on their IC₅₀, molecular weight, and grand average of hydropathicity values, which can help us to understand the relationship between the features of the peptides and their activities.

In vitro digestion of rice bran proteins produces peptides with potent inhibitory effects on α-glucosidase and angiotensin I converting enzyme

BACKGROUND

The bioactivities of peptides released from the digestion of rice bran protein under in vitro simulated human digestive conditions were investigated. Four protein fractions extracted from rice bran were digested and the hydrolysates were fractionated by ultrafiltration and anion exchange chromatography. α-Glucosidase and angiotensin converting enzyme (ACE) inhibitory activities of the crude hydrolysates and their fractions were determined.

RESULTS

Peptides with molecular weight (MW) < 3 kDa gave markedly higher α-glucosidase inhibitory activities than the crude digests, while the ACE inhibitory activities of the MW < 3 kDa fractions were similar to those of the crude extracts. Peptides from albumin and glutelin exhibited the greatest inhibitory effects on α-glucosidase and ACE at 52.43 ± 2 mg acarbose equivalent and 170.13 ± 2.2 nmol captopril equivalent g^-1 peptide respectively. Liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis identified 39 peptides in the most active fraction of the hydrolysates, and 37 of these contained peptide sequences that are known to exhibit antidiabetic or antihypertensive activities.

CONCLUSION

Consumption of rice bran proteins can potentially lead to generation of bioactive peptides in the digestive tract with substantial health benefits. ACE and α-glucosidase inhibitory activities of the digests of rice bran proteins, and albumin and glutelin in particular, were especially strong, comparable to that of the standard drugs. © 2017 Society of Chemical Industry.

Predicted Release and Analysis of Novel ACE-I, Renin, and DPP-IV Inhibitory Peptides from Common Oat (Avena sativa) Protein Hydrolysates Using in Silico Analysis

The renin-angiotensin-aldosterone system (RAAS) plays an important role in regulating hypertension by controlling vasoconstriction and intravascular fluid volume. RAAS itself is largely regulated by the actions of renin (EC 3.4.23.15) and the angiotensin-I-converting enzyme (ACE-I; EC 3.4.15.1). The enzyme dipeptidyl peptidase-IV (DPP-IV; EC 3.4.14.5) also plays a role in the development of type-2 diabetes. The inhibition of the renin, ACE-I, and DPP-IV enzymes has therefore become a key therapeutic target for the treatment of hypertension and diabetes. The aim of this study was to assess the bioactivity of different oat (Avena sativa) protein isolates and their ability to inhibit the renin, ACE-I, and DPP-IV enzymes. In silico analysis was carried out to predictthe likelihood of bioactive inhibitory peptides occurring from oat protein hydrolysates following in silico hydrolysis with the proteases papain and ficin. Nine peptides, including FFG, IFFFL, PFL, WWK, WCY, FPIL, CPA, FLLA, and FEPL were subsequently chemically synthesised, and their bioactivities were confirmed using in vitro bioassays. The isolated oat proteins derived from seven different oat varieties were found to inhibit the ACE-I enzyme by between 86.5 ± 10.7% and 96.5 ± 25.8%, renin by between 40.5 ± 21.5% and 70.9 ± 7.6%, and DPP-IV by between 3.7 ± 3.9% and 46.2 ± 28.8%. The activity of the synthesised peptides was also determined.

Features of dipeptidyl peptidase IV (DPP-IV) inhibitory peptides from dietary proteins

Dipeptidyl peptidase IV (DPP-IV) is involved in incretin hormone processing and therefore plays a key role in glycemic regulation. This review summarizes the latest developments in food protein-derived DPP-IV inhibitory peptides. The in silico approaches currently used to develop targeted strategies for the enzymatic release of DPP-IV inhibitory peptides from food proteins are outlined. The features within the primary sequences of potent DPP-IV inhibitory di-, tri-, and larger peptides, having half maximal inhibitory activity (IC₅₀ ) < 100 µM, were evaluated and the outcomes are presented herein. It is proposed that detailed analysis of those food derived peptides identified in humans following ingestion may constitute a practical strategy for the targeted identification of novel bioavailable DPP-IV inhibitory peptides. Human intervention studies are required as the specific role of food protein-derived DPP-IV inhibitory peptides in the regulation of glycaemia in humans remains to be fully elucidated. PRACTICAL APPLICATIONS: This review provides recent information on dipeptidyl peptidase IV (DPP-IV) inhibitory peptides arising from food protein hydrolysates. Small animal studies have demonstrated that food protein hydrolysates with in vitro DPP-IV inhibitory properties also display antidiabetic activity. DPP-IV inhibitory peptides may be used as food ingredients to improve glycemic regulation in Type 2 diabetics. Therefore, the development of potent DPP-IV inhibitory hydrolysates containing bioavailable peptides in humans is of significant interest. This may help in the formulation of foods containing physiologically relevant doses of bioactive hydrolysates/peptides. Acquisition of detailed knowledge of DPP-IV inhibitory peptide features via the utilization of in silico tools may help to optimize the release of potent DPP-IV inhibitory peptides during enzymatic hydrolysis of food proteins. This review provides information on features within the primary sequences of potent DPP-IV inhibitory peptides and current in silico strategies which may be used to inform on the targeted enzymatic hydrolysis of food proteins.

The Effect of Regular Intake of Dry-Cured Ham Rich in Bioactive Peptides on Inflammation, Platelet and Monocyte Activation Markers in Humans

Background and aims: Dietary studies have shown that active biopeptides provide protective health benefits, although the mediating pathways are somewhat uncertain. To throw light on this situation, we studied the effects of consuming Spanish dry-cured ham on platelet function, monocyte activation markers and the inflammatory status of healthy humans with pre-hypertension. Methods: Thirty-eight healthy volunteers with systolic blood pressure of >125 mmHg were enrolled in a two-arm crossover randomized controlled trial. Participants received 80 g/day dry-cured pork ham of >11 months proteolysis or 100 g/day cooked ham (control product) for 4 weeks followed by a 2-week washout before “crossing over” to the other treatment for 4 more weeks. Soluble markers and cytokines were analyzed by ELISA. Platelet function was assessed by measuring P-selectin expression and PAC-1 binding after ADP (adenosine diphosphate) stimulation using whole blood flow cytometry. Monocyte markers of the pathological status (adhesion, inflammatory and scavenging receptors) were also measured by flow cytometry in the three monocyte subsets after the interventional period. Results: The mean differences between dry-cured ham and cooked ham followed by a time period adjustment for plasmatic P-selectin and interleukin 6 proteins slightly failed (p = 0.062 and p = 0.049, respectively), notably increased for MCP-1 levels (p = 0.023) while VCAM-1 was not affected. Platelet function also decreased after ADP stimulation. The expression of adhesion and scavenging markers (ICAM1R, CXCR4 and TLR4) in the three subsets of monocytes was significantly higher (all p < 0.05). Conclusions: The regular consumption of biopeptides contained in the dry-cured ham but absent in cooked ham impaired platelet and monocyte activation and the levels of plasmatic P-selectin, MCP-1 and interleukin 6 in healthy subjects. This study strongly suggests the existence of a mechanism that links dietary biopeptides and beneficial health effects.

The development of bioactive peptides from dietary proteins as a dipeptidyl peptidase IV inhibitor for the management of type 2 diabetes

One of the new approaches to the management of type 2 diabetes mellitus (T2DM) consists of orally administered dipeptidyl peptidase-IV (DPP-IV) inhibitors. These synthetic drug inhibitors are reported to have some side effects and that subsequently limits their applications. There is a growing interest to develop natural DPP-IV inhibitors that will be potent without undesirable side effects. Many in vitro and some in vivo studies have highlighted the potential of food-derived peptides functioning as effective DPPIV inhibitors. Bioactive peptides within original food-derived proteins are inactive but can be activated by being released during food processing (by enzymatic hydrolysis or fermentation) or during gastrointestinal digestion. Hence, the utilization of computer-aided techniques as screening tools may be helpful in predicting the potential of food proteins as precursors of DPP-IV inhibitory peptides. This paper reviews the current literature on DPP-IV inhibitory peptides, focusing on their in vitro activity and in vivo antidiabetic effects. In addition, the feasibility of various in silico approaches is also summarized in this review.