Cathepsin B-Activatable Bioactive Peptide Nanocarrier for High-Efficiency Immunotherapy of Asthma.

Introduction: Asthma, a chronic respiratory disease closely associated with inflammation, presents ongoing treatment challenges. IALLIPF (le-Ala-Leu-Leu-Ile-Pro-Phe) is one of millet prolamins peptides (MPP) which shows anti-oxidant bioactivity by reducing the production of reactive oxygen species (ROS). Tryptophan (Trp, W) is an amino acid that has been demonstrated to possess anti-inflammatory effects. We introduce a novel cathepsin B-activatable bioactive peptides nanocarrier, PEG-IALLIPF-GFLG-W (MPP-Trp), designed for immunotherapy of asthma. Methods: MPP-Trp is synthesized, purified, and its characteristics are investigated by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The yield of nitric oxide (NO) and pro-inflammatory cytokines (TNF-α, IL-6 and IL-1ß) are examined to evaluate anti-inflammatory effects of IALLIPF, Trp and MPP-Trp. The immunomodulatory effects of IALLIPF, Trp and MPP-Trp on Th1/Th2 cell populations and cytokines are investigated by flow cytometry, qRT-PCR and ELISA assays. We explore the therapeutic effect of MPP-Trp in the mouse model of asthma by the analysis of lung histology and ELISA. It is necessary to study the biocompatibility of MPP-Trp by CCK8 assay and histopathologic analysis using hematoxylin and eosin (HE) staining. Results: In asthmatic peripheral blood mononuclear cells (PBMCs), IALLIPF, Trp and MPP-Trp are able to significantly alleviate inflammation by inhibiting the yield of nitric oxide (NO) and pro-inflammatory cytokines (TNF-α, IL-6 and IL-1ß), especially MPP-Trp. MPP-Trp significantly upregulates Th1 cell levels while notably reducing Th2 cell levels. Furthermore, MPP-Trp effectively elevates the expression and production of interferon-gamma (IFN-γ), an essential cytokine from Th1 cells. Additionally, MPP-Trp markedly diminishes the mRNA expression and levels of key asthma pathogenesis cytokines, such as interleukin-4 (IL-4), interleukin-13 (IL-13), and interleukin-5 (IL-5), in asthma PBMCs. MPP-Trp ameliorates pulmonary pathological alterations and significantly inhibits OVA-induced inflammation in mice with asthma. It has little influence on the cell viability in Asthma-PBMCs treated with various concentrations or durations of MPP-Trp. No pathological changes, including in the heart, liver, spleen, lung, and kidney tissues, are observed in non-sensitized and non-challenged mice treated with MPP-Trp (20 mg/kg). Discussion: Our research demonstrates that MPP-Trp has immunomodulatory effects on Th1/Th2 cell populations, essential in managing asthma. It considerably alleviates OVA-induced asthma by shifting the immune response towards a Th1-dominant profile, thereby reducing Th2-driven inflammation. Therefore, this novel bioactive peptide nanocarrier, MPP-Trp, holds promise as a candidate for asthma immunotherapy.

Evaluating intestinal absorption of peptide Met-Lys-Pro in casein hydrolysate using Caco-2 and human iPS cell-derived small intestinal epithelial cells.

High blood pressure is a major risk factor for cardiovascular disease. Our previous study confirmed that daily intake of casein hydrolysate that contained Met-Lys-Pro (MKP) can safely lower mildly elevated blood pressure. The present study aimed to evaluate the intestinal absorption differences between peptide MKP as a casein hydrolysate and synthetic MKP alone using Caco-2 cells and human iPS cell-derived small intestinal epithelial cells (hiSIECs). MKP was transported intact through Caco-2 cells and hiSIECs with permeability coefficient (Papp) values of 0.57 ± 0.14 × 10-7 and 1.03 ± 0.44 × 10-7 cm/s, respectively. This difference in Papp suggests differences in the tight junction strength and peptidase activity of each cell. Moreover, the transepithelial transport and residual ratio of intact MKP after adding casein hydrolysate containing MKP was significantly higher than that after adding synthetic MKP alone, suggesting that other peptides in casein hydrolysate suppressed MKP degradation and increased its　transport. These findings suggest that hiSIECs could be useful for predicting the human intestinal absorption of bioactive peptides; ingesting MKP as a casein hydrolysate may also improve MKP bioavailability.

Dipeptide PA3264 derived from rare and endangered Squama Manis is a novel bioactive peptide for the treatment of triple-negative breast cancer.

BACKGROUND: Squama Manis is a valuable traditional Chinese medicine with a long history of medicinal use in the treatment of breast-related diseases. However, owing to the excessive exploitation and utilization of the resources, Squama Manis has been included in the list of rare and endangered wild animals. The conservation of the resources of Squama Manis and continuing its clinical application has become an urgent problem, and the search for small-molecule substitutes for Squama Manis is an effective way to achieve this goal. Previous studies have identified PA3264 as a possible active ingredient in Squama Manis. In this study, we systematically investigated the pharmacological effects and mechanisms of PA3264 in the treatment of triple-negative breast cancer (TNBC), a representative breast-related disease. METHODS: Cell viability and colony formation assays were performed after treatment with the target dipeptide PA3264 in vitro. Next, 4T1 orthotopic tumors and humanized PBMC-CDX mouse models were generated to examine the antitumor effect of PA3264 in vivo. Transcriptome sequencing and molecular docking experiments were performed to predict pathways to function. Western blotting and quantitative real-time PCR were used to validate the molecular mechanisms underlying the anticancer effects of PA3264. RESULTS: PA3264 significantly inhibited cell viability and migration of breast cancer cells in vitro. Furthermore, PA3264 suppressed the tumor size and reduced the tumor weight in vivo. Finally, it was verified that PA3264 prevented the progression of breast cancer by inhibiting the PI3K/AKT/NF-κB pathway, causing cell cycle arrest, and promoting apoptosis. CONCLUSIONS: This study elucidated that PA3264 derived from rare and endangered Squama Manis was a novel bioactive peptide for treating triple-negative breast cancer from a scientific research perspective.

Protein identification and potential bioactive peptides from pumpkin (Cucurbita maxima) seeds.

Pumpkin is an economically important crop all over the world. Approximately, 18%-21% of pumpkins, consisting of peels and seeds by-products, are wasted during processing. In addition, the seeds are rich in protein and have the potency of bioactive peptide production. This study aims to recognize the proteins and investigate the potential bioactive peptides from pumpkin (Cucurbita maxima) seeds. Pumpkin seeds were subjected to hot air drying (HAD) at 55°C for 12 h and freeze-drying (FD) at -80°C for 54 h before they were powdered, analyzed, and precipitated by isoelectric point to obtain pumpkin seed protein isolates (PSPI). PSPI comprised 11S globulin subunit beta, 2S seed storage albumin, and chaperonin CPN60-1. To generate hydrolysate peptides, PSPI was hydrolyzed using papain, pepsin, and bromelain. FD group pepsin hydrolysates had the highest peptide content of 420.83 mg/g. ACE inhibition and DPP-IV inhibition activity were analyzed for each enzymatic hydrolysate. The pepsin hydrolyzed sample exhibited the highest ACE inhibition of 70.26%, and the papain hydrolyzed sample exhibited the highest DPP-IV inhibition of 30.51%. The simulated gastrointestinal digestion (SGID) conducted by pepsin and pancreatin increased ACE inhibitory activity from 76.93% to 78.34%, and DPP-IV inhibited activity increased from 58.62% to 77.13%. Pepsin and papain hydrolysates were fractionated using ultrafiltration to measure ACE and DPP-IV inhibition activity. The highest free radical scavenging abilities were exhibited by the <1 kDa hydrolysate fractions with 78.34% ACE inhibitory activities and 79.55% DPP-IV inhibitory activities. This research revealed that pumpkin seeds had the potency to produce bioactive peptides.

Exploring the impact of encapsulation on the stability and bioactivity of peptides extracted from botanical sources: trends and opportunities.

Bioactive peptides derived from plant sources have gained significant attention for their potential use in preventing and treating chronic degenerative diseases. However, the efficacy of these peptides depends on their bioaccessibility, bioavailability, and stability. Encapsulation is a promising strategy for improving the therapeutic use of these compounds. It enhances their stability, prolongs their shelf life, protects them from degradation during digestion, and enables better release control by improving their bioaccessibility and bioavailability. This review aims to analyze the impact of various factors related to peptide encapsulation on their stability and release to enhance their biological activity. To achieve this, it is necessary to determine the composition and physicochemical properties of the capsule, which are influenced by the wall materials, encapsulation technique, and operating conditions. Furthermore, for peptide encapsulation, their charge, size, and hydrophobicity must be considered. Recent research has focused on the advancement of novel encapsulation methodologies that permit the formation of uniform capsules in terms of size and shape. In addition, it explores novel wall materials, including polysaccharides derived from unconventional sources, that allow the precise regulation of the rate at which peptides are released into the intestine.

Ovomemolins: Egg-derived peptides that improved cognitive decline after oral administration in mice.

Eggs not only contain all the molecules necessary to nurture new life but are also rich in nutrients such as high-quality protein. For example, epidemiologic studies have shown that egg intake is positively correlated with cognitive function. Thus, we specifically examined the effect of ovalbumin, a major protein present in egg whites, on cognitive function. First, we found that an orally administered enzymatic digest of ovalbumin improves cognitive function in mice fed a high-fat diet. Then, we narrowed down candidate peptides based on the prediction of peptide production according to enzyme-substrate specificity and comprehensive peptide analysis of the digest. We found that three peptides, namely ILPEY, LYRGGLEP, and ILELP, improve cognitive function after oral administration. We also showed that ILPEY, LYRGGLEP, and ILELP were present in the digest and named them ovomemolins A (OMA), B, and C, respectively. Notably, ovomemolins are the first peptides derived from egg whites that have been shown to improve cognitive function. The cognitive improvement induced by OMA, the most abundant of the peptides in the digest, was inhibited by methyllycaconitine, an antagonist of α7nAChR, which is known to be related to memory. These results suggest that OMA improves cognitive function through the acetylcholine system. After OMA administration, brain-derived neurotrophic factor (BDNF) mRNA expression and the number of 5-bromo-2'-deoxyuridine-positive cells suggested that OMA increases hippocampal BDNF expression and neurogenesis.

Hypoglycemic Ability of Sericin-Derived Oligopeptides (SDOs) from Bombyx mori Yellow Silk Cocoons and Their Physiological Effects on Streptozotocin (STZ)-Induced Diabetic Rats.

Patients with diabetes require daily medication to maintain blood sugar levels. Nevertheless, the long-term use of antidiabetics can lose efficacy and cause degeneration in some patients. For long-term diabetes care, integrating natural dietary foods and medicine is being considered. This study investigated the impact of SDOs on blood sugar levels and their physiological effects on diabetic rats. We induced diabetes in male Wistar rats with STZ (50 mg/kg) and then administered an oral glucose tolerance test to determine the SDO dosage comparable to glibenclamide. The rats were divided into nine groups: normal, diabetic, and diabetic with insulin (10 U/kg), glibenclamide (0.6 mg/kg), bovine serum albumin (BSA; 200 mg/kg), soy protein isolate (200 mg/kg), or SDOs (50, 100, and 200 mg/kg). Diabetic rats administered SDOs had a higher body weight and serum insulin but a lower blood sugar than diabetic control rats. Biochemical assays indicated lower AST/SGOT, ALT/SGPT, BUN, and triglycerides but higher HDL in the SDO groups. Immunohistochemistry showed that SDOs reduced damaged islet cells, increased beta-cell size, and improved insulin levels while decreasing alpha cell size and glucagon. The vascular effects of SDOs were like those of normal control treatment and insulin treatment in diabetic rats. SDOs, a yellow silk protein, show potential for long-term diabetes care.

Small Structural Differences in Proline-Rich Decapeptides Have Specific Effects on Oxidative Stress-Induced Neurotoxicity and L-Arginine Generation by Arginosuccinate Synthase.

INTRODUCTION: The proline-rich decapeptide 10c (Bj-PRO-10c; ENWPHPQIPP) from the Bothrops jararaca snake modulates argininosuccinate synthetase (AsS) activity to stimulate L-arginine metabolite production and neuroprotection in the SH-SY5Y cell line. The relationships between structure, interactions with AsS, and neuroprotection are little known. We evaluated the neuroprotective effects of Bj-PRO-10c and three other PROs (Bn-PRO-10a, Bn-PRO-10c > Bn-PRO-10a-MK > Bn-PRO-10a. The structure of PROs and their correlations with enzyme activity revealed that histidine (H5) and glutamine (Q7) in Bj-PRO-10c potentiated their affinity for AsS. CONCLUSIONS: Our investigation provides the first insights into the structure and molecular interactions of PROs with AsS, which could possibly further their neuropharmacological applications.

Rice bran active peptide (RBAP) inhibited macrophage differentiation to foam cell and atherosclerosis in mice via regulating cholesterol efflux.

BACKGROUND: Atherosclerosis is a long-lasting inflammatory condition affecting the walls of arteries, marked by the buildup of fats, plaque formation, and vascular remodeling. Recent findings highlight the significance of cholesterol removal pathways in influencing atherosclerosis, yet the connection between cholesterol removal and regulation of macrophage inflammation remains poorly understood. RBAP could serve as an anti-inflammatory agent; however, its role in atherosclerosis and the mechanism behind it are still not well understood. PURPOSE: The objective of this research is to explore how RBAP impacts cholesterol efflux, which is a considerable element in the advancement of atherosclerosis. METHODS: An atherosclerosis mouse model was established by using an ApoE KO strain mouse on a high-fat diet (HFD) to assess the effects of RBAP, conducted either orally or through injection. Additionally, in vitro experiments were conducted where the induction of THP-1 cells was conducted for the differentiation towards macrophages, and along with mouse RAW264.7 cells, were challenged with ox-LDL to evaluate the impact of RBAP. RESULTS: In this study, RBAP was found to reduce the production and downregulate TNF-α, IL-1ß, and IL-6 levels and inhibited the activation of the TLR4/MyD88/NF-κB signaling in atherosclerosis model mice, as well as in ox-LDL-challenged THP-1 cells and mouse RAW264.7 macrophages. RBAP's effectiveness also improved the enhancement of reverse cholesterol transport (RCT) and cholesterol removal to HDL and apoA1 by increasing the activity of genes related to cholesterol removal PPARγ/LXRα/ABCA1/ABCG1, both in ApoE-/- mice and in THP-1 cells and mouse RAW264.7 macrophages. Notably, RBAP exerted similar effects on atherosclerosis model mice and macrophages to those of TAK-242, an inhibitor of the TLR4 signaling. When RBAP and TAK-242 were applied simultaneously, the improvement was not enhanced compared with either RBAP or TAK-242 treatment alone. CONCLUSION: These findings suggest that RBAP, as a TLR4 inhibitor, has anti-atherosclerotic effects by improving inflammation and promoting cholesterol effection, indicating its therapeutic potential in intervening atherosclerosis.

Microalgal proteins: Unveiling sustainable alternatives to address the protein challenge.

Recent breakthroughs emphasized the considerable potential of microalgae as a sustainable protein source. Microalgae are regarded as a substitute for protein-rich foods because of their high protein and amino acid content. However, despite their nutritional value, microalgae cannot be easily digested by humans due to the presence of cell walls. In the subsequent sections, protein extraction technology, the overview of the inherent challenges of the process, and the summary of the factors affecting protein extraction and utilization have been deliberated. Moreover, the review inspected the formation of proteolytic products, highlighting their diverse bioactivities, including antioxidant, antihypertensive, and immunomodulatory activities. Finally, the discussion extended to the emerging microalgal protein sourced foods, such as baked goods and nutritional supplements, as well as the sensory and marketing challenges encountered in the production of microalgal protein foods. The lack of consumer awareness about the health benefits of microalgae complicates its acceptance in the market. Long-standing challenges, such as high production costs, persist. Currently, multi-product utilization strategies are being developed to improve the economic viability of microalgae. By integrating economic, environmental, and social factors, microalgae protein can be sustainably developed to provide a reliable source of raw materials for the future food industry.

Introducing Bacillus natto and Propionibacterium shermanii into soymilk fermentation: A promising strategy for quality improvement and bioactive peptide production during in vitro digestion.

Herein, the texture properties, polyphenol contents, and in vitro protein digestion characteristics of soymilk single- or co-fermented by non-typical milk fermenter Bacillus natto (B. natto), Propionibacterium freudenreichii subsp. shermanii (P. shermanii), and traditional milk fermenter were evaluated. Co-fermenting procedure containing B. natto or P. shermanii could raise the amounts of gallic acid, caffeic acid, and GABA when compared to the unfermented soymilk. Co-fermented soymilk has higher in vitro protein digestibility and nutritional protein quality. Through peptidomic analysis, the co-work of P. shermanii and Lactobacillus plantarum (L. plantarum) may release the highest relative percentage of bioactive peptides, while the intervention of B. natto and Streptococcus thermophilus (S. thermophilus) resulted in more differentiated peptides. The multi-functional bioactive peptides were mainly released from glycine-rich protein, ß-conglycinin alpha subunit 1, and ACB domain-containing protein. These findings indicated the potential usage of B. natto/S. thermophilus or P. shermanii/L. plantarum in bio-enhanced soymilk fermentation.

Effects of vegetative propagation on protein content and bioactivity of the red seaweed Palmaria palmata.

Production of the red seaweed Palmaria palmata is currently hindered by a lack of standardised cultivation methods leading to uncertainties in yield and product quality. This study assessed vegetative propagation of meristematic fragments and the protein content and bioactivity potential of resulting plants. Growth was strong and sustained, averaging 5% day-1. Total protein contents initially decreased but recovered as the fragments grew larger and thicker. Samples displayed the highest antioxidant activity early in the experiment, suggesting that wounds may increase the secretion of antioxidant compounds. In silico analysis identified 762 potentially bioactive motifs, including 70 matching in vitro results. The newly discovered peptide SLLYSDITRPGGNMYTTR (SR18), linked to the pigment allophycocyanin, had very strong antioxidant properties and may drive the recorded in vitro activity. Vegetative propagation appears as a strong potential cultivation tool, and the utilised approach can be applied to assess the cultivation and nutritional potential of other seaweed species.

Classification of bioactive peptides: A systematic benchmark of models and encodings.

Bioactive peptides are short amino acid chains possessing biological activity and exerting physiological effects relevant to human health. Despite their therapeutic value, their identification remains a major problem, as it mainly relies on time-consuming in vitro tests. While bioinformatic tools for the identification of bioactive peptides are available, they are focused on specific functional classes and have not been systematically tested on realistic settings. To tackle this problem, bioactive peptide sequences and functions were here gathered from a variety of databases to generate a unified collection of bioactive peptides from microbial fermentation. This collection was organized into nine functional classes including some previously studied and some unexplored such as immunomodulatory, opioid and cardiovascular peptides. Upon assessing their sequence properties, four alternative encoding methods were tested in combination with a multitude of machine learning algorithms, from basic classifiers like logistic regression to advanced algorithms like BERT. Tests on a total of 171 models showed that, while some functions are intrinsically easier to detect, no single combination of classifiers and encoders worked universally well for all classes. For this reason, we unified all the best individual models for each class and generated CICERON (Classification of bIoaCtive pEptides fRom micrObial fermeNtation), a classification tool for the functional classification of peptides. State-of-the-art classifiers were found to underperform on our realistic benchmark dataset compared to the models included in CICERON. Altogether, our work provides a tool for real-world peptide classification and can serve as a benchmark for future model development.

Targeting Nrf2 by bioactive peptides alleviate inflammation: expanding the role of gut microbiota and metabolites.

Inflammation is a complex process that usually refers to the general response of the body to the harmful stimuli of various pathogens, tissue damage, or exogenous pollutants. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates cellular defense against oxidative damage and toxicity by expressing genes related to oxidative stress response and drug detoxification. In addition to its antioxidant properties, Nrf2 is involved in many other important physiological processes, including inflammation and metabolism. Nrf2 can bind the promoters of antioxidant genes and upregulates their expressions, which alleviate oxidation-induced inflammation. Nrf2 has been shown to upregulate heme oxygenase-1 expression, which promotes NF-κB activation and is closely related with inflammation. Nrf2, as a key factor in antioxidant response, is closely related to the expressions of pro-inflammatory factors, NF-κB pathway and cell metabolism. Bioactive peptides come from a wide range of sources and have many biological functions. Increasing evidence indicates that bioactive peptides have potential anti-inflammatory activities. This article summarized the sources, absorption and utilization of bioactive peptides and their role in alleviating inflammation via Nrf2 pathway. Bioactive peptides can also regulate gut microbiota and alter metabolites, which regulates the Nrf2 pathway through novel pathway and supplement the anti-inflammatory mechanisms of bioactive peptides. This review provides a reference for further study on the anti-inflammatory effect of bioactive peptides and the development and utilization of functional foods.

Production and characterization of anti-hypertensive and anti-diabetic peptides from fermented sheep milk with anti-inflammatory activity: in vitro and molecular docking studies.

BACKGROUND: The present study aimed to evaluate the anti-hypertensive and anti-diabetic activities from biologically active peptides produced by fermented sheep milk with Lacticaseibacillus paracasei M11 (MG027695), as well as to purify and characterize the angiotensin-converting enzyme (ACE) inhibitory and anti-diabetic peptides produced from fermented sheep milk. RESULTS: After 48 h of fermentation at 37 °C, sheep milk demonstrated significant changes in anti-diabetic effects and ACE-I effects, with inhibition percentages observed for ACE inhibition (76.32%), α-amylase (70.13%), α-glucosidase (70.11%) and lipase inhibition (68.22%). The highest level of peptides (9.77 mg mL-1) was produced by optimizing the growth conditions, which included an inoculation rate of 2.5% and a 48 h of incubation period. The comparison of molecular weight distributions among protein fractions was conducted through sodium dodecyl-sulfate polyacrylamide gel electrophoresis analysis, whereas spots were separated using 2D gel electrophoresis according to both the molecular weight and pH. Peptide characterization with ultra-filtration membranes at 3 and 10 kDa allowed the study to assess molecular weight-based separation. Nitric oxide generated by lipopolysaccharide and the secretion of pro-inflammatory cytokines in RAW 264.7 immune cells were both inhibited by sheep milk fermented with M11. Fourier-transform infrared spectroscopy was employed to assess changes in functional groups after fermentation, providing insights into the structural changes occurring during fermentation. CONCLUSION: The present study demonstrates that fermentation with L. paracasei (M11) led to significant changes in fermented sheep milk, enhancing its bioactive properties, notably in terms of ACE inhibition and anti-diabetic activities, and the generation of peptides with bioactive properties has potential health benefits. © 2024 Society of Chemical Industry.

Assessment of in vitro digestibility and post-digestion peptide release of mare milk in relation to different management systems and lactation stages.

Mare milk has a unique protein composition that makes it a preferred option for adult and infant nutrition. Several functional properties have been attributed to this milk but with little evidence yet. In fact, knowledge on mare milk composition is still limited. In particular, studies addressing the performance of mare milk proteins during human gastrointestinal digestion are scarce, which limits the understanding of mare milk nutritional quality and functionality. For this reason, the present study describes the digestibility of mare milk proteins and the release of peptides as affected by management and lactation stage, factors known to affect milk composition. Mare milk samples from 3 different farms, and collected during 6 mo of lactation (n = 54), were subjected to a static in vitro gastrointestinal model to measure peptide release and protein digestibility. In the present study, a detailed description of protein and individual amino acid behavior during the digestion process was given. For the first time, digestion of the 2 equine ß-lactoglobulin isoforms (I and II) was described individually. In addition, it was found that lactation stage and management system can significantly affect protein digestibility and peptide release during gastrointestinal digestion of mare milk. Presumably, differences in the composition of mare milk influence the protein structure and enzyme accessibility, which might have an impact on digestion behavior. Despite no specific bioactive peptides were identified, several precursors of previously described bioactive peptides were found. These findings could support the idea of mare milk as a food with added value.

Pulse Proteins and Their Hydrolysates: A Comprehensive Review of Their Beneficial Effects on Metabolic Syndrome and the Gut Microbiome.

Pulses, as an important part of the human diet, can act as a source of high-quality plant proteins. Pulse proteins and their hydrolysates have shown promising results in alleviating metabolic syndrome and modulating the gut microbiome. Their bioactivities have become a focus of research, with many new findings added in recent studies. This paper comprehensively reviews the anti-hypertension, anti-hyperglycemia, anti-dyslipidemia and anti-obesity bioactivities of pulse proteins and their hydrolysates in recent in vitro and in vivo studies, which show great potential for the prevention and treatment of metabolic syndrome. In addition, pulse proteins and their hydrolysates can regulate the gut microbiome, which in turn can have a positive impact on the treatment of metabolic syndrome. Furthermore, the beneficial effects of some pulse proteins and their hydrolysates on metabolic syndrome have been supported by clinical studies. This review might provide a reference for the application of pulse proteins and their hydrolysates in functional foods or nutritional supplements for people with metabolic syndrome.

Protective effects of the bioactive peptide from maggots against skin flap ischemia‒reperfusion injury in rats.

Ischemia‒reperfusion (I/R) injury is a frequently observed complication after flap surgery, and it affects skin flap survival and patient prognosis. Currently, there are no proven safe and effective treatment options to treat skin flap I/R injury. Herein, the potential efficacies of the bioactive peptide from maggots (BPM), as well as its underlying mechanisms, were explored in a rat model of skin flap I/R injury and LPS- or H2O2-elicited RAW 264.7 cells. We demonstrated that BPM significantly ameliorated the area of flap survival, and histological changes in skin tissue in vivo. Furthermore, BPM could markedly restore or enhance Nrf2 and HO-1 levels, and suppress the expression of pro-inflammatory cytokines, including TLR4, p-IκB, NFκB p65, p-p65, IL-6, and TNF-α in I/R-injured skin flaps. In addition, BPM treatment exhibited excellent biocompatibility with an adequate safety profile, while it exhibited superior ROS-scavenging ability and the upregulation of antioxidant enzymes in vitro. Mechanistically, the above benefits related to BPM involved the activation of Nrf2/HO-1 and suppression of TLR4/NF-κB pathway. Taken together, this study may provide a scientific basis for the potential therapeutic effect of BPM in the prevention of skin flap I/R injury and other related diseases.

Analytical Methods and Effects of Bioactive Peptides Derived from Animal Products: A Mini-Review.

Peptides with bioactive effects are being researched for various purposes. However, there is a lack of overall research on pork-derived peptides. In this study, we reviewed the process of obtaining bioactive peptides, available analytical methods, and the study of bioactive peptides derived from pork. Pepsin and trypsin, two representative protein digestive enzymes in the body, are hydrolyzed by other cofactors to produce peptides. Bicinchoninic acid assay, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, chromatography, and in vitro digestion simulation systems are utilized to analyze bioactive peptides for protein digestibility and molecular weight distribution. Pork-derived peptides mainly exhibit antioxidant and antihypertensive activities. The antioxidant activity of bioactive peptides increases the accessibility of amino acid residues by disrupting the three-dimensional structure of proteins, affecting free radical scavenging, reactive oxygen species inactivation, and metal ion chelating. In addition, the antihypertensive activity decreases angiotensin II production by inhibiting angiotensin converting enzyme and suppresses blood pressure by blocking the AT1 receptor. Pork-derived bioactive peptides, primarily obtained using papain and pepsin, exhibit significant antioxidant and antihypertensive activities, with most having low molecular weights below 1 kDa. This study may aid in the future development of bioactive peptides and serve as a valuable reference for pork-derived peptides.