Search Results (94)

Gluten-related disorders, including celiac disease (CeD) and non-celiac gluten sensitivity (NCGS), are triggered by the immune response to gluten peptides that resist complete digestion by human gastrointestinal enzymes. Microbial peptidases have emerged as promising biocatalysts capable of degrading these immunogenic peptides, offering potential therapeutic and industrial applications. This review explores the role of microbial peptidases in gluten degradation, highlighting key enzyme families, their mechanisms of action, and their effectiveness in reducing gluten immunogenicity. Additionally, we discuss advances in enzymatic therapy, food processing applications, and the challenges associated with optimizing microbial enzymes for safe and efficient gluten detoxification. Understanding the potential of microbial peptidases in mitigating gluten-related disorders paves the way for novel dietary and therapeutic strategies. Full article

Background: The New Zealand pine bark has been demonstrated in vitro to inhibit digestive enzymes involved in carbohydrate digestion (alpha-amylase, alpha-glucosidase, and dipeptidyl-peptidase 4 (DPP-4)). Objective: This study aims to investigate the inhibitory effects of the New Zealand pine bark on sucrose uptake and glycaemic responses in humans. Methods: A single-blind, randomised, placebo-controlled, crossover trial was carried out involving healthy adults (n = 40 (M: 12, F: 28), 30.1 ± 1.3 years, BMI 23.4 ± 0.5 kg/m², HbA1c 32.5 ± 0.6 mmol/mol, FBG 4.7 ± 0.1 mmol/L). A control (75 g of sucrose powder only), and two doses of the pine bark extract (50 and 400 mg) were provided on separate occasions, with 75 g of sucrose mixed in 250 mL of water. Blood samples were collected at −10, 0, 15, 30, 45, 60, 90, and 120 min via a finger prick test. A linear mixed model for repeated measures (SPSS v30, IBM) was applied, and data presented as model-adjusted mean ± SEM. Results: Compared to control (247.5 ± 14.0 mmol/L⋅min), the iAUCglucose was significantly reduced with the 400 mg dose (211.8 ± 13.9 mmol/L⋅min, 14.4% reduction, and p = 0.037), but not with 50 mg dose (220.8 ± 14.2 mmol/L⋅min, 10.8% reduction, and p = 0.184). Compared to control (9.1 ± 0.2 mmol/L), glucose peak value was significantly reduced with the 50 mg dose (8.6 ± 0.2 mmol/L, 5.5% reduction, and p = 0.016) but not with the 400 mg dose (8.7 ± 0.2 mmol/L, 4.4% reduction, and p = 0.093). There were no statistically significant changes in postprandial insulin levels with the pine bark extract compared to control. Conclusions: The New Zealand pine bark extract attenuated sucrose uptake with improved glycaemic responses, and may therefore be useful as a hypoglycaemic adjunct to the diet. Full article

Background: Camel milk is considered to be an important source of bioactive peptides with potential anti-diabetic effects. However, the mechanism by which these active peptides exert their anti-diabetic effects is not clear. The aim of this study was to systematically evaluate the in vivo anti-diabetic effects of Leucine-Leucine-Proline-Lysine (LLPK), a novel dipeptidyl peptidase-4 (DPP-4) inhibitory peptide identified from the in vitro gastrointestinal digestion product of camel milk. Methods: A db/db diabetic mouse model was used, and LLPK was administered to mice at doses of 50 mg/kg BW and 100 mg/kg BW as a daily oral gavage for 30 days. The effects of LLPK on fasting blood glucose (FBG), oral glucose tolerance test (OGTT), insulin tolerance test (ITT), and serum lipid levels were monitored, and possible mechanisms of action were elucidated using proteomics. Results: The results demonstrated that LLPK significantly improved diabetic symptoms, including FBG, OGTT, ITT, and serum lipid levels in db/db diabetic mice. Furthermore, significantly increased levels of serum glucagon-like peptide 1 (GLP-1) and reduced serum DPP-4 activity were observed in the LLPK-treated group compared to the control group. Hepatic proteomics indicated that LLPK improved glucose and lipid metabolism via the PPAR signaling pathway, where the key targets were Scd1, Acox1, Acaa1b, Slc27a1, Acsl1, and Ehhadh. Conclusions: In summary, this study provided new insights into the anti-diabetic mechanisms of camel milk and supported the development of camel milk-based anti-diabetic functional foods or nutraceuticals. Full article

Bacterial extracellular vesicles (BEVs) produced by members of the intestinal microbiota can not only contribute to digestion but also mediate microbe–host cell communication via the transfer of functional biomolecules to mammalian host cells. An unresolved question is which host factors and conditions influence BEV cargo and how they impact host cell function. To address this question, we analysed and compared the proteomes of BEVs released by the major human gastrointestinal tract (GIT) symbiont Bacteroides thetaiotaomicron (Bt) in vivo in fed versus fasted animals using nano-liquid chromatography with tandem mass spectrometry (LC-MSMS). Among the proteins whose abundance was negatively affected by fasting, nine of ten proteins of the serine protease family, including the regulatory protein dipeptidyl peptidase-4 (DPP-4), were significantly decreased in BEVs produced in the GITs of fasted animals. Strikingly, in extracellular vesicles produced by the intestinal epithelia of the same fasted mice, the proteins with the most increased abundance were serine protease inhibitors (serpins). Together, these findings suggest a dynamic interaction between GI bacteria and the host. Additionally, they indicate a regulatory role for the host in determining the balance between bacterial serine proteases and host serpins exported in bacterial and host extracellular vesicles. Full article

Dipeptidyl peptidase IV (DPP-IV) inhibitory peptides have emerged as promising functional ingredients for managing type 2 diabetes due to their ability to enhance insulin secretion and improve glycemic control. This review provides a concise overview of current strategies for the preparation and encapsulation of DPP-IV inhibitory peptides, with a focus on food industry application, evaluating bioinformatics for substrate selection, and methods like mild enzymatic hydrolysis, cost-effective fermentation, and high-purity chemical synthesis for peptide production. Challenges associated with incorporating these peptides into food products are addressed, including impacts on sensory properties, stability during processing and digestion, and the need for effective delivery systems to enhance bioavailability. Potential solutions to improve peptide stability and targeted release, such as emulsions, liposomes, and nanoparticles, are explored. Future research directions are outlined, emphasizing the necessity for scalable production methods, co-encapsulation strategies, and consumer acceptance studies to facilitate the commercialization of DPP-IV inhibitory peptides as functional food ingredients. By addressing these key areas, this review aims to provide a theoretical foundation and practical guidance for the development of DPP-IV inhibitory peptides, paving the way for their broader application in the prevention and management of type 2 diabetes. Full article

Colostrum is essential for the survival and development of newborn mammals. This primary source of nourishment during the first days of infant life is rich in functional components conductive to the enhancement of neonate immunity and growth. Compared with mature milk, a higher protein and peptide content is observed in colostrum, whilst it is low in fat and carbohydrates. The functional properties of colostrum are closely linked to the release of bioactive peptides during the gastrointestinal digestion of colostrum proteins. Our study aimed to comprehensively analyze the whey proteome of colostrum from indigenous Greek goats and to examine the influence of bioactive peptides released during digestion on human metabolism. Colostrum and mature milk samples from healthy ewes were subjected to nanoLC-MS/MS analysis, revealing differentially expressed proteins. These proteins were functionally characterized and subjected to in silico digestion. Using machine learning models, we classified the peptide functional groups, while molecular docking assessed the binding affinity of the proposed angiotensin-converting enzyme (ACE)- and dipeptidyl peptidase IV (DPPIV)-inhibitory peptides to their target molecules. A total of 898 proteins were identified in colostrum, 40 of which were overexpressed compared with mature milk. The enzymatic cleavage of upregulated proteins by key gastrointestinal tract proteases and the downstream analysis of peptide sequences identified 117 peptides predicted (with >80% confidence) to impact metabolism, primarily through modulation of the renin–angiotensin system, insulin secretion, and redox pathways. This work advances our understanding of dietary bioactive peptides and their relevance to human metabolism, highlighting the potential health benefits of colostrum consumption. Full article

Lupin (Lupinus angustifolius L.) proteins are potential sources of bioactive peptides (LBPs) that can inhibit dipeptidyl peptidase IV (DPP-IV) and angiotensin I-converting enzyme (ACE-I) activity. However, the capacity of different enzymes to release LBPs, the pharmacokinetic and bioactivities of the peptides released, and their binding affinities with the active sites of DPP-IV and ECA-I are topics scarcely addressed. Therefore, we used in silico hydrolysis (BIOPEP-UWM platform) with various enzymes to predict the release of LBPs. Among the bioactive peptides identified in lupin proteins (n = 4813), 2062 and 1558 had DPP-IV and ACE-I inhibitory activity, respectively. Ficin, bromelain, and papain released the highest proportion of ACE-I (n = 433, 411, and 379, respectively) and DPP-IV (n = 556, 544, and 596, respectively) inhibitory peptides. LBPs with favorable pharmacokinetics and gastrointestinal stability tightly interacted with the active sites of ACE-I (–5.6 to –8.9 kcal/mol) and DPP-IV (–5.4 to –7.6 kcal/mol). Papain generated the most bioavailable LBPs (n = 459) with ACE-I (n = 223) and DPP-IV (n = 412) inhibitory activity. These peptides were non-toxic and gastrointestinal digestion stable. Notably, papain-based hydrolysis released some LBPs (n = 270) that inhibited both ACE-I and DPP-IV. Plant protease-based hydrolysis is a promising approach for producing lupin hydrolysates with ACE-I and DPP-IV inhibitory activities. Full article

Garambullo fruit (Myrtillocactus geometrizans) is a rich source of phytochemical compounds that exhibit antioxidant, anti-hyperglycemic, and anti-inflammatory activities, helping to prevent diseases associated with oxidative stress. The objective of this study was to evaluate phenolic compound (PC), betalain (BL), betaxanthin (BX), and betacyanin (BC) contents, and in vitro biological activities (antioxidant, anti-hyperglycemic, and anti-inflammatory) in microencapsulated garambullo extract during in vitro gastrointestinal digestion and storage. Microencapsulation was performed using spray drying. Arabic Gum (GA, 10% in feed solution) and soy protein isolate (SPI, 7% in feed solution) were used as wall materials. After in vitro digestion, the microcapsules (GA, SPI) exhibited higher bioaccessibility (p ≤ 0.05) of PC, BL, BX, and BC, and higher antioxidant activity (AA), compared to the non-encapsulated extract. Both microcapsules showed bioaccessibility in anti-hyperglycemic activity: α-amylase (GA: 90.58%, SPI: 84.73%), α-glucosidase (GA: 76.93%, SPI: 68.17%), and Dipeptidyl peptidase-4 (DPP-4) (GA: 52.81%, SPI: 53.03%); and in anti-inflammatory activity: cyclooxygenase-1 (COX-1) (GA: 78.14%, SPI: 77.90%) and cyclooxygenase-2 (COX-2) (GA: 82.77%, SPI: 84.99%). During storage, both microcapsules showed a similar trend with a significant decrease (p ≤ 0.05) in PC (GA: 39.29%, SPI: 39.34%), BL (GA: 21.17%, SPI: 21.62%), BX (GA: 23.89%, SPI: 23.45%), BC (GA: 19.55%, SPI: 19.84%), and AA (GA: 41.59%, SPI: 42.51%) after 60 days at 30 °C. Both microcapsules retained anti-hyperglycemic activity evaluated by the inhibitory activity of α-amylase (GA: 68.84%, SPI: 70.18%), α-glucosidase (GA: 59.93%, SPI: 58.69%), and DPP-4 (GA: 52.81%, SPI: 53.01%), and anti-inflammatory activity evaluated by the inhibitory activity of COX-1 (GA: 82.18%, SPI: 82.81%) and COX-2 (GA: 81.11%, SPI: 81.08%). Microencapsulation protected the phytochemical compounds and in vitro biological activities by allowing controlled release during in vitro digestion compared to the non-encapsulated extract. However, after 60 days storage at 30 °C, 60% of PC and AA, 80% of BL, BX, and BC, and 20–45% of the anti-hyperglycemic and anti-inflammatory activity were lost. Full article

Background/Objectives: Type 2 diabetes (T2D) has become a critical global health issue, with an increasing prevalence that contributes to significant morbidity and mortality. Inhibiting dipeptidyl peptidase-IV (DPP4) is a promising strategy for managing T2D. This study aimed to explore the DPP4 inhibitory peptide derived from bitter melon seed protein (BMSP) hydrolysate. Methods: Reversed-phase high-performance liquid chromatography (RP-HPLC) was utilized to fractionate the hydrolysate. Peptide in the highest activity fraction was analyzed using liquid chromatography-mass spectrometry (LC-MS/MS). Peptide synthetic was used for further characterizations, such as bioactivity exploration, inhibition mechanism, molecular docking, and peptide stability against in vitro simulated gastrointestinal (SGI) digestion. Results: The BMSP hydrolysate was digested with gastrointestinal proteases (GP) and assessed for DPP4 inhibitory activity, yielding an IC₅₀ of 1448 ± 105 μg/mL. Following RP-HPLC fractionation, MPHW (MW4) and VPSGAPF (VF7) were identified from fraction F8 with DPP4 IC₅₀ values of 128.0 ± 1.3 µM and 150.6 ± 3.4 µM, respectively. Additionally, MW4 exhibited potential antihypertensive effects through ACE inhibition with an IC₅₀ of 172.2 ± 10.6 µM. The inhibitory kinetics and molecular docking simulations indicated that both MW4 and VF7 were competitive inhibitors of DPP4, while MW4 was also a competitive inhibitor of ACE. Importantly, both peptides remained stable during simulated gastrointestinal digestion, suggesting their resistance to human digestive processes and their capacity to maintain biological activity. Conclusions: The findings suggest that BMSP-GP hydrolysate may have potential in terms of the development of health foods or therapeutic agents. However, in vivo studies are also essential for further confirmation of efficacy. Full article

Studies have shown that corn (Zea mays L.) proteins, mainly α-zein, have the potential to act on therapeutic targets related to non-communicable chronic diseases, such as high blood pressure and type 2 diabetes. Enzymatic hydrolysis of proteins present in foods can result in a great diversity of peptides with different structures and possible bioactivities. A review of recent scientific research papers was performed to show evidence of the bioactive properties of corn peptides by in vitro assays. The α-zein amino acid sequences were identified in the UniProtKB protein database and then analyzed in the BIOPEP database to simulate enzymatic digestion and verify the potential biological action of the resulting peptides. The peptides found in the BIOPEP database were categorized according to the probability of presenting biological action using the PeptideRanker database. The aim was to use existing data to identify in silico the potential for obtaining biologically active peptides from α-zein, the main storage protein of corn. The analysis showed that the majority of peptide fragments were related to the inhibition of angiotensin-converting enzyme, followed by the inhibition of dipeptidyl peptidase IV and dipeptidyl peptidase III. Many drugs used to treat high blood pressure and type 2 diabetes work by inhibiting these enzymes, suggesting that corn peptides could be potential alternative agents. In vitro studies found that the primary bioactivity observed was antioxidative action. Both in vitro and in silico approaches are valuable for evaluating the bioactive properties resulting from protein hydrolysis, such as those found in α-zein. However, conducting in vitro studies based on prior in silico evaluation can be more efficient and cost-effective. Full article

This study investigates the production of protein hydrolysates with dipeptidyl peptidase-IV (DPP-IV) inhibitory activity from agro-industrial by-products, namely olive seed, sunflower seed, rapeseed, and lupin meals, as well as from two plant protein isolates such as pea and potato. Furthermore, the effect of simulated gastrointestinal digestion on the DPP-IV inhibitory activity of all the hydrolysates was evaluated. Overall, the lowest values of IC₅₀ (1.02 ± 0.09 – 1.24 ± 0.19 mg protein/mL) were observed for the hydrolysates with a high proportion of short-chain [< 1 kDa] peptides (i.e., olive seed, sunflower seed, and lupin) or high content of proline (i.e., rapeseed). Contrarily, the IC₅₀ of the pea and potato hydrolysates was significantly higher (1.50 ± 0.13 – 1.93 ± 0.13 mg protein/mL). In vitro digestion led to an increase in peptides <1 kDa for almost all hydrolysates (except olive and sunflower seed meals), which was noticeable for rapeseed, pea, and potato hydrolysates. Digestion did not significantly modify the DPP-IV inhibitory activity of olive, sunflower, rapeseed, and potato hydrolysates, whereas a significant decrease in IC₅₀ value was obtained for pea hydrolysate and a significant increase in IC₅₀ was obtained for lupin hydrolysate. Thus, this work shows the potential of agro-industrial by-products for the production of protein hydrolysates exhibiting DPP-IV inhibition. Full article

An insect’s gut microbiome is an essential “organ” in their life cycle, playing a crucial role by aiding food digestion and nutrient absorption. This study employed both culture-independent and culture-dependent methods to explore the protease resources present in the gut of the omnivorous insect Gryllotalpa orientalis. The findings revealed that the gut extract of G. orientalis contained a diverse array of proteases, including cysteine proteases, pepsin, serine proteases, and trypsin, as well as some unidentified proteases. Furthermore, the protease gene htpX, derived from gut bacterium Priestia megaterium DX-3, has been cloned and recombinantly expressed. The recombinant DX-3-htpX protease exhibited a 61.9-fold increase in fermentation level compared to the DX-3 protease. This protease was characterized as a neutral, heat-resistant metalloprotease with an M48 peptidase domain, and it was observed that the binding of Ca²⁺ to the recombinant protease resulted in the formation of the largest active pocket. This study provides technical support for further development and utilization of functional protein resources in insect gut. Full article

Aspergillus fungi constitute a pivotal element within ecosystems, serving as both contributors of biologically active compounds and harboring the potential to cause various diseases across living organisms. The organism’s proteolytic enzyme complex, termed the degradome, acts as an intermediary in its dynamic interaction with the surrounding environment. Using techniques such as genome and transcriptome sequencing, alongside protein prediction methodologies, we identified putative extracellular peptidases within Aspergillus ochraceus VKM-F4104D. Following manual annotation procedures, a total of 11 aspartic, 2 cysteine, 2 glutamic, 21 serine, 1 threonine, and 21 metallopeptidases were attributed to the extracellular degradome of A. ochraceus VKM-F4104D. Among them are enzymes with promising applications in biotechnology, potential targets and agents for antifungal therapy, and microbial antagonism factors. Thus, additional functionalities of the extracellular degradome, extending beyond mere protein substrate digestion for nutritional purposes, were demonstrated. Full article

The study aimed to uncover the molecular response of juvenile Sebastes schlegelii to air exposure stress by identifying differentially expressed genes (DEGs) that may underlie their anti-stress mechanisms. Juvenile Sebastes schlegelii were subjected to varying durations of air exposure stress. The total RNA was extracted from whole tissues and sequenced using the Illumina NovaSeq 6000 platform. The transcriptome data were analyzed to identify DEGs through pairwise comparisons across a control group and two experimental groups exposed to air for 40 s and 2 min 30 s, respectively. The comparative DEG analysis revealed a significant number of transcripts responding to air exposure stress. Specifically, 5173 DEGs were identified in the 40 s exposure group (BS) compared to the control (BC), 6742 DEGs in the 2 min 30 s exposure group (BD) compared to the control (BC), and 2653 DEGs when comparing the BD to the BS group. Notably, Gene Ontology (GO) analysis showed an enrichment of DEGs associated with peptidase activity and extracellular regions, suggesting a role in the organism’s stress response. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis pointed to the involvement of metabolic pathways, which are crucial for energy management under stress. The upregulation of protein digestion and absorption pathways may indicate a physiological adaptation to nutrient scarcity during stress. Additionally, the identification of antibiotic biosynthesis pathways implies a potential role in combating stress-induced infections or damage. The identified DEGs and enriched pathways provide insights into the complex anti-stress response mechanisms in juvenile Sebastes schlegelii. The enrichment of peptidase activity and extracellular region-related genes may reflect the initiation of tissue repair and immune response following air exposure. The connection between protein digestion and absorption pathways and anti-stress capabilities could be interpreted as a metabolic readjustment to prioritize energy-efficient processes and nutrient assimilation during stress. The role of antibiotic biosynthesis pathways suggests a defensive mechanism against oxidative stress or microbial invasion that might occur with air exposure. Full article

With the global increase in hyperglycemia and hyperlipidemia, there is an urgent need to explore dietary interventions targeting the inhibition of dipeptidyl peptidase-IV (DPP-IV) and lipid digestion and absorption. This study investigated how Lactobacillus rhamnosus GG (LGG) affects various aspects of black goji berry (BGB) (Lycium ruthenicum Murr.) juice, including changes in physicochemical and functional properties, as well as microbiological and sensory attributes. Throughout the fermentation process with 2.5–10% (w/v) BGB, significantly improved probiotic viability, lactic acid production, and decreased sugar content. While total flavonoids increase, anthocyanins decrease, with no discernible change in antioxidant activities. Metabolite profiling reveals elevated phenolic compounds post-fermentation. Regarding the inhibition of lipid digestion and absorption, fermented BGB exhibits improved bile acid binding, and disrupted cholesterol micellization by approximately threefold compared to non-fermented BGB, while also increasing pancreatic lipase inhibitory activity. Furthermore, a decrease in cholesterol uptake was observed in Caco-2 cells treated with fermented BGB (0.5 mg/mL), with a maximum reduction of 16.94%. Fermented BGB also shows more potent DPP-IV inhibition. Sensory attributes are significantly improved in fermented BGB samples. These findings highlight the potential of BGB as a bioactive resource and a promising non-dairy carrier for LGG, enhancing its anti-hyperglycemic and anti-hyperlipidemic properties. Full article