Search Results (216)

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

Microbial metabolites offer a multitude of mechanisms for alleviating diabetes, particularly type 2 diabetes (T2D). However, the metabolites of yeasts recognised as safe remain under-explored and are receiving less attention in the treatment of T2D. In addition to the recognised probiotic status of certain yeasts, their genetic feature is responsible for many of the effects observed. Branched and non-branched short-chain fatty acids, bioactive peptides, carotenoids, and polysaccharides (β-glucans, mannans, and peptides derived from them) have vital properties that modulate intestinal permeability, soothe inflammation, and directly influence insulin sensitivity. Their action mechanism ranges from hepatic lipogenesis via the induction of hormone-sensitive lipase and the inhibition of α-glucosidase or DPP-IV to promoting the secretion of GLP-1 (Glucagon-Like Peptide-1) and GIP (Gastric Inhibitory Polypeptide), orchestrating immune modulation, and nourishing the gut microbiota. The richness of the yeast metabolome suggests that a concentrated fermentate could be developed to potentiate the functional effects in vitro in the treatment of T2D. The purpose of this review is to take stock of the current state of knowledge of probiotic yeast metabolites and outline their potential for the treatment of diabetes via the development of food supplements or nutraceuticals. 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

Phycobiliproteins have gained increasing attention for their antidiabetic potential, yet the specific bioactive peptides and their targets and molecular mechanisms have remained unclear. In this study, four peptides with potential hypoglycemic activity were identified through virtual screening. Network pharmacology was employed to elucidate their hypoglycemic mechanism in the treatment of T2DM. A subsequent in vitro assay confirmed that the synthesized peptides, GR-5, SA-6, VF-6, and IR-7, exhibited significant inhibitory activity against α-glucosidase and DPP-IV. In insulin-resistant HepG2 models, all four peptides exhibited no cytotoxicity. Among them, GR-5 demonstrated the most promising therapeutic potential by remarkably enhancing cellular glucose consumption capacity. Furthermore, GR-5 administration substantially increased glycogen synthesis and enzymatic activities of hexokinase and pyruvate kinase with statistically significant improvements compared to the control groups. This study provides novel peptide candidates for T2DM treatment and validates an integrative strategy for targeted bioactive peptide discovery, advancing the development of algal protein-based therapeutics. 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

Coffee silverskin (CS), a by-product generated during coffee roasting, contains high levels of xylan hemicellulose and protein, making it a promising substrate for functional ingredient production. This study developed an integrated bioprocess to simultaneously produce bioactive peptides and xylooligosaccharides (CS-XOS) from CS. Conventional alkaline extraction (CAE) under optimized conditions (1.0 M NaOH, 90 °C, 30 min) yielded 80.64 mg of protein per gram of CS and rendered the solid residue suitable for XOS production. Enzymatic hydrolysis of the extracted protein using protease_SE5 generated low-molecular-weight peptides (0.302 ± 0.01 mg/mL), including FLGY, FYDTYY, and FDYGKY. These peptides were non-toxic, exhibited in vitro antioxidant activity (0–50%), and showed ACE-inhibitory activities of 60%, 26%, and 79%, and DPP-IV-inhibitory activities of 19%, 18%, and 0%, respectively. Concurrently, the alkaline-treated CS solid residue (ACSS) was hydrolyzed using recombinant endo-xylanase, yielding 52.5 ± 0.08 mg of CS-XOS per gram of ACSS. The CS-XOS exhibited prebiotic effects by enhancing the growth of probiotic lactic acid bacteria (μ_max 0.100–0.122 h⁻¹), comparable to commercial XOS. This integrated bioprocess eliminates the need for separate processing lines, enhances resource efficiency, and provides a sustainable strategy for valorizing agro-industrial waste. The co-produced peptides and CS-XOS offer significant potential as functional food ingredients and nutraceuticals. Full article

Rapeseed meal, a byproduct of oil extraction, is increasingly recognised as a valuable source of plant protein and health-promoting peptides. This study aimed to identify key proteins in cold-pressed rapeseed meal and assess their potential to release bioactive peptides through in silico hydrolysis using plant-derived proteases, namely papain, bromelain, and ficin. Proteomic profiling via two-dimensional electrophoresis and MALDI-TOF/TOF mass spectrometry revealed cruciferin as the dominant protein, along with other metabolic and defence-related proteins. In silico digestion of these sequences using the BIOPEP database generated thousands of peptide fragments, of which over 50% were predicted to exhibit bioactivities, including ACE and DPP-IV inhibition, as well as antioxidant, neuroprotective, and anticancer effects. Among the evaluated enzymes, bromelain exhibited the highest efficacy, yielding the greatest quantity and diversity of bioactive peptides. Notably, peptides with antihypertensive and antidiabetic properties were consistently identified across all of the protein and enzyme variants. Although certain rare functions, such as anticancer and antibacterial activities, were observed only in specific hydrolysates, their presence underscores the broader functional potential of peptides derived from rapeseed. These findings highlight the potential of rapeseed meal as a sustainable source of functional ingredients while emphasising the necessity for experimental validation to confirm the predicted bioactivities. Full article

Chicken feathers constitute a major by-product from the poultry industry, with a potential environmental impact and significant difficulties in their management. This study aimed to develop a sustainable method to hydrolyse chicken feathers and evaluate the effects of microwave (MW) irradiation pre-treatment in the generation of bioactive hydrolysates by simple or sequential hydrolysis with Alcalase. The hydrolysate with MW irradiation pre-treatment and Alcalase (2%, 2 h) (MWA) showed the highest overall antioxidant activity and neprilysin-inhibitory activity (55%), whereas samples without MW irradiation pre-treatment exerted the highest inhibitory activity of dipeptidyl peptidase IV (DPP IV) and angiotensin-converting enzyme (ACE-I), with values close to 50 and 70%, respectively. Mass spectrometry in tandem of bioactive hydrolysates was performed, and an in silico approach was used to characterise the obtained sequences. These results confirmed that MW irradiation pre-treatment improved Alcalase hydrolysis, leading to the generation of bioactive peptides with potential multifunctional properties, including antioxidant, antidiabetic, and antihypertensive activities. Moreover, this study highlights the potential of combining MW irradiation and enzymatic hydrolysis as a sustainable strategy for the revalorisation of chicken feathers. Full article

Goat caseins are highly polymorphic proteins that affect milk functional properties. In this study, an in silico approach was employed to analyze the influence of goat casein allelic variants on the quantity and bioactivity potential of peptides released after enzymatic hydrolysis. The reported protein sequences from the most frequent allelic variants in Capra hircus caseins (α-S1, β, α-S2, and κ-casein) were analyzed in the BIOPEP-UWM database to determine the frequency of occurrence of bioactive fragments from each casein. After specific hydrolysis with pepsin, trypsin, and chymotrypsin A, important differences in the peptide profile and bioactivity potential were observed within and between the casein allelic variants. The β-casein A and C alleles, α-S1-casein allele E, and α-S2-casein allele F presented the highest bioactivity potential, and some allele-specific peptides were also released, highlighting the impact of genotype on the predicted bioactivity. The inhibition of angiotensin-converting enzyme (ACE-I) and dipeptidyl peptidase IV (DPP-IV) activities was the most frequent bioactivity of the released peptides, suggesting possible antihypertensive and antidiabetic effects. Once confirmed by experimental studies, the use of goat casein genotyping could direct efforts to enhance the functional quality of goat milk. Full article

Sheep milk is a rich source of bioactive compounds with significant potential in functional foods and biomedical applications. It contains high levels of proteins, peptides, and fatty acids with numerous health-promoting properties for the human body. Key components such as lactoferrin, proline, orotic acid, and conjugated linoleic acid (CLA) support the prevention and treatment of chronic diseases such as diabetes, cardiovascular disease, obesity, cancer, and neurodegenerative disorders. Bioactive peptides from sheep milk regulate blood glucose levels by inhibiting enzymes such as dipeptidyl peptidase-IV (DPP-IV) and α-glucosidase, while conjugated linoleic acid improves lipid metabolism and reduces inflammation. The high-quality proteins in sheep milk are essential for tissue regeneration and maintaining muscle mass, which is particularly beneficial for the elderly and infants who are allergic to cow milk. Recently, there has been an increasing interest in hydrogel dressings enriched with bioactive substances from sheep milk, which support wound healing by supporting collagen synthesis, reducing inflammation, and having antimicrobial properties. Such hydrogels are particularly promising for the treatment of chronic wounds, burns, and diabetic ulcers, making them a valuable tool in regenerative medicine. The aim of this manuscript is to review the current reports on bioactive components of sheep milk and their potential for biomedical applications. 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

Type 2 diabetes mellitus remains a critical global health challenge, driving the pursuit of novel therapeutic strategies. This study investigated the anti-diabetic efficacy of the peptide 1CBR, derived from sodium caseinate hydrolysate, administered orally at 25 mg/kg/day to db/db mice over a 4-week period. Glucose tolerance was evaluated via oral glucose tolerance tests (OGTT), while plasma dipeptidyl peptidase-IV (DPP-IV) activity, glucagon-like peptide-1 (GLP-1), and insulin concentrations were quantified using enzyme-linked immunosorbent assays (ELISA). Two bioactive peptides, GPFPLPD and APDSGNFR, were isolated and characterized, exhibiting half-maximal inhibitory concentrations (IC₅₀) of 99.12 µM and 73.07 µM for DPP-IV inhibition, respectively, and both significantly stimulated GLP-1 secretion in enteroendocrine cells in vitro. Pharmacokinetic analysis in Sprague–Dawley rats demonstrated oral bioavailability of 11.28% and 19.12% for these peptides, surpassing typical expectations for peptide-based agents. Collectively, these results provide compelling evidence that 1CBR-derived peptides exert glucose-lowering effects through the dual mechanisms of DPP-IV inhibition and GLP-1 stimulation, combined with favorable oral absorption profiles. These findings underscore the potential of 1CBR peptides as promising candidates for development into nutraceuticals or pharmaceutical agents for diabetes management. Full article

This work utilized seabuckthorn seed meal protein (SSP) to develop hypoglycemic peptides via controlled protease catalyzed hydrolysis. Among the SSP hydrolysates (SSPHs) obtained by means of various proteases, the SSP hydrolyzed by dispase (SSPD) exhibited extraordinary inhibitory abilities against three key enzymes involved in glucose metabolism: α-glucosidase, α-amylase, and dipeptidyl peptidase-IV (DPP-IV). Following process optimization and purification, SSPD displayed remarkable inhibitions to α-glucosidase (IC₅₀: 3.45 ± 0.18 mg/mL) and DPP-IV (IC₅₀: 5.01 ± 0.21 mg/mL), respectively. Molecular docking analysis and in vitro verification revealed three peptides in the SSPD with α-glucosidase inhibition: FHF, FFI, and FGI (IC₅₀: 3.98 ± 0.16 mM, 8.21 ± 0.21 mM, 11.57 ± 0.20 mM), and three peptides with DPP-IV inhibition: IYF, IGF, and LFF (IC₅₀: 5.32 ± 0.15 mM, 7.17 ± 0.14 mM, 7.62 ± 0.19 mM). These findings demonstrate that SSP holds promise as a significant natural resource for the creation of multifunctional hypoglycemic peptides, which can be utilized in nutritional and functional food applications. Full article

Antarctic krill (Euphausia superba) is a nutrient-rich marine resource. Although several terrestrial proteases have been used to prepare Antarctic krill peptides (AKPs), there has been no report on the preparation of AKPs using a marine protease. Here, marine bacterial protease A69 was used to prepare AKPs with multi-bioactivities. Through optimizing hydrolysis parameters, we established a process for AKPs preparation by hydrolyzing Antarctic krill powder with A69. In the prepared AKPs, peptides less than 3000 Da and 1000 Da accounted for 99.23% and 88.37%, respectively. The scavenging ratios of the AKPs to ABTS⁺, DPPH· and ·OH reached 93.23 ± 0.09%, 99.90 ± 0.15%, and 93.90 ± 0.47%, respectively. The AKPs also had high angiotensin-converting enzyme (ACE)-inhibitory activity, with an IC₅₀ of 0.22 ± 0.04 mg/mL. At 40 mg/mL, the AKPs inhibited α-glucosidase and dipeptidyl peptidase IV (DPP-IV) activities by 7.18% and 13.62%, respectively, and displayed antibacterial activity to Escherichia coli. Moreover, 14 antioxidant peptides, 24 ACE-inhibitory peptides, 2 α-glucosidase-inhibitory peptides, and 10 DPP-Ⅳ-inhibitory peptides were identified from the AKPs. These results demonstrate that the prepared AKPs contain diverse bioactive peptides and have multi-bioactivities. This study indicates that marine bacterial protease A69 has promising application potential in preparing AKPs with multi-bioactivities. 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