Search Results (98)

Natural food-derived proteins are increasingly explored as alternatives to synthetic inhibitors for managing Type 2 diabetes mellitus. Despite the recognized health-promoting properties of Morchella esculenta, the potential of its bioactive proteins to modulate glucose metabolism remains largely unexplored. This study systematically investigated the structural basis and hypoglycemic mechanisms of MEP5 (Morchella esculenta Protein 5), a fucose-specific lectin from M. esculenta, using an integrated in silico pipeline. MEP5 (33.12 kDa) adopts a stable β-sheet-rich conformation and harbors a conserved fucose-binding carbohydrate-recognition domain. Protein–protein docking revealed that intact MEP5 binds directly to surface glycans of human α-glucosidase, generating steric hindrance that obstructs the catalytic pocket. Simulated gastrointestinal digestion yielded a highly bioavailable peptide profile. Following a rigorous multiparametric screening for toxicity, allergenicity, and water solubility, 11 short oligopeptides were identified as potent dipeptidyl peptidase-IV (DPP-IV) inhibitors. Molecular docking demonstrated that the top-ranked peptides, QPPR, DGTY, and DPDSH, occupy the S2 pocket of DPP-IV and form hydrogen bonds with catalytic triad residues (Ser630/His740). These findings delineate a dual-stage hypoglycemic mechanism, pre-digestion enzymatic blockade and post-digestion incretin regulation, and support the potential of MEP5 as a multifunctional candidate for glucose homeostasis-oriented functional foods. Full article

The growing demand for functional foods reflects greater consumer awareness of diet–health links, with bioactive peptides receiving increasing attention for their health-promoting effects. In this study, bioactive peptides exhibiting antioxidant, dipeptidyl peptidase-IV (DPP-IV) inhibitory, and angiotensin-converting enzyme (ACE) inhibitory activities were produced from a jack bean (Canavalia ensiformis) protein isolate using a continuous proteolysis system with two enzymes. This study encompassed two major phases: isolating protein from jack beans and implementing a continuous enzymatic hydrolysis process. Key variables examined included the enzyme-to-substrate ratio ([E]/[S]), pH level, and residence time (τ). Optimal performance was achieved at [E]/[S] = 5%, pH = 7.5, and τ = 12 h, yielding a permeate with peptide content of 0.6143 mg SE/mL, along with notable antioxidant capacity and ACE inhibition of 0.0454 mg TEAC/mL and 92.18%, respectively. These results confirm that the jack bean protein isolate is a viable substrate for generating multifunctional bioactive peptides. This study provides a foundation for scalable and sustainable production of functional food ingredients from underutilized legumes using continuous bioprocessing technology. Industrial relevance: Integrating a stirred tank reactor with membrane separation provides a promising approach for continuous bioactive peptide production using a free-enzyme system, helping to streamline processing, reduces the demand for enzyme immobilization, and minimizes batch-to-batch variability. This study shows that continuous hydrolysis of jack bean protein isolate in EMR can enhance antioxidant activity and ACE inhibition of the hydrolysates. This approach offers a safer and more efficient route to support the commercialization of jack bean-based functional products. Full article

To enhance the screening efficiency of bioactive peptides, an AI-driven approach was employed to screen DPP-IV inhibitory peptides from goat blood proteins by an integrated in silico, in vitro, and machine learning strategy. Furthermore, the inhibitory mechanism of DPP-IV inhibitory peptides was elucidated by kinetics, molecular docking and simulation. Additionally, their in vitro digestive stability was assessed. In silico results revealed that goat blood proteins were promising precursors of DPP-IV inhibitory peptides, while bromelain was the optimal protease. Their peptide sequences were further identified by peptidomics and predicted by self-developed machine learning models (LightGBM) to identify the potent DPP-IV inhibitory peptides. Two novel DPP-IV inhibitory peptides were identified (FPL and FPHFDL). Enzyme kinetics, molecular docking and molecular simulation data indicated that FPL served as a competitive inhibitor, whereas FPHFDL was a non-competitive inhibitor. Overall, the integrative in silico and in vitro strategy is feasible for rapid screening of DPP-IV inhibitory peptides from goat blood proteins. Full article

Dipeptidyl-peptidase IV (DPP4) inhibitors have shown potential anti-tumor properties. This study investigates the therapeutic potential of evogliptin, a DPP4 inhibitor, both as a single agent and in combination with temozolomide (TMZ), in glioma models. In vitro studies were performed using U87 and U373 glioma cell lines exposed to different concentrations of TMZ (250, 500 μM) and evogliptin (250, 500 ng/mL), either alone or together, for 24, 48, and 72 h. Cell viability was determined with the MTT assay. In vivo effectiveness was tested in a xenograft mouse model treated with intraperitoneal injections of evogliptin (60 mg/k g/day), TMZ (15 mg/kg/day), or their combination over 3 weeks. The combination of TMZ and evogliptin markedly reduced cell viability compared to single-agent treatments. DPP4 mRNA levels decreased more substantially with combination therapy. miRNA expression profiling with Affymetrix arrays indicated that certain miRNAs, such as miR-4440 and miR-6780b-5p, were upregulated after treatment with evogliptin or the combination regimen, whereas others were downregulated. These miRNAs could play a role in limiting glioma growth through DPP4 regulation. In the animal model, evogliptin alone did not provide a survival advantage. Analysis of TCGA data showed that glioma patients with decreased DPP4 expression had improved survival rates. The co-administration of evogliptin and temozolomide resulted in distinct miRNA profile changes. Nevertheless, both in vitro and in vivo, the added cytotoxicity from the combination was minimal. Full article

The tree bean (Parkia timoriana), an underutilized legume valued for its nutritional profile, represents a potential source of bioactive peptides for diabetes management. To our knowledge, this is the first study to identify and characterize DPP-IV inhibitory peptides derived from tree bean seed protein hydrolysates. The tree bean proteins were digested with trypsin, thermolysin, chymotrypsin, pepsin, and simulated gastrointestinal (SGI) enzymes, among which SGI hydrolysis yielded the highest degree of hydrolysis (14%) and strongest DPP-IV inhibitory activity (IC₅₀ = 1289 ± 58 µg/mL). Guided by DPP-IV inhibitory assays, sequential fractionation using strong cation exchange and RP-HPLC yielded the most potent fraction, H5, with an IC₅₀ of 949 ± 50 µg/mL. After peptide identification and synthesis, APLGPF (AF6) emerged as the most potent inhibitor, with an IC₅₀ of 396 ± 18 µM. Enzyme kinetics revealed a non-competitive inhibition mechanism, corroborated by molecular docking, which indicated binding at an allosteric site of DPP-IV. Furthermore, AF6 remained stable under simulated gastrointestinal digestion and enzymatic exposure, highlighting its resistance to proteolysis. Taken together, these findings highlight P. timoriana as an underexplored source of peptides with DPP-IV inhibitory activity and identify AF6 as a promising lead for developing functional foods or nutraceuticals aimed at type 2 diabetes management. Full article

As an emerging natural source of DPP-IV inhibition strategy, we report for the first time the use of Lithobates catesbeianus skin gelatin (LSG) as a novel source for DPP-IV inhibitory peptides in this study. Through enzymatic hydrolysis with multiple proteases, the papain-treated hydrolysate exhibited superior performance in hydrolysis degree, protein recovery, and DPP-IV inhibition, with 93.47% of peptides under 1 kDa. Subsequent separation and peptidomics analysis identified 13 previously unreported peptides. Molecular docking and in silico screening pinpointed four candidate peptides, i.e., LGPQR, RGFDQ, RGPVGP, and RLDDVT, which were then synthesized and functionally validated. Enzyme kinetic studies revealed that these peptides acted via competitive or mixed-type inhibition mechanisms. Notably, this study uncovered the bio-functional potential of amphibian-derived gelatin and provided a new strategy for natural DPP-IV inhibitor discovery through integrated enzymatic, computational, and biochemical approaches. This work pioneered the use of amphibian skin gelatin in antidiabetic peptide discovery and laid the foundation for its application in functional foods. Full article

Dry-cured ham is a traditional food in the Mediterranean diet, which, in addition to its sensory qualities, is a natural source of bioactive peptides generated during the curing process through the action of endogenous enzymes on muscle and sarcoplasmic proteins. These low-molecular-weight peptides have attracted growing interest due to their multiple bioactivities, including antihypertensive, antioxidant, antimicrobial, antidiabetic, and anti-inflammatory effects described in vitro, in vivo, and in preliminary human studies. The identification of specific sequences, such as AAPLAP, KPVAAP, and KAAAAP (ACE inhibitors), SNAAC and GKFNV (antioxidants), RHGYM (antimicrobial), and AEEEYPDL and LGVGG (dipeptidyl peptidase-IV and α-glucosidase inhibitors), has been possible thanks to the use of peptidomics techniques, tandem mass spectrometry, and bioinformatics tools that allow their activity to be characterized, their digestive stability to be predicted, and their bioavailability to be evaluated. This review article summarizes current knowledge on the bioactivities of peptides derived from dry-cured ham, advances in their functional characterization, and challenges associated with their application in functional foods and nutraceuticals, with the aim of providing a comprehensive overview of their potential in health promotion and chronic disease prevention. Full article

Background/Objectives: Essential amino acid (EAA) supplementation is often employed in sportive and clinical nutrition due to EAAs’ role in muscle mass maintenance and growth. EAAs are also involved in insulin and glucagone regulation in diabetes management, but only few reports investigate their possible implication as dipeptidyl peptidase-IV (DPP-IV) inhibitors and their effect on the stability and secretion of enteroendocrine hormones. A blend of EAAs (called GAF) available as a food supplement, in a specific qualitative and quantitative ratio, was investigated to address its in vitro bioaccessibility, its hypoglycemic properties in vitro and in situ on cellular models, and its safety on intestinal Caco-2 cells. Methods: GAF was subjected to the INFOGEST static digestion protocol, producing the iGAF sample. iGAf DPP-IV inhibitory properties were investigated both in vitro and in situ on Caco-2 cells. Then, STC-1 enteroendocrine cells were employed alone and in co-culture with Caco-2 cells to evaluate iGAF’s impact on glucagon-like peptide 1 (GLP-1) hormone secretion. Results: The study demonstrates that the present EAAs blend is stable and bioaccessible after simulated gastrointestinal digestion, and it is safe at the intestinal cellular level. It inhibits DPP-IV enzyme both in vitro and in situ and promotes GLP-1 secretion by enteroendocrine cells. Conclusions: The sample demonstrated safety at the intestinal level and showed hypoglycemic properties by acting on a dual synergic mechanism that involves DPP-IV enzyme inhibition and GLP-1 hormone stimulation. Full article

Type 2 diabetes mellitus (T2DM) is a complex and prevalent metabolic disorder, and dipeptidyl peptidase 4 (DPP4) inhibitors have proven effective, yet the identification of novel inhibitors remains challenging due to the vastness of chemical space. In this study, we developed DPPPRED-IV, a web-based ensembled system integrating both binary classification and continuous regression Quantitative Structure Activity Relationships (QSAR) models to predict human DPP4 inhibitory activity. A curated dataset of 4 676 ChEMBL compounds was subjected to genetic algorithm descriptor selection and multiple machine learning algorithms; classification models were combined via a soft voting ensemble, while regression models estimated IC₅₀ values. All models underwent external 10-fold cross-validation and applicability domain analysis. The final models were integrated into a user-friendly web server, allowing predictions from SMILES inputs. Experimental testing of 29 MolPort compounds at 1.5 µM confirmed that 14 predicted actives exhibited significant inhibition, supporting the tool’s performance in early-stage screening. DPPPRED IV is freely available within the ChemoPredictionSuite and offers a resource to accelerate decision making, reduce costs and minimize animal use in T2DM drug discovery. Full article

Hypertension and type 2 diabetes are the major metabolic syndromes, often managed using synthetic ACE and DPP-IV inhibitors that may cause adverse effects on health. This study investigated Bambara groundnut protein hydrolysates as a natural source of dual ACE- and DPP-IV-inhibitory peptides. Protein isolates were hydrolyzed using Flavourzyme, and the resulting peptides were fractionated using membranes with different molecular weight cut-offs. Those fractions were then analyzed for enzyme inhibition. Peptides were identified by LC-MS/MS and screened using PeptideRanker and BIOPEP-UWM, followed by molecular docking against ACE (PDB: 1O8A) and DPP-IV (PDB: 1NU6). The >10 kDa and 5–10 kDa fractions showed the highest ACE- and DPP-IV-inhibitory activities, respectively. Some peptides such as YKDGLYSPHW, LPVSTPGKF, and EPWWPK displayed strong binding affinities (ΔG: −10.2 to −11.3 kcal/mol for ACE, −8.6 to −9.1 kcal/mol for DPP-IV) and interacted with key catalytic residues, including His387 and Glu411 in ACE, and Ser630, Glu205, and Phe357 in DPP-IV. These findings highlight the potential of Bambara groundnut hydrolysates or peptides as a source of natural ACE and DPP-IV inhibitors. Full article

Bovine milk protein preparations (MPPs), namely micellar casein concentrate (MCC), serum protein concentrate (SPC), and MCC with ultrafiltrated buttermilk permeate (MBP), were analyzed as sources of inhibitors of angiotensin-converting enzyme (i.e., ACE) and dipeptidylpeptidase IV (i.e., DPP-IV) as well as antioxidative peptides. The studies involved in silico predictions of the release of biopeptides from bovine milk proteins. Then, all MPPs were subjected to the simulated gastrointestinal digestion using the INFOGEST protocol. Results using a BIOPEP-UWM database tool indicated that 59 biopeptides exhibiting the above-mentioned activities could be produced upon the action of pepsin, trypsin, and chymotrypsin. Thirty-six biopeptides were identified in at least one of the three MPPs subjected to the INFOGEST protocol. MCC before simulated digestion exhibited the strongest ACE-inhibiting activity among all MPPs (IC₅₀ = 1.856 mg/mL). The weakest ACE inhibitory effect was demonstrated for MBP after duodenal digestion (i.e., MBP D; IC₅₀ = 7.627 mg/mL). The above MPP showed the strongest DPP-IV-inhibiting activity (IC₅₀ = 0.0067 mg/mL). All MPPs exhibited antioxidative activity, with the strongest ABTS^•+ (i.e., 2,2′-azino-bis(3-ethylbenzotialozline-6-sulfonic acid) radical scavenging effect shown for MBP D (IC₅₀ = 2.754 mg/mL), and the strongest DPPH^• (i.e., 2,2-diphenyl-β-picrylhydrazyl) radical scavenging activity (IC₅₀ = 1.238 mg/mL) demonstrated for SPC D. Among all MPPs, SPC D also exhibited the highest FRAP (i.e., Ferric Reducing Antioxidant Power) bioactivity (IC₅₀ = 13.720 mg/mL), whereas MBP D was the MPP with the lowest FRAP potential (IC₅₀ = 20.140 mg/mL). The present study results show the potential of all MPPs as functional additives to support health-beneficial functions of dairy products. Full article

Background: Type 2 diabetes mellitus (T2DM) is a prevalent metabolic disease with global implications, necessitating effective management strategies. Dipeptidyl peptidase IV (DPP-4) inhibitors have shown promise as potent agents for T2DM treatment. Methods: This study combines chemical synthesis, molecular modelling, and inhibitory activity assays to characterise the structure–activity relationship of novel isomeric 1,2,4-oxadiazole-substituted derivatives of the 2-azabicyclo[2.2.1]heptane scaffold acylated with (R)-3-amino-4-(2,4,5-trifluorophenyl)butanoic acid. Results: In this article, we demonstrate the efficacy of new compounds as robust inhibitors of DPP-4. The attempts to further modify neogliptin (our lead compound described previously) resulted in a more potent DPP-4 inhibitor 9a (IC₅₀ = 4.3 nM), which did not mediate any substantial inhibition of DPP-8 and DPP-9. Conclusions: This study demonstrates that pseudo peptides incorporating (R)-3-amino-4-(2,4,5-trifluorophenyl)butanoic acid, a 2-aza-bicyclo[2.2.1]heptane moiety, and 1,2,4-oxadiazole substituents act as potent and selective DPP-4 inhibitors. By the stereochemical refinement of oxadiazole derivatives of neogliptin, we discovered compound 9a, a strong candidate for further development in T2DM treatment. Full article

Glucagon-like peptide-1 (GLP-1) is a peptide hormone secreted by the small intestine upon food intake. GLP-1 enhances insulin secretion, suppresses glucagon release, and promotes satiety, resulting in reduced food consumption and subsequent weight loss. Endogenous GLP-1 has a very short half-life and is rapidly degraded by the enzyme dipeptidyl-peptidase-IV (DPP-4). To address this limitation, GLP-1 receptor agonists (GLP-1RAs) and DPP-4 inhibitors (DPP-4is) were developed and have demonstrated potency in clinical practice. In recent years, GLP-1RA and DPP4-i therapies are known to have pleiotropic effects, such as a reduction in oxidative stress, autophagy regulation, metabolic reprogramming, enhancement of anti-inflammatory signaling, regulation of gene expression, and being neuroprotective. These effects imply a therapeutic perspective for GLP-1RA and DPP-4i therapies in neuropathic pain treatment. Preclinical and clinical studies increasingly support the hypothesis that these therapies may alleviate neuropathic pain by targeting multiple mechanisms that induce neuropathic pain, such as inflammation, oxidative stress, and mitochondrial dysfunction. This review explores the mechanisms by which GLP-1RAs and DPP-4is alleviate neuropathic pain. It also highlights current advancements in incretin research, focusing on the therapeutic effects of GLP-1RAs and DPP-4-is for neuropathic pain. Full article

The aim of this study was to identify and characterize the bioactive peptide profile of Podolica cow’s milk. This dairy product is known for its nutritional properties related to the presence of peculiar lipids and is a typical breed traditionally reared in southern Italy. Using top-down peptidomics, we identified 2213 peptides in milk samples from four different farms, with 19 matching bioactive sequences. Bioactivities include dipeptidyl peptidase-IV (DPP-IV) inhibition, angiotensin-converting enzyme (ACE) inhibition, antioxidant activity, enhanced calcium uptake, and other peptides with potential antimicrobial effects. DPP-IV-inhibitory peptides (e.g., LDQWLCEKL and VGINYWLAHK) suggest potential for type 2 diabetes management, while ACE inhibitors (such as YLGY and FFVAPFPEVFGK) could support cardiovascular health by reducing hypertension. Antimicrobial peptides such as SDIPNPIGSENSEK and VLNENLLR showed broad spectrum of activity against various harmful microorganisms, positioning Podolica milk as a promising source for natural antimicrobial agents. Additionally, peptides with osteoanabolic, antianxiety, and immunomodulatory properties further highlight the multifaceted health benefits associated with this type of milk. Our findings underline the functional richness of Podolica milk peptides with various bioactivity properties, which could enhance the value of derived dairy products and contribute to sustainable agricultural practices. Future research will aim to explore these bioactivity properties in vivo, establishing a foundation for functional foods and supplements based on Podolica milk. Full article

Dipeptidyl peptidase IV (DPP-IV) is a serine protease whose inhibition has been an object of considerable interest in the context of developing novel treatments for type 2 diabetes mellitus. The development of novel DPP-IV inhibitors from natural or synthetic origin has seen a growing scientific interest in recent years, especially during the SARS-CoV-2 pandemic, when DPP-IV inhibitors were found to be of beneficial therapeutic value for COVID-19 patients. The present manuscript aims to summarize the most recent information on the synthesis of different DPP-IV inhibitors, emphasizing the various heterocyclic scaffolds that can be found in them. Special attention is devoted to DPP-IV inhibitors that are currently in clinical trials. Different synthetic approaches for the construction of DPP-IV inhibitors are discussed, as well as the most recent developments in the field. Full article