Inhibition of TNBS-induced intestinal inflammation in crucian carp (Carassius carassius) by oral administration of bioactive Bioactive food derived peptides

Intestinal enteritis is a main issue in crucian carp production which results in massive economic loss. Traditional antibiotics used for disease prevention of crucian carp (Carassius carassius) have been banned, thus an alternative approach needs to be identified. In this study, the bioactive peptide was evaluated as a diet supplement for preventing intestinal inflammation in crucian carp. Intestinal inflammation was induced by intrarectal administration of a 2,4,6-trinitrobenzene sulfonic acid (TNBS) solution. The fish samples were fed with different diets for 14 days. The disease activity index (DAI), which included, fish swimming, food intake, anal inflammation, body surface, and ascites was determined daily. Intestine segments were stained with haematoxylin and eosin (H.E.) for histopathological analysis. The expression of cytokines, including interleukin-1β (IL-1β), interleukin-8 (IL-8), tumor necrosis factor α (TNF-α), and myeloperoxidase (MPO) in crucian carp were determined. In TNBS-induced groups, the DAI scores were dramatically increased compared to the control group. The histopathological analysis showed that the damage of the fish intestine after the injection of TNBS. The relative expression levels of pro-inflammation cytokines (TNF-α, IL-1β, IL-8, MPO) were significantly increased compared to the control group on day 1. In the TNBS-induced group feed with a diet supplemented with bioactive peptide, the symptoms of intestinal inflammation were relieved on day 3 and the mRNA expression levels of pro-inflammation cytokines (TNF-α, IL-1β, IL-8, MPO) were reduced compared to day 1. On day 7, the fish samples enrofloxacin group and bioactive peptide group were recovered from TNBS-induced intestinal inflammation. This study showed that the fish diet supplemented with bioactive peptide could help to prevent and recover from intestinal inflammation. Thus, the bioactive peptide can be used as a replacement for antibiotics to prevent disease in aquaculture production.

Antioxidant and protective effects of a peptide (VTAL) derived from simulated gastrointestinal digestion of protein hydrolysates of Magallana gigas against acetaminophen-induced HepG2 cells

Oxidative stress is an automatic mechanism responsible for the commencement and continuance of liver injury. In this study, an antioxidative peptide Val-Thr-Ala-Leu (VTAL) was purified from simulated gastrointestinal digestion of protein hydrolysates of the triploid oyster Magallana gigas. Significant antioxidant activity was identified, as well as a protective effect against acetaminophen (APAP)-induced human liver cancer (HepG2) cells. The results suggested that the antioxidant activity improved in a dose-dependent manner. The highest cell viability (88.105 ± 3.62%) was observed in 15 mM APAP-induced cells when treated with 25 μg/mL M. gigas peptide [M.g (pep)]. The peptide sequences include hydrophobic amino acids, which could be responsible for its chemoprotective and antioxidant activities. Treatment with M.g (pep) significantly promoted the proliferation of HepG2 cells, thus protecting them against APAP and imbuing them with significant antioxidant capacity. M.g (pep) could be beneficial for treating drug-induced oxidative stress and liver damage. Additionally, M.g (pep) could serve as an alternative to synthetic antioxidant drugs.

OL-FS13 alleviates experimental cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion (I/R) is the main cause of neurological injury after stroke. However, existing treatments for I/R injury are relatively poor, and relevant drugs need to be further explored. Amphibians have received increasing attention as a resource bank of bioactive peptides. However, reports on neuroprotective peptides from amphibians remain extremely rare. Here, we identified a new neuroprotective peptide (OL-FS13, amino acid sequence: FSLLLTWWRRRVC) from the odorous frog species Odorrana livida using a constructed cDNA library. OL-FS13 significantly improving infarct volume, behavioral and histological abnormalities in rats, and also showed neuroprotective activities in PC12 cell (by oxygen glucose deprivation/reoxygenation, OGD/R). Mechanistically, OL-FS13 increased the level of antioxidative enzymes to resist oxidative stress and alleviated endoplasmic reticulum (ER) stress induced by I/R and OGD/R. The use of ML385 (Nrf2 inhibitor) indicated that OL-FS13 relieved nerve damage caused by oxidative and ER stress by increasing the nuclear displacement of Nrf2. Collectively, this research provides a novel drug candidate for the clinical cerebral I/R curation.

Bioactive peptides of whey: obtaining, activity, mechanism of action, and further applications

Bioactive peptides derived from diverse food proteins have been part of diverse investigations. Whey is a rich source of proteins and components related to biological activity. It is known that proteins have effects that promote health benefits. Peptides derived from whey proteins are currently widely studied. These bioactive peptides are amino acid sequences that are encrypted within the first structure of proteins, which required hydrolysis for their release. The hydrolysis could be through in vitro or in vivo enzymatic digestion and using microorganisms in fermented systems. The biological activities associated with bio-peptides include immunomodulatory properties, antibacterial, antihypertensive, antioxidant and opioid, etc. These functions are related to general conditions of health or reduced risk of certain chronic illnesses. To determine the suitability of these peptides/ingredients for applications in food technology, clinical studies are required to evaluate their bioavailability, health claims, and safety of them. This review aimed to describe the biological importance of whey proteins according to the incidence in human health, their role as bioactive peptides source, describing methods, and obtaining technics. In addition, the paper exposes biochemical mechanisms during the activity exerted by biopeptides of whey, and their application trends.

PDGF-BB-derived supramolecular hydrogel for promoting skin wound healing

Chronic wounds represent a major challenge to the present healthcare system. In recent decades, many topical therapies have been investigated for the treatment of chronic wounds, including different types of wound dressings, antimicrobial agents, and cell therapy. Platelet-derived growth factor (PDGF) plays an important role in wound healing and has been approved for treatment of wounds related to diabetes mellitus. However, the high cost and short retention time of PDGF protein have limited its wide application. To overcome this challenge, we designed a PDGF-mimicking peptide by connecting PDGF epitope VRKIEIVRKK and self-assembling motif derived from β-amyloid peptide. The resultant peptide can self-assemble into a fibril-rich network and leads to supramolecular hydrogelation with good stability. The hydrophilic epitope can be exposed on the surface of nanofibrils, which might contribute to the binding and activation of PDGF receptors. The forming hydrogel is able to induce the growth and migration of vascular endothelial cells and promote the formation of vascular branches. In the full-thickness skin wounds of healthy mice, after the application of the hydrogel, the density of neovascularization marked by CD31 was greater than that in the control group on Day 3. Larger collagen deposition and a thicker epidermis were observed on Day 12. These results demonstrate that the hydrogel can stimulate collagen deposition and angiogenesis, enhance skin regeneration, and show an excellent therapeutic effect. Taken together, this work not only provides new insight into the design of bioactive peptides but also offers a promising biomaterial for wound healing.

Identification of a novel peptide that activates alcohol dehydrogenase from crucian carp swim bladder and how it protects against acute alcohol-induced liver injury in mice

Alcoholism is a severe threat to public health, and there are no adequate treatments for alcoholic liver disease. The aim of this study was to identify bioactive peptides derived from natural proteins that prevent acute alcohol-induced liver injury. We identified a peptide with the sequence Gly-Leu-hydroxyproline-Gly-Glu-Arg (GLpGER) from the hydrolysate of crucian carp swim bladder using size-exclusion chromatography and reversed-phase chromatography. The in vitro EC₅₀ value of GLpGER to activate alcohol dehydrogenase (ADH) was 137.9 ± 9 µM. Molecular docking experiments indicated that the mechanism by which GLpGER activates ADH may be related to the formation of stable complexes with ADH active pockets through hydrogen bonding, and electrostatic and hydrophobic interactions. Oral administration of GLpGER one hour before acute alcohol ingestion significantly increased alcohol metabolism, manifesting as reduced incidence of the loss of righting reflex, increased alcohol tolerance time, shortened sobering time, and decreased blood alcohol concentration level. GLpGER restored liver ADH activity, maintained the typical morphology of hepatocytes, and reduced serum levels of alanine aminotransferase and aspartate aminotransferase. These findings suggest that GLpGER might reduce acute alcohol-induced liver injury and may have the potential to be developed as an anti-inebriation ingredient.

Water distribution and moisture-absorption in egg-white derived peptides: Effects on their physicochemical, conformational, thermostable, and self-assembled properties

Three egg-white derived peptides (DHTKE, MPDAHL, and FFGFN) were characterized with hydrophilia and water distributions. The effect of moisture exposure on their properties at 75% relative humidity for 30 h were further investigated. LF-NMR tests revealed that strong bound-water (relaxation time < 10 ms) accounted for more than 80% of total water in peptides after moisture-absorption. The absorbed water led to the pH of three peptides increase, antioxidant activities in vitro decrease, and diverse changes in their functional group vibrations, molecular hydrophobicity, and phase transformation properties. Compared to dried samples, the hydrated-DHTKE was pyrolyzed and hydrated-MPDAHL was oxidized over 160 °C, while the glass transition, melting, and crosslink temperatures of FFGFN all decreased after moisture-absorption. Moreover, the results indicated that moisture-absorption in FFGFN powder enhanced the surface-hydrophobicity of FFGFN-hydrogel and accelerated its self-organizations. This study provides a comprehensive understanding of moisture-absorption effects on peptides, with these changes potentially impacting storage recommendations and scientific interpretations.

Structure-function relationship of fermented skate skin gelatin-derived bioactive peptides: a peptidomics approach

In this study, we investigated the multi-functionality of bioactive peptides derived from fermented skate (Raja kenojei) skin gelatin hydrolysates. The extracted gelatin was hydrolyzed using a combination of food grade subtilisin and actinidin. The hydrolysates were then fractionated via ultrafiltration, and the fractions with the highest dipeptidyl peptidase-IV (DPP-IV) inhibitory, angiotensin-converting enzyme (ACE) inhibitory, and antibacterial proprieties were further purified via ion exchange, solid phase extraction, and reverse phase high performance liquid chromatography. Analysis of the obtained extract revealed a direct relationship between hydrolysis time, degree of hydrolysis, and biological activities. The peptides GRPGNRGE (P1) and AKDYEVDAT (P2), with a molecular weight of 841.42 and 1010.46 Da, respectively, were identified through tandem mass spectrometry. P1 had a lower ACE and DPP-IV inhibitory activity, with a half maximal inhibitory concentration [IC₅₀] of 0.74 and 0.69 mg.mL^-1, respectively, than P2 (0.52 and 0.58 mg.mL^-1, respectively). Antibacterial analysis showed similar results, with a minimum inhibitory concentration of 0.52 and 0.46 mg.mL^-1 against Staphylococcus aureus (highest activity) and 1.75 and 1.44 mg.mL^-1 against Klebsiella pneumonia (lowest activity) for P1 and P2, respectively. Overall, this study revealed two fish gelatin-derived multifunctional peptides, exhibiting ACE inhibitory, DPP-IV inhibitory, and antibacterial activities, as natural nutraceuticals.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-021-00998-6.

Biological, functional and nutritional properties of caseinomacropeptide from sweet whey

Bioactive peptides derived from bovine milk proteins have gained much attention due to their health promoting functions. All over the world, cheese industry generates high volumes of sweet whey that could be used as an alternative source of bioactive peptide in nutraceuticals and food industry. Caseinomacropeptide (CMP) is a bioactive peptide derived from κ-casein by the action of chymosin during cheese manufacturing. CMP consist of two forms which are glycosylated (gCMP) and non-glycosylated (aCMP). The predominant carbohydrate in gCMP is N-acetylneuraminic (sialic acid) which gives functional and biological properties to gCMP. Due to its unique composition and technological characteristics such as wide pH range solubility, emulsifying, gelling, and foaming ability, CMP has received special attention. Therefore, there is an increased interest in researches for isolation and concentration of CMP. However, the isolation and purification methods are not cost-effective. It would be easier to optimize the conditions for isolation, purification, and utilization of CMP in nutraceuticals and food industry through deeper understanding of the effective factors. In this review, the structure of CMP, biological activities, isolation, and purification methods, the factors affecting functional properties and application areas of CMP in food industry are discussed.

Appetite regulation by plant-derived bioactive peptides for promoting health

Appetite is closely regulated not only by gut hormonal and neuronal peptides but also by exogenous peptides derived from food proteins. Food proteins are now recognized to contain many thousands of bioactive compounds that provide additional health benefits beyond their nutritional effects. Bioactive peptides are beneficial to the life and/or to regulate physiological functions. Although animal protein products have been widely applied in the food industry, exploring the possibilities of developing functional foods based on plant protein-derived peptides is considered attractive for achieving sustainable development goals. In addition, peptides from plant proteins have the potential to treat numerous diseases or risk factors and may therefore facilitate a healthy life expectancy. In this review, we discuss the identified plant-based bioactive peptides and their appetite regulating effects. Plant-based bioactive peptides may provide new opportunities to discover novel approaches that can improve and prevent diseases in a sustainable environment.

Theoretical benefits of yogurt-derived bioactive peptides and probiotics in COVID-19 patients - A narrative review and hypotheses

The world is currently facing a frightening coronavirus disease-2019 (COVID-19) epidemic. Severity of COVID-19 presentation is highly variable among infected individuals with increasingly recognized risk factors. Although observational studies suggested lower COVID-19 severity in populations consuming fermented foods, no controlled study investigated the role of diet. Yogurt, a fermented dairy product, exhibits interesting properties related to the presence of bioactive peptides and probiotics that may play a beneficial role in COVID-19 presentation and outcome. Peptides contained in yogurt are responsible for angiotensin-converting enzyme-inhibitory, bradykinin potentiating, antiviral, anti-inflammatory, antithrombotic, and antioxidant effects. The types and activity of these peptides vary widely depending on their amino acid sequence, on the probiotics used in yogurt production and on intestinal digestion. Additionally, probiotics used in yogurt exhibit direct angiotensin-converting enzyme-inhibitory, antiviral and immune boosting activities. Since COVID-19 pathogenesis involves angiotensin II accumulation and bradykinin deficiency, yogurt bioactive peptides appear as potentially beneficial. Therefore, epidemiological investigations and randomized controlled clinical trials to evaluate the exact role of yogurt consumption on COVID-19 manifestations and outcome should be encouraged.

Identification and characterisation of a novel heptapeptide mackerel by-product hydrolysate, and its potential as a functional fertiliser component

Functional fertilisers for hydroponics are in great demand. Herein, we isolated peptides from mackerel by-products, a valuable source of bioactive peptides. The pellet-phase fraction obtained after cold-acetone extraction exhibited plant growth-promoting activity in wheat hydroponics, and the presumed peptides were determined to be ≤ 1 kDa based on molecular weight cut-off and tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Size exclusion chromatography and matrix-assisted laser desorption ionisation time of flight mass spectrometry analysis were employed for peptide purification and identification. Finally, two peptides were identified, both with linear structures, consisting of amino acid sequences TCGGQGR and KEAGAFIDR. At 1 mg/mL, the heptapeptide performed better than the nonapeptide in terms of wheat growth and health, but neither peptide exhibited antimicrobial activity. Only the heptapeptide displayed significant antioxidant activity, and this activity bioaccumulated in wheat leaves after 7 days of hydroponic growth. The heptapeptide did not match any known metabolites in PepBank, BIOPEP, UniProt or METLIN databases, and is therefore a novel peptide with potential as a functional fertiliser component.

Plasma Level of Elabela in Patients with Coronary Heart Disease and Its Correlation with the Disease Classification

This study aimed to evaluate the concentration of plasma elabela (ELA) in patients with coronary heart disease (CHD) and its correlation with the disease classification.We enrolled 238 patients diagnosed by coronary angiography as CHD and 86 controls. The CHD group was divided into three subgroups: stable angina (SA), unstable angina (UAP), and acute myocardial infarction (AMI). The plasma levels of ELA were measured in all participants and compared among different groups. The relationship between ELA and CHD classification was analyzed.ELA levels were markedly higher by 10.71% in patients with CHD than in controls (P < 0.05). The concentration of ELA in UAP and AMI subgroups were higher than in controls and SA subgroup. The former difference was significant (P < 0.05), but the latter was not. In addition, the ELA concentration was not correlated with SYNTAX score, left ventricular ejection fraction, and other biochemical variables.The newfound hormone, ELA, significantly increased in patients with UAP and AMI. There is a tendency that ELA levels might be correlated with CHD classification, but not with lesion severity. ELA may play a role in acute coronary syndrome.

Endothelin-1 enhances the regenerative capability of human bone marrow-derived mesenchymal stem cells in a sciatic nerve injury mouse model

We expanded the application of endothelin-1 (EDN1) by treating human mesenchymal stem cell (hMSC) organotypic spinal cord slice cultures with EDN1. EDN1-treated hMSCs significantly enhanced neuronal outgrowth. The underlying mechanism of this effect was evaluated via whole-genome methylation. EDN1 increased whole-genome demethylation and euchromatin. To observe demethylation downstream of EDN1, deaminases and glycosylases were screened, and APOBEC1 was found to cause global demethylation and OCT4 gene activation. The sequence of methyl-CpG-binding domain showed similar patterns between EDN1- and APOBEC1-induced demethylation. SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin subfamily A member 4 (SMARC A4) and SMARC subfamily D, member 2 (SMARC D2) were screened via methyl-CpG-binding domain sequencing as a modulator in response to EDN1. Chromatin immunoprecipitation of the H3K9me3, H3K27me3, and H3K4me4 binding sequences on the APOBEC1 promoter was analyzed following treatment with or without siSMARC A4 or siSMARC D2. The results suggested that SMARC A4 and SMARC D2 induced a transition from H3K9me3 to H3K4me3 in the APOBEC1 promoter region following EDN1 treatment. Correlations between EDN1 pathways and therapeutic efficacy in hBM-MSCs were determined in a sciatic nerve injury mouse model. Thus, EDN1 may be a useful novel-concept bioactive peptide and biomaterial component for improving hMSC regenerative capability.

A highly efficient method for extracting peptides from a single mouse hypothalamus

Living organisms contain a variety of endogenous peptides that function as significant regulators of many biological processes. Endogenous peptides are typically analyzed using liquid chromatography-mass spectrometry (LC-MS). However, due to the low efficiency of peptide extraction and low abundance of peptides in a single animal, LC-MS-based peptidomics studies have not facilitated an understanding of the individual differences and tissue specificity of peptide abundance. In this study, we developed a peptide extraction method followed by nano-flow LC-MS/MS analysis. This method enabled highly efficient and reproducible peptide extraction from sub-milligram quantities of hypothalamus dissected from a single animal. Diverse bioactive and authentic peptides were detected from a sample volume equivalent to 135 μg of hypothalamus. This method may be useful for elucidating individual differences and tissue specificity, as well as for facilitating the discovery of novel bioactive peptides and biomarkers and developing peptide therapeutics.

Characterising the efficacy and bioavailability of bioactive peptides identified for attenuating muscle atrophy within a Vicia faba-derived functional ingredient

Characterising key components within functional ingredients as well as assessing efficacy and bioavailability is an important step in validating nutritional interventions. Machine learning can assess large and complex data sets, such as proteomic data from plants sources, and so offers a prime opportunity to predict key bioactive components within a larger matrix. Using machine learning, we identified two potentially bioactive peptides within a Vicia faba derived hydrolysate, NPN_1, an ingredient which was previously identified for preventing muscle loss in a murine disuse model. We investigated the predicted efficacy of these peptides in vitro and observed that HLPSYSPSPQ and TIKIPAGT were capable of increasing protein synthesis and reducing TNF-α secretion, respectively. Following confirmation of efficacy, we assessed bioavailability and stability of these predicted peptides and found that as part of NPN_1, both HLPSYSPSPQ and TIKIPAGT survived upper gut digestion, were transported across the intestinal barrier and exhibited notable stability in human plasma. This work is a first step in utilising machine learning to untangle the complex nature of functional ingredients to predict active components, followed by subsequent assessment of their efficacy, bioavailability and human plasma stability in an effort to assist in the characterisation of nutritional interventions.

FermFooDb: A database of bioactive peptides derived from fermented foods

Globally fermented foods are in demands due to their functional and nutritional benefits. These foods are sources of probiotic organisms and bioactive peptides, various amino acids, enzymes etc. that provides numerous health benefits. FermFooDb (https://webs.iiitd.edu.in/raghava/fermfoodb/) is a manually curated database of bioactive peptides derived from wide range of foods that maintain comprehensive information about peptides and process of fermentation. This database comprises of 2205 entries with following major fields, peptide sequence, Mass and IC50, food source, functional activity, fermentation conditions, starter culture, testing conditions of sequences in vitro or in vivo, type of model and method of analysis. The bioactive peptides in our database have wide range of therapeutic potentials that includes antihypertensive, ACE-inhibitory, antioxidant, antimicrobial, immunomodulatory and cholesterol lowering peptides. These bioactive peptides were derived from different types of fermented foods that include milk, cheese, yogurt, wheat and rice. Numerous, web-based tools have been integrated to retrieve data, peptide mapping of proteins, similarity search and multiple-sequence alignment. This database will be useful for the food industry and researchers to explore full therapeutic potential of fermented foods from specific cultures.

Bioactive dipeptide from potato protein hydrolysate combined with swimming exercise prevents high fat diet induced hepatocyte apoptosis by activating PI3K/Akt in SAMP8 mouse

Obesity in aged population have surges the occurrence of various metabolic disorders including Nonalcoholic fatty liver disease (NAFLD). Apoptosis in the liver is one of the causative factors for NAFLD-induced liver damage. Plants derived bioactive peptides have been shown as an alternative treatment approach for the treating NAFLD due to its less toxicity. Moderate exercise has been reported to improve cellular physiological function prevent age associated metabolic disorders. In the present study, we evaluate the effects of bioactive dipeptide (IF) derived from alcalase potato-protein hydrolysates and swimming exercise in preventing High Fat Diet (HFD)-induced liver damage in senescence accelerated mouse-prone 8 (SAMP8) mice model. Mouse were fed with HFD for 6 weeks followed by oral IF administration or swimming exercise and both for 8 weeks. HFD induces significant structural changes in liver of HFD fed SAMP8 mouse. Both IF administration and exercise prevent the structural abnormalities induced by HFD, however, combined IF treatment and exercise offer better protection. Combined IF treatment and exercise activate PI3K/Akt cell survival protein and effectively inhibit Fas-FADD-induced apoptosis in HFD fed aged mouse. Oral supplementation of bioactive peptide IF combined with moderate swimming exercise effectively alleviate HFD-induced hepatic injury in aged mice.

Functional properties of ovotransferrin from chicken egg white and its derived peptides: a review

With emerging trends in the food and pharmaceutical industries, potential applications of egg-derived bioactive compounds were recognized. Ovotransferrin is a major egg white functional protein responsible for multiple bioactivities. The objectives of this review are to provide scientific evidence of the functional properties of chicken ovotransferrin and its derived peptides and to identify future research approaches and applications. Various easy, economical, and non-toxic methods have been reported to produce ovotransferrin with high yield and purity, and chemical and enzymatic approaches have been employed to release bioactive peptides. The native ovotransferrin is known to have antimicrobial, antioxidant, anticancer, and immunomodulatory activities. The peptides produced from ovotransferrin also are reported to have antioxidant, antimicrobial, antihypertensive, and anticancer properties. However, little or no application of these compounds in the food and pharmaceutical areas is available yet. Therefore, the practical application of OTF in nutraceutical and pharmaceutical areas are among the emerging areas of research.

Changes in the stability and antioxidant activities of different molecular weight bioactive peptide extracts obtained from beef during in vitro human digestion by gut microbiota

This study was conducted to determine changes in the stability and antioxidant activity of extracts of bioactive peptides with different molecular weights (<3 and <10 kDa) obtained from beef myofibrillar protein using commercial enzymes (alkaline-AK and papain) during in vitro human digestion by gut microbiota. After the digestion in the large intestine, the stability of the bioactive peptide extracts decreased regardless of their molecular weight. However, the peptides obtained following alkaline-AK treatment were less stable than those obtained following papain digestion. The radical scavenging activities of the peptide extracts also decreased during in vitro human digestion, regardless of the molecular weights of the peptides and the commercial enzymes used. These results indicate that the stability and antioxidative activity of the bioactive peptides were affected by the digestion process by the gut microbiota. This study provides data supporting the changes in the stability and bioavailability of functional materials within the human body.

Novel bioactive peptides of Achillea eriophora show anticancer and antioxidant activities

Despite the limitations of current methods in cancer treatment, the use of bioactive peptides can be as an alternative to treat today. Therefore, isolation and relative purification of bioactive peptides was carried out form Achillea eriophora using a Sep-Pak C18 SPE cartridge and Amicon® Ultra Centrifugal Filters. The presence of desired peptides was checked using RP-HPLC and confirmed using LC-MS. The results of anticancer assay showed that the peptide mixture inhibits the growth of MCF-7 cancerous cell line with the values of IC₅₀, GI₅₀, and LC₅₀ equal to 18.73 ± 0.22, 7.52 ± 0.15, and 56.73 ± 0.18 µg/mL, respectively. It also showed DPPH radical scavenging activity and cupric-ion reducing power with the IC₅₀ value of 5.095 ± 0.23 and 63.3 ± 0.44 µg/mL, respectively. Although flavonoids were present in the sample along with the peptides, their amount was trivial (18.097 ± 1.36 μg/mL). Nevertheless, the results of the LC-MS showed mass-to-charge ratios of 301.17, 261.22, and 243.25, which was a dipeptide or tripeptide in compression to enzyme-digested BSA as a standard. In addition, SEM analysis of the purified peptide mixture showed that it kills the MCF-7 cancerous cell line by creating pores in the membrane. Therefore, it might be valuable to these peptides sequenced and be studied for physicochemical properties. Animal and clinical studies could help its application in drug development.

Effects of periodical application of bioactive peptides derived from cottonseed on performance, immunity, total antioxidant activity of serum and intestinal development of broilers

This experiment aimed to examine the effect of periodical application of bioactive peptides derived from cottonseed (BPC) in comparison with using sub-therapeutic doses of lincomycin and the excessive inclusion of vitamin E on performance, immunity, total antioxidant capacity of serum and intestinal morphology of broiler chickens. A total of 240 one-d-old male broiler chicks with similar initial weight (Ross strain) were randomly assigned to 6 groups (8 chicks/pen): non-treated group (basal diet), basal diet supplemented with 2 mg/kg lincomycin, basal diet supplemented with 50 IU vitamin E, basal diet supplemented with 6 g BPC/kg in starter period, basal diet supplemented with 6 g BPC/kg in starter and grower periods and basal diet supplemented with 6 g BPC/kg throughout the whole experiment. The highest final body weight was obtained in the group supplemented with BPC in starter and grower periods. In the finisher phase, broilers fed the diet containing BPC in the starter period and in the whole trial had significantly (P < 0.05) better feed conversion ratios (FCR). Jejunal villus height was significantly elevated in broilers supplemented with antibiotic (P < 0.001), furthermore it tended to be greater in broilers fed BPC in the starter period. The jejunal villus height-to-crypt depth ratio was significantly (P < 0.01) higher in broilers fed the diet containing antibiotic in comparison to other groups. Humoral immune response against Newcastle disease vaccine tended to be elevated in broilers fed the diet containing BPC in the whole trial (P > 0.05). Broilers supplemented with BPC in starter and grower, and in the whole trial had significantly (P < 0.05) higher antibody titers against sheep red blood cells (SRBC). The highest total antioxidant capacity was obtained in broilers supplemented with the excessive level of vitamin E, furthermore it tended to improve in broilers fed the diet containing BPC in the whole trial. In summary, the results of the study indicated that addition of BPC in broiler diets in the whole trial could improve FCR, immune responses and total antioxidant activity of serum, and BPC could be used in broiler diets as an alternative to in-feed antibiotics.

Conformational change following conversion of inactive rhinophrynin-33 to bioactive rhinophrynin-27 in the skin of the frog Rhinophrynus dorsalis

Skin secretions of the Mexican burrowing toad Rhinophrynus dorsalis (Rhinophrynidae) contain the proline-arginine-rich peptide, rhinophrynin-27 (RP-27; ELRLPEIARPVPEVLPARLPLPALPRN) with insulinotropic and immunomodulatory properties, together with a higher concentration of the biologically inactive form, rhinophrynin-33 (RP-33) that constitutes RP-27 extended from its C-terminus by the hexapeptide KMAKNQ. Determination of the conformation of RP-33 by NMR demonstrates that in both water and in a solvent that promotes protein folding (50% trifluoroethanol-water), the majority of the proline residues are found in a polyproline type II helical region. The peptide adopts a horseshoe (U-shaped) conformation with pronounced bends in the molecule of around 100°-120° at Glu¹³ and Arg¹⁸. The hexapeptide extension adopts a α-helical conformation. When the hexapeptide is excised to generate RP-27, the molecule adopts an L-shaped conformation with a single bend at Glu¹³. A search of protein sequence databases indicated the P-X-P-XXX-P-XXX-P-X-P motif found in RP-27 and RP-33 occurs in a number of proteins although its functional implications are unclear. The data suggest that RP-33 represents a biosynthetic precursor of RP-27 that is activated by a protease cleaving at a single lysine residue of the type previously identified in Xenopus laevis skin secretions.

Identification of an antiviral component from the venom of the scorpion Liocheles australasiae using transcriptomic and mass spectrometric analyses

Scorpion venom contains a variety of biologically active peptides. Among them, neurotoxins are major components in the venom, but it also contains peptides that show antimicrobial activity. Previously, we identified three insecticidal peptides from the venom of the Liocheles australasiae scorpion, but activities and structures of other venom components remained unknown. In this study, we performed a transcriptome analysis of the venom gland of the scorpion L. australasiae to gain a comprehensive understanding of its venom components. The result shows that potassium channel toxin-like peptides were the most diverse, whereas only a limited number of sodium channel toxin-like peptides were observed. In addition to these neurotoxin-like peptides, many non-disulfide-bridged peptides were identified, suggesting that these components have some critical roles in the L. australasiae venom. In this study, we also isolated a component with antiviral activity against hepatitis C virus using a bioassay-guided fractionation approach. By integrating mass spectrometric and transcriptomic data, we successfully identified LaPLA₂-1 as an anti-HCV component. LaPLA₂-1 is a phospholipase A₂ having a heterodimeric structure that is N-glycosylated at the N-terminal region. Since the antiviral activity of LaPLA₂-1 was inhibited by a PLA₂ inhibitor, the enzymatic activity of LaPLA₂-1 is likely to be involved in its antiviral activity.

Fabrication and characterization of double (W1/O/W2) emulsions loaded with bioactive peptide/polysaccharide complexes in the internal water (W1) phase for controllable release of bioactive peptide

The objective of this study was to develop food-grade double emulsions containing bioactive peptide (BP)/polysaccharide (P) complexes and to investigate their thermal stability (e.g., BP release) at different temperatures. The BP/P complexes were formed via electrostatic interactions, and successfully encapsulated into the internal water phase of double emulsions with different oil phases. All emulsions clearly showed temperature dependence during storage. BP/P complex-loaded double emulsions showed higher thermal stability and lower release of encapsulated BP (45 °C: < 1%, 65 °C: < 30%) over time, which effectively prevented BP release within the emulsion system. For the effect of the oil phase, the BP released from double emulsions was in the order of MCT > coconut > canola oil. Thus, we concluded that BP release can be controlled in double emulsions by differently charged polysaccharides and oil types and that BP/P-loaded double emulsions can be utilized as functional ingredients for developing heat-sensitive food products.