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Tomato ( Solanum lycopersicum ) is a widely consumed fruit all around the world. The industrial exploitation of tomato generates a lot of waste. Most of the utilization of tomato seeds waste is focused on animal feeding, as well as a food ingredient aimed to increase the protein content, and raw material for some organic bioactive component extraction. The aim of this work was to evaluate the techno-functional properties of tomato seed meal (TSM) and its nutraceutical properties after applying defatting processing (TSMD), and to evaluate the nutraceutical properties after a fermentation processing (TSMDF) by Lactobacillus sp. The results showed that, at alkaline conditions (pH 8-9), the techno-functional properties for TSM and TSMD improved. In comparison with TSM, TSMD showed higher water holding capacity (WHC ≈32%), higher oil holding capacity (OHC ≈13%), higher protein solubility (49-58%), more than 10 times foaming activity (FA), more than 50 times foam stability (Fst), as well as an improved emulsifying activity (EA) and emulsion stability (Est) wich were better at pH 9. Regarding the nutraceutical properties, after 48 h of fermentation (TSMDF), the antioxidant activity was doubled and a significant increase in the iron chelating activity was also observed. During the same fermentation time, the highest angiotensin-converting enzyme inhibition (ACEI) was achieved (IC50 73.6 μg/mL), more than 10 times higher than TSMD, which leads to suggest that this fermented medium may be a powerful antihypertensive. Therefore, the strategy proposed in this study could be an option for the exploitation of tomato wastes.

Over the years, coronaviruses (CoV) have posed a severe public health threat, causing an increase in mortality and morbidity rates throughout the world. The recent outbreak of a novel coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the current Coronavirus Disease 2019 (COVID-19) pandemic that affected more than 215 countries with over 23 million cases and 800,000 deaths as of today. The situation is critical, especially with the absence of specific medicines or vaccines; hence, efforts toward the development of anti-COVID-19 medicines are being intensively undertaken. One of the potential therapeutic targets of anti-COVID-19 drugs is the angiotensin-converting enzyme 2 (ACE2). ACE2 was identified as a key functional receptor for CoV associated with COVID-19. ACE2, which is located on the surface of the host cells, binds effectively to the spike protein of CoV, thus enabling the virus to infect the epithelial cells of the host. Previous studies showed that certain flavonoids exhibit angiotensin-converting enzyme inhibition activity, which plays a crucial role in the regulation of arterial blood pressure. Thus, it is being postulated that these flavonoids might also interact with ACE2. This postulation might be of interest because these compounds also show antiviral activity in vitro. This article summarizes the natural flavonoids with potential efficacy against COVID-19 through ACE2 receptor inhibition.

Hypertension (HT) is considered to be a potential risk factor for cardiovascular diseases and has been directly related to pathologies such as obesity and dyslipidemias. Angiotensin-converting enzyme inhibitors (ACEIs) blocked the renin-angiotensin-aldosterone cascade diminishing the production of angiotensin II and the level of bradykinin, produced by the kallikrein-kinin system. Although ACEIs are effective therapeutics in regulating HT, they present several side-effects that can be due to their mechanism of action (as hypotension, cough, dizziness, light-headedness or hyperkalemia) to specific drug molecular structure (skin rash, neutropenia and tasting disorders) or due to associated pathologies in the patients (it has been considered a possible nephrotoxic effect when ACEIs are administered in combination with angiotensin receptor blockers, in patients that present comorbidities as diabetes, acute kidney injury or chronic kidney disease). Therefore, it is necessary the searching for new products with ACEI activity that do not produce side effects. Interestingly, species of the plant genus Salvia have been found to possess hypotensive effects. In the present study, we analyzed the effects of the ethanolic extract of Salvia hispanica L. seeds (EESH) on the expression of genes involved in pathways regulating HT. Administration of EESH to hypertensive rats inhibited the angiotensin-converting enzyme (ACE) activity along with a decrease in Ace and elevation of Agtr1a and Nos3 gene expression, as compared to that in healthy rats. Moreover, these results were similar to those observed with captopril, an antihypertensive drug used as a control. No significant change in the expression of Bdkrb2 gene was observed in the different groups of rats. To conclude, our results demonstrate that EESH regulates blood pressure (BP) in hypertensive rats through transcriptionally regulating the expression of genes that participate in different pathways involving ACE.

Summary: iBioProVis is an interactive tool for visual analysis of the compound bioactivity space in the context of target proteins, drugs and drug candidate compounds. iBioProVis tool takes target protein identifiers and, optionally, compound SMILES as input, and uses the state-of-the-art non-linear dimensionality reduction method t-Distributed Stochastic Neighbor Embedding (t-SNE) to plot the distribution of compounds embedded in a 2D map, based on the similarity of structural properties of compounds and in the context of compounds' cognate targets. Similar compounds, which are embedded to proximate points on the 2D map, may bind the same or similar target proteins. Thus, iBioProVis can be used to easily observe the structural distribution of one or two target proteins' known ligands on the 2D compound space, and to infer new binders to the same protein, or to infer new potential target(s) for a compound of interest, based on this distribution. Principal component analysis (PCA) projection of the input compounds is also provided, Hence the user can interactively observe the same compound or a group of selected compounds which is projected by both PCA and embedded by t-SNE. iBioProVis also provides detailed information about drugs and drug candidate compounds through cross-references to widely used and well-known databases, in the form of linked table views. Two use-case studies were demonstrated, one being on angiotensin-converting enzyme 2 (ACE2) protein which is Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Spike protein receptor. ACE2 binding compounds and seven antiviral drugs were closely embedded in which two of them have been under clinical trial for Coronavirus disease 19 (COVID-19)., Availability and Implementation: iBioProVis and its carefully filtered dataset are available at https://ibpv.kansil.org/ for public use., Contact: vatalay@metu.edu.tr., Supplementary Information: Supplementary data are available at Bioinformatics online., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Umami peptides can help reduce the salt content in foods while still maintaining a savory taste. Few studies have reported the bioactivity of umami peptides after consumption. We studied the bioactivities of 12 umami peptides after gastrointestinal digestion. Three umami peptides exhibited angiotensin I-converting enzyme (ACE) inhibitory and antioxidant activity after digestion. Six novel peptides were identified from digestion solutions of the peptides by HPLC-MS/MS. Among them, CC, CCNK, and HCHT had both ACE inhibitory activity (IC 50 values were 9.81, 9.00, and 114.99 μM, respectively) and antioxidant activity (strong 1,1-Diphenyl-2-pycryl-hydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging activities). AHSVRF had strong ACE inhibitory activity. These peptides increased the nitric oxide concentration and decreased the content of endothelin-1 in a medium of human umbilical vein endothelial cells in a dose-dependent manner. Experiments with damaged HepG2 cells showed that peptides CC, CCNK, and HCHT had antioxidant activity through their cytoprotective effects and by reducing the reactive oxygen species content. The results indicated that umami peptides may provide many health benefits after consumption.

Mushroom bioactive peptides (MBAPs) refer to bioactive peptides extracted directly or indirectly from mushrooms or their mycelia. Owing to the presence of a large quantity of high-quality proteins, many mushrooms are promising sources of bioactive peptides. The beneficial effects, including antihypertensive, antioxidant, and antimicrobial activities, of MBAPs are being increasingly recognized with regards to health promotion and disease prevention. However, this field is relatively undeveloped and relevant reviews are scarce. Hence, the aim of this review was to present the current research status of MBAPs, focusing on their preparation and biological functions. An insight regarding the direction of future research has been also discussed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Hypertension is an important cardiovascular disease, which need long-term medication. Thus, oral drug delivery system is a preferred route for hypertension patients due to the convenience and compliance. Val-Leu-Pro-Val-Pro (VLPVP, VP5) is an angiotensin converting enzyme inhibitory peptide with antihypertensive effects. However, the oral peptide delivery is faced with obstacles, such as gastric acid, enzyme degradation and intestine barriers. Herein, we developed a controlled release system consisting of a PLGA core encapsulated with VP5 and a folate-decorated lipid shell (FA-VP5-LNPs) for the oral delivery of antihypertensive peptide. The results found that FA-VP5-LNPs exhibited high stability and possessed a controlled release behavior. Besides, FA-VP5-LNPs improved the cellular uptake both in Caco-2 and HT29 cells and enhanced in situ intestinal absorption in SD rats. The in vivo bioavailability study showed a superior oral absorption of FA-VP5-LNPs, and the AUC 0-72 h of FA-VP5-LNPs was 30.71-fold higher than that of free VP5. The pharmacodynamics study exhibited that FA-VP5-LNPs maintained strong antihypertensive effect for six days compared with free VP5, which may reduce the frequency of administration and improve patient compliance. In addition, the nano-formulations showed no toxicity to cells and tissues. These promising results suggested that FA-VP5-LNPs could overcome the intestinal barrier and provide a potential strategy for enhancing peptide delivery and improve the antihypertensive effects., Competing Interests: Declaration of Competing Interest There are no conflicts to declare., (Copyright © 2020. Published by Elsevier Ltd.)

Addition of probiotics to yogurt with desired health benefits is gaining increasing attention. To further understand the effect of probiotic Lactobacillus plantarum on the quality and function of fermented milk, probiotic fermented milk (PFM) made with probiotic L. plantarum K25 and yogurt starter ( L. delbrueckii ssp. bulgaricus and Streptococcus thermophilus ) was compared with the control fermented milk (FM) made with only the yogurt starter. The probiotic strain was shown to survive well with a viable count of 7.1 ± 0.1 log CFU/g in the PFM sample after 21 days of storage at 4°C. The strain was shown to promote formation of volatiles such as acetoin and 2,3-butanediol with milk fragrance, and it did not cause post-acidification during refrigerated storage. Metabolomics analysis by GC-MS datasets coupled with multivariate statistical analysis showed that addition of L. plantarum K25 increased formation of over 20 metabolites detected in fermented milk, among which γ-aminobutyric acid was the most prominent. Together with several other metabolites with relatively high levels in fermented milk such as glyceric acid, malic acid, succinic acid, glycine, alanine, ribose, and 1,3-dihydroxyacetone, they might play important roles in the probiotic function of L. plantarum K25. Further assay of the bioactivity of the PFM sample showed significant ( p < 0.05) increase of ACE inhibitory activity from 22.3% at day 1 to 49.3% at day 21 of the refrigerated storage. Therefore, probiotic L. plantarum K25 could be explored for potential application in functional dairy products.

The study analyzed the inhibitory effects (IC50) of crude and purified extracts from Maliniak, Cerise, Black Prince and Lima tomatoes on the formation of advanced glycation end products (AGEs), the activity of angiotensin-converting (ACE) and acetylcholinesterase (AChE) enzymes. Polyphenol composition (LC-MS) and antioxidant capacity (PCL, FRAP) were measured. The purified extracts of Black Prince tomatoes were the most potent inhibitors of AGEs in BSA-GLU (7.20mg/mL) and BSA-MGO (9.53mg/mL) models. The purified extracts of Cerise and Black Prince tomatoes had the highest ACE (0.50-0.44mg/mL) and AChE (7.93-5.83mg/mL) inhibitory activity. Cerise variety showed the highest polyphenol concentrations in crude (488.93μg/g DM) and purified (8394.99μg/g DM) extracts. The highest PCLACW and FRAP values were found for Cerise purified extracts (71.83 and 87.78μmol Trolox/g DM). Caffeic acid, caffeoyl-glucose, linocaffein, glucosyl-coumarate, vanillic acid, rutin and TPI values were significantly correlated with BSA-MGO, anti-ACE, anti-AChE and PCLACW parameters., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Inhibition of angiotensin I-converting enzyme (ACE) is one of the key factors to repress high blood pressure. Although many studies have been reported that seaweed protein hydrolysates showed the ACE inhibitory activity, the comprehensive understanding of the relationship was still unclear. In this study, we employed chloroplast genome for in silico analysis and compared it with in vitro experiments. We first extracted water-soluble proteins (WSP) from red alga Grateloupia asiatica, which contained mainly PE, PC, APC, and Rbc, and prepared WSP hydrolysate by thermolysin, resulting that the hydrolysate showed ACE inhibitory activity. Then, we determined the complete chloroplast genome of G. asiatica (187,518 bp: 206 protein-coding genes, 29 tRNA, and 3 rRNA) and clarified the amino acid sequences of main WSP, i.e., phycobiliproteins and Rubisco, to perform in silico analysis. Consequently, 190 potential ACE inhibitory peptides existed in the main WSP sequences, and 21 peptides were obtained by in silico thermolysin digestion. By comparing in vitro and in silico analyses, in vitro ACE inhibitory activity was correlated to the IC 50 value from in silico digestion. Therefore, in silico approach provides insight into the comprehensive understanding of the potential bioactive peptides from seaweed proteins.

Neprilysin (NEP) and angiotensin-converting enzyme (ACE) are two key zinc-dependent metallopeptidases in the natriuretic peptide and kinin systems and renin-angiotensin-aldosterone system, respectively. They play an important role in blood pressure regulation and reducing the risk of heart failure. Vasopeptidase inhibitors omapatrilat and sampatrilat possess dual activity against these enzymes by blocking the ACE-dependent conversion of angiotensin I to the potent vasoconstrictor angiotensin II while simultaneously halting the NEP-dependent degradation of vasodilator atrial natriuretic peptide. Here, we report crystal structures of omapatrilat, sampatrilat, and sampatrilat-ASP (a sampatrilat analogue) in complex with NEP at 1.75, 2.65, and 2.6 Å, respectively. A detailed analysis of these structures and the corresponding structures of ACE with these inhibitors has provided the molecular basis of dual inhibitor recognition involving the catalytic site in both enzymes. This new information will be very useful in the design of safer and more selective vasopeptidase inhibitors of NEP and ACE for effective treatment in hypertension and heart failure.

The effect of the plasma membrane on the activity of angiotensin-I converting enzyme (ACE) plays a crucial role in the evaluation of food-derived ACE inhibitory peptides, although these peptides are commonly evaluated in the system with ACE in its free state. In this study, we constructed an in vitro membrane-bound ACE C domain system to simulate the presence of the plasma membrane. The resultant K m and V max suggested that the presence of the membrane reduced the affinity between ACE C domain and hippuryl-histidyl-leucine, while it increased the reaction velocity. The ACE inhibitory activity of four egg white peptides and five structurally modified peptides suggested that a moderate hydrophobicity/hydrophilicity of the peptide is beneficial for the improvement of their ACE inhibitory activity in a membrane-bound system. These results also indicated that the N terminal plays a significant role in the ACE inhibitory activity of peptides in the membrane-bound system.

Hypertension is a diverse illness interlinked with cerebral, cardiovascular (CVS) and renal abnormalities. Presently, the malady is being treated by focusing on Renin- angiotensin system (RAS), voltage-gated calcium channels, peripheral vasodilators, renal and sympathetic nervous systems. Cardiovascular and renal abnormalities are associated with the overactivation of RAS, which can be constrained by angiotensin- converting enzyme inhibitors (ACEIs), angiotensin II (Ang-II) -AT1 receptor blockers (ARBs) and renin inhibitors. The latter is a new player in the old system. The renin catalyzes the conversion of angiotensinogen to Angiotensin I (Ang-I). This can be overcome by inhibiting renin, a preliminary step, eventually hinders the occurrence of the cascade of events in the RAS. Various peptidomimetics, the first-generation renin inhibitors developed six decades ago have limited drug-like properties as they suffered from poor intestinal absorption, high liver first-pass metabolism and low oral bioavailability. The development of chemically diverse molecules from peptides to nonpeptides expanded the horizon to achieving direct renin inhibition. Aliskiren, a blockbuster drug that emerged as a clinical candidate and got approved by the US FDA in 2007 was developed by molecular modeling studies. Aliskiren indicated superior to average efficacy and with minor adverse effects relative to other RAS inhibitors. However, its therapeutic use is limited by poor oral bioavailability of less than 2% that is similar to first-generation peptidic compounds. In this review, we present the development of direct renin inhibitors (DRIs) from peptidic to nonpeptidics that lead to the birth of aliskiren, its place in the treatment of cardiovascular diseases and its limitations., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Hibiscus species (Malvaceae) have been long used as an antihypertensive folk remedy. The aim of our study was to specify the optimum solvent for extraction of the angiotensin-converting enzyme inhibiting (ACEI) constituents from Hibiscus sabdariffa L. The 80% methanol extract (H2) showed the highest ACEI activity, which exceeds that of the standard captopril (IC50 0.01255 ± 0.00343 and 0.210 ± 0.005 µg/mL, respectively). Additionally, in a comprehensive metabolomics approach, an ultra-performance liquid chromatography (UPLC) coupled to the high resolution tandem mass spectrometry (HRMS) method was used to trace the metabolites from each extraction method. Interestingly, our comprehensive analysis showed that the 80% methanol extract was predominated with secondary metabolites from all classes including flavonoids, anthocyanins, phenolic and organic acids. Among the detected metabolites, phenolic acids such as ferulic and chlorogenic acids, organic acids such as citrate derivatives and flavonoids such as kaempferol have been positively correlated to the antihypertensive potential. These results indicates that these compounds may significantly contribute synergistically to the ACE inhibitory activity of the 80% methanol extract.

Angiotensin-converting enzyme (ACE) is best known for its formation of the vasopressor angiotensin II that controls blood pressure but is also involved in other physiological functions through the hydrolysis of a variety of peptide substrates. The enzyme contains two catalytic domains (nACE and cACE) that have different affinities for ACE substrates and inhibitors. We investigated whether nACE inhibitor backbones contain a unique property which allows them to take advantage of the hinging of nACE. Kinetic analysis showed that mutation of unique nACE residues, in both the S2 pocket and around the prime subsites (S') to their C-domain counterparts, each resulted in a decrease in the affinity of nACE specific inhibitors (SG6, 33RE and ketoACE-13) but it required the combined S2&#95;S' mutant to abrogate nACE-selectivity. However, this was not observed with the non-domain-selective inhibitors enalaprilat and omapatrilat. High-resolution structures were determined for the minimally glycosylated nACE with the combined S2&#95;S' mutations in complex with the ACE inhibitors 33RE (1.8 Å), omapatrilat (1.8 Å) and SG6 (1.7 Å). These confirmed that the affinities of the nACE-selective SG6, 33RE and ketoACE-13 are not only affected by direct interactions with the immediate environment of the binding site, but also by more distal residues. This study provides evidence for a more general mechanism of ACE inhibition involving synergistic effects of not only the S2, S1' and S2' subsites, but also residues involved in the sub-domain interface that effect the unique ways in which the two domains stabilize active site loops to favour inhibitor binding., (© 2020 The Author(s).)

Microalgae are primary producers with multiple nutrients in aquatic environments and mostly have applications in biological feed and fuel industry. There are few studies assessing the angiotensin-I-converting enzyme (ACE) inhibition potential of Isochrysis zhanjiangensis , other than its antioxidant potential. In this study, we evaluated a peptide from I. zhanjiangensis (PIZ, FEIHCC) and its vascular endothelial factors and mechanism in human umbilical vein endothelial cells (HUVEC). The results reveal that PIZ (IC 50 = 61.38 μM) acts against ACE in a non-competitive binding mode. In addition, PIZ inhibits angiotensin II (Ang II)-induced vascular factor secretion and expression by blocking inflammation and apoptosis through nuclear factor κB (NF-κB), nuclear erythroid 2-related factor 2 (Nrf2), mitogen-activated protein kinases (MAPKs), and the serine/threonine kinase (Akt) signal pathways. This study reveals that PIZ has potential to be developed as a therapeutic agent for hypertension and provides a new method of high-value utilization of I. zhanjiangensis .

The isolation and purification of active components from the brown algae Sargassum.wightii is highly limited. In the present study, fucoxanthin was purified from S. wightii using simple methods. Ethyl acetate fraction obtained by Soxhlet extraction contained high concentration of fucoxanthin. Fucoxanthin-rich fraction was further subjected to open silica column chromatography and thin layer chromatography to obtain purified fucoxanthin. Purified fucoxanthin showed in vitro antioxidant activity. Fucoxanthin showed inhibition of angiotensin I-converting enzyme (ACE) with half maximal inhibitory value of 822.64 ± 17.69 μM. Kinetic analysis revealed mixed non-competitive inhibition with inhibitory constant of 600 μM for fucoxanthin against ACE. Molecular docking analysis showed the interaction of fucoxanthin with amino acids and zinc ion present in the active site of the human ACE. Molecular dynamics analysis demonstrated the stability of the fucoxanthin and ACE complex in in silico. These results show that S. wightii may be used as food ingredient to overcome hypertension., Competing Interests: Declaration of competing interest All the authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Angiotensin-I converting enzyme (ACE) is a zinc metallopeptidase that has an important role in regulating the renin-angiotensin-aldosterone system (RAAS). It is also an important drug target for the management of cardiovascular diseases. Hemorphins are endogenous peptides that are produced by proteolytic cleavage of beta hemoglobin. A number of studies have reported various therapeutic activities of hemorphins. Previous reports have shown antihypertensive action of hemorphins via the inhibition of ACE. The sequence of hemorphins is highly conserved among mammals, except in camels, which harbors a unique Q>R variation in the peptide. Here, we studied the ACE inhibitory activity of camel hemorphins (LVVYPWTRRF and YPWTRRF) and non-camel hemorphins (LVVYPWTQRF and YPWTQRF). Computational methods were used to determine the most likely binding pose and binding affinity of both camel and non-camel hemorphins within the active site of ACE. Molecular dynamics simulations showed that the peptides interacted with critical residues in the active site of ACE. Notably, camel hemorphins showed higher binding affinity and sustained interactions with all three subsites of the ACE active site. An in vitro ACE inhibition assay showed that the IC 50 of camel hemorphins were significantly lower than the IC 50 of non-camel hemorphins.

The synthetic Angiotensin Converting Enzyme (ACE) inhibitors have side effects and hence demands for natural ACE inhibitors have been rising. The aim of this study is to purify and introduce natural ACE inhibitors extracted from Zizyphus jujuba fruits. Proteins from Zizyphus jujuba were lysed by trypsin, papain and their combination. Acquired peptides were purified and evaluated for ACE inhibitory activity. Peptide fractions with inhibitory activity were sequenced using tandem mass spectrometry. To elucidate the mode of peptide binding to ACE, homology modeling, molecular docking and molecular dynamics simulation were performed. Amino acid sequence of F2 and F4 peptides, which were the most active hydrolysates, were determined to be IER and IGK with the IC 50 values of 0.060 and 0.072 mg/ml, respectively. Results obtained by computational analysis revealed that similar to the common ACE competitive inhibitors such as captopril, IER tripeptide binds to the enzyme active site, in vicinity of the zinc binding site, and occupies the S1 and S2' subsites. Binding occurs through hydrogen bonding with Gln293, Lys522, His524, Tyr531 and also several hydrophobic interactions. Collectively, these findings indicate that IER tripeptide inhibits the rabbit ACE enzyme through a competitive mechanism of inhibition with IC 50 values in the millimolar range.

This study evaluated the biological properties of peptides from brown rice protein hydrolyzed by bromelain (eb-RPH) in relation to flavor characteristic. The fractionation into peptides < 1 kDa was observed to improve the DPPH, ABTS, and hydroxyl radical-scavenging activities (0.19, 2.28, and 24.64 mM Trolox, respectively), angiotensin-converting enzyme (ACE)-inhibitory activity (IC 50 value of 0.20 ± 0.011 mg protein/mL), as well as bitter and umami tastes. The < 1 kDa fraction was further analyzed by liquid chromatography-electrospray ionization/mass spectrometry to identify amino acid sequence associated with biological activities and flavor characteristics. Eight peptides were identified. Most of the identified peptides contained features of previously reported ACE inhibitory and antioxidant peptides, especially peptide FGGSGGPGG and FGGGGAGAGG. Evaluation of flavor characteristics using BIOPEP database demonstrated that they had high occurrence frequencies of umami peptides (ESDVVSDL, GSGVGGAK, and SSVGGGSAG) and low Q-value (938.75 to 282.22), suggesting that these peptides may be used as a fortifying health ingredient with good taste. PRACTICAL APPLICATION: The fractionated brown rice protein hydrolysate (< 1 kDa) has the potential to serve as a functional food ingredient in nutraceutical food and beverage products that can provide health benefits with good taste. Information on amino acid composition and spatial conformation of peptide may aid us to better understand the molecular mechanisms involved in bioactivities and flavor of brown rice peptide for industrial applications., (© 2020 Institute of Food Technologists®.)

We evaluated the acute (single-dose) and subacute (repeated-dose) oral toxicity of alcalase-hydrolyzed whey protein concentrate. Our acute study revealed no death or treatment-related complications, and the median lethal dose of whey protein concentrate hydrolysate was >2,500 mg/kg. In the subacute study, when the hydrolysate was fed at 3 different concentrations (200, 400, and 800 mg/kg), no groups showed toxicity changes compared with controls. Then, whey protein concentrate hydrolysate was orally administered to spontaneously hypertensive rats. Results revealed significant reductions in blood pressure in a dose-dependent manner, and dosing at 400 mg/kg led to significant blood pressure reduction (-47.8 mm Hg) compared with controls (blood pressure maintained) and the findings of previous work (-21 mm Hg). Eight peptides-RHPEYAVSVLLR, GGAPPAGRL, GPPLPRL, ELKPTPEGDL, VLSELPEP, DAQSAPLRVY, RDMPIQAF, and LEQVLPRD-were sequentially identified and characterized. Of the peptides, VLSELPEP and LEQVLPRD showed the most prominent in vitro angiotensin-I converting enzyme inhibition with half-maximal inhibitory concentrations of 0.049 and 0.043 mM, respectively. These findings establish strong evidence for the in vitro and in vivo potential of whey protein concentrate hydrolysate to act as a safe, natural functional food ingredient that exerts antihypertensive activity., (Copyright © 2020 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The objective of the study was to mask the unpleasant taste of captopril (CPT). Taste masking was achieved by complexation of CPT with a basic ion exchange resin, Dowex ® 66, using the batch method. Dowex ® 66 was used for the adsorption of CPT, and physical and chemical parameters of the CPT resinates complex were evaluated. A central composite design was used to generate the experiments for the manufacture of resinates using different process and formulation variables. In vitro dissolution studies were performed for 2 h in 0.01N HCl (pH 1.6) using USP Apparatus I. The compatibility of CPT and the resin was evaluated by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). The resinates were evaluated for micromeritic properties and further characterised using FTIR, DSC, and PXRD. Response surface methodology was used to determine the significance of input variables on the CPT content and release. The CPT resin ratio was found to have a significant impact on content of the resinates and on CPT release. The formulations were also studied for taste masking ability by means of an electronic gustatory system - electronic tongue.

Aim: In the present study, beetroot juice was encapsulated in pumpkin protein isolate by freeze and spray drying method. Methods: The powders were characterised by measuring moisture content, hygroscopicity, bulk density, solubility, a* value (colour). To simulate the human gastrointestinal digestion, in vitro digestion was conducted as two-stage hydrolysis by pepsin and by pancreatin. The antioxidant and ACE inhibitory potential of the digests was examined. Results: Encapsulation efficiency of phenols from beetroot juice in pumpkin protein isolate was 92% for freeze and 75% for spray dried. Physical properties of all samples were affected by the drying methods. All powders were easily digested. It was observed that the antioxidant and ACE inhibitory potential of the digests was enhanced, indicating that it originated from the hydrolysates released from the protein carrier during digestion. Conclusion: The results from this study are promising and indicate that the pumpkin oil cake protein has great potential and could be introduced to the encapsulation process of bioactive compounds as a new carrier agent.

IAVPTGVA (Soy1) and LPYP are two soybean peptides, which display a multifunctional behavior, showing in vitro hypocholesterolemic and hypoglycemic activities. A preliminary screening of their structures using BIOPEP suggested that they might be potential angiotensin-converting enzyme (ACE) inhibitors. Therefore, a bottom-up-aided approach was developed in order to clarify the in vitro hypotensive activity. Soy1 and LPYP dropped the intestinal and renal ACE enzyme activity with IC 50 values equal to 14.7 ± 0.28 and 5.0 ± 0.28 μM (Caco-2 cells), and 6.0 ± 0.35 and 6.8 ± 0.20 μM (HK-2 cells), respectively. In parallel, a molecular modeling study suggested their capability to act as competitive inhibitors of this enzyme. Finally, in order to increase both their stability and hypotensive properties, a suitable strategy for the harmless control of their release from a nanomaterial was developed through their encapsulation into the RADA16-assembling peptide.

Hypertension is considered as one of the most common diseases that affect human beings (both male and female) due to its high prevalence and also extending widely to both industrialize and developing countries. Angiotensin-converting enzyme (ACE) has a significant role in the regulation of blood pressure and ACE inhibition with inhibitory peptides is considered as a major target to prevent hypertension. In the current study, a blood pressure regulating honey protein (MRJP1) was examined to identify the ACE inhibitory peptides. The 3D structure of MRJP1 was predicted by utilizing the threading approach and further optimized by performing molecular dynamics simulation for 30 nanoseconds (ns) to improve the quality factor up to 92.43%. Root mean square deviation and root mean square fluctuations were calculated to evaluate the structural features and observed the fluctuations in the timescale of 30 ns. AHTpin server based on scoring vector machine of regression models, proteolysis and structural characterization approaches were implemented to identify the potential inhibitory peptides. The anti-hypertensive peptides were scrutinized based on the QSAR models of anti-hypertensive activity and the molecular docking analyses were performed to explore the binding affinities and potential interacting residues. The peptide "EALPHVPIFDR" showed the strong binding affinity and higher anti-hypertensive activity along with the global energy of -58.29 and docking score of 9590. The aromatic amino acids especially Tyr was observed as the key residue to design the dietary peptides and drugs like ACE inhibitors., Competing Interests: The authors have declared that no competing interests exist.

This study investigated the effects of Lactobacillus plantarum (Lp) and Bifidobacterium animalis ssp. lactis (Ba) in co-cultures with Streptococcus thermophilus (St) on changes in the acidification profile, proteolytic activity, peptide production, in vitro antioxidant activity, and angiotensin-converting enzyme (ACE) inhibitory properties of fermented milks during 21 d of storage at 4°C. The pH values and proteolysis in all batches showed a gradual decrease and increase during storage, respectively. The ACE-inhibitory activity and total antioxidant capacity of all co-fermented milk samples followed a similar pattern, with maximum values on d 6 of storage. The St starter, in conjunction with Ba or Lp or both, enhanced proteolysis, peptide generation, and ACE-inhibitory and antioxidant activity, but decreased pH values compared with St alone. The St-Ba-Lp samples showed higher DPPH • (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, hydroxyl radical scavenging activity, and total antioxidant capacity, but similar superoxide anion scavenging activity compared to St-Ba or St-Lp samples. The St-Ba samples showed higher DPPH • radical scavenging activity but lower hydroxyl radical scavenging activity than St-Lp samples. In the ACE-inhibitory assays, the St-Lp samples exhibited relatively low activity among the co-fermented milks, digested or not. The presence of Ba and Lp in fermentation together did not affect ACE-inhibitory activity in undigested fermented milks compared with the presence of Ba alone, and St-Ba-Lp fermented milks demonstrated an increase in ACE-inhibitory activity after simulated gastrointestinal digestion in storage. Pepsin digestion largely improved ACE-inhibitory activity, except in St-Lp samples, in which the activity was reduced. Further hydrolysis by trypsin reduced final activity in digestion. This study suggests that co-cultured fermentation with probiotics improves in vitro antioxidant and ACE inhibition activity in fermented milks, and this effect is partly due to the higher proteolytic activity of probiotics., (Copyright © 2020 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Recently, we developed a bradykinin reporter assay and demonstrated the differing protease activity in Complex Regional Pain Syndrome patients vs. controls. In order to further characterize CRPS pathophysiology, the neuropeptide substance P was evaluated as possible reporter substance, here. It was labeled with a chromophore at the lysine residue and generated two major fragments following incubation with serum (amino acid residues 3-8 and 3-11) which were reproducibly separated by thin-layer chromatography. Dabsylated substance P was shown to be a substrate of angiotensin-converting enzyme. The combination of both bradykinin and substance P reporter substances with specific enzyme inhibitors will shed more light on biochemical pathways in inflammatory processes and pain. Comparative clinical studies are now needed to define the application range of both assays in more detail., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Several milk/whey derived peptides possess high in vitro angiotensin I-converting enzyme (ACE) inhibitory activity. However, in some cases, poor correlation between the in vitro ACE inhibitory activity and the in vivo antihypertensive activity has been observed. The aim of this study is to gain insight into the structure-activity relationship of peptide sequences present in whey/milk protein hydrolysates with high ACE inhibitory activity, which could lead to a better understanding and prediction of their in vivo antihypertensive activity. The potential interactions between peptides produced from whey proteins, previously reported as high ACE inhibitors such as IPP, LIVTQ, IIAE, LVYPFP, and human ACE were assessed using a molecular docking approach. The results show that peptides IIAE, LIVTQ, and LVYPFP formed strong H bonds with the amino acids Gln 259, His 331, and Thr 358 in the active site of the human ACE. Interestingly, the same residues were found to form strong hydrogen bonds with the ACE inhibitory drug Sampatrilat. Furthermore, peptides IIAE and LVYPFP interacted with the amino acid residues Gln 259 and His 331, respectively, also in common with other ACE-inhibitory drugs such as Captopril, Lisinopril and Elanapril. Additionally, IIAE interacted with the amino acid residue Asp 140 in common with Lisinopril, and LIVTQ interacted with Ala 332 in common with both Lisinopril and Elanapril. The peptides produced naturally from whey by enzymatic hydrolysis interacted with residues of the human ACE in common with potent ACE-inhibitory drugs which suggests that these natural peptides may be potent ACE inhibitors.

Momordica charantia (Mc) seeds are widely used edible crop with high nutritional quality. The food and pharmaceutical industries use it as a natural anti-oxygenic agent. Herein, a ~52 kDa protein, which is a major part of seed proteome has been purified, biochemically characterized and structure has been determined. MALDI-ESI-MS identified peptide fragments and contig-deduced sequence suggested the protein to be homologous to 7S globulins. The crystal structure shows that protein has a bicupin fold similar to 7S globulins and the electron density for a copper and acetate ligand were observed in the C-terminal barrel domain. In silico study reveals that a tripeptide (VFK) from Mc7S possess a higher binding affinity for angiotensin converting enzyme (ACE) than already reported drug Lisinopril (LPR). The protein is a glycoprotein and highly stable under varying thermal and pH conditions due to its secondary structures. The DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay showed the protein to have an anti-oxygenic nature and can aid in scavenging free radical from sample. The protein can assist to enhance the nutritional and functional value of food by acting as a food antioxidant. Further, characterization of Mc7S required which might add in importance of Mc7S as antioxidant, anti-diabetic and anti-hypertensive.

In this study, we investigated the antihypertensive effects in vitro and in vivo of novel angiotensin-converting enzyme inhibitory (ACEI) peptides purified and identified from bovine bone gelatin hydrolysate (BGH). Thirteen ACEI peptides were identified from BGH, and among which, RGL-(Hyp)-GL and RGM-(Hyp)-GF exhibited high ACE inhibition with IC 50 values of 1.44 and 10.23 μM. Molecular docking predicted that RGM-(Hyp)-GF and ACE residues of Glu384, His513, and Lys511 formed hydrogen-bonding interactions at distances of 2.57, 2.99, and 2.42 + 3.0 Å. RGL-(Hyp)-GL formed hydrogen bonds with Lys511 and Tyr523 and generated hydrogen-bonding interactions with His387 and Glu411 in the zinc(II) complexation motif at distances of 2.74 and 3.03 + 1.93 Å. The maximal decrements in systolic blood pressure in spontaneously hypertensive rats induced by one-time gavage of RGL-(Hyp)-GL and RGM-(Hyp)-GF at 30 mg/kg were 31.3 and 38.6 mmHg. RGL-(Hyp)-GL had higher enzyme degradation resistance than that of RGM-(Hyp)-GF in vitro incubation in rat plasma, and they were sequentially degraded into pentapeptides and tetrapeptides within 2 h. Our results indicate that BGH can serve as a nutritional candidate to control blood pressure.

Besides their nutritional value, whey protein (WP) peptides are food components retaining important pharmacological properties for controlling hypertension. We herein report how the use of complementary experimental and theoretical investigations allowed the identification of novel angiotensin converting enzyme inhibitory (ACEI) peptides obtained from a WP hydrolysate and addressed the rational design of even shorter sequences based on molecular pruning. Thus, after bromelain digestion followed by a 5 kDa cutoff ultrafiltration, WP hydrolysate with ACEI activity was fractioned by RP-HPLC; 2 out of 23 collected fractions retained ACEI activity and were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In the face of 128 identified peptides, molecular docking was carried out to prioritize peptides and to rationally guide the design of novel shorter and bioactive sequences. Therefore, 11 peptides, consisting of 3-6 amino acids and with molecular weights in the range from 399 to 674 Da, were rationally designed and then purchased to determine the IC 50 value. This approach allowed the identification of two novel peptides: MHI and IAEK with IC 50 ACEI values equal to 11.59 and 25.08 μM, respectively. Interestingly, we also confirmed the well-known ACEI IPAVF with an IC 50 equal to 9.09 μM. In light of these results, this integrated approach could pave the way for high-throughput screening and identification of new peptides in dairy products. In addition, the herein proposed ACEI peptides could be exploited for novel applications both for food production and pharmaceuticals.

Background: In order to utilize tilapia skin gelatin hydrolysate protein, which is normally discarded as industrial waste in the process of fish manufacture, we study the in vivo and in vitro angiotensin-I-converting enzyme (ACE) inhibitory activity of the peptide Leu-Ser-Gly-Tyr-Gly-Pro (LSGYGP). The aim was to provide a pharmacological basis of the development of minimal side effects of ACE inhibitors by comparative analysis with captopril in molecular docking., Results: This peptide from protein-rich wastes showed excellent ACE inhibitory activity (IC 50  = 2.577 μmol L -1 ) and exhibited a mixed noncompetitive inhibitory pattern with Lineweaver-Burk plots. Furthermore, LSGYGP and captopril groups both showed significant decreases in blood pressure after 6 h and maintained good digestive stability over 4 h. Molecular bond interactions differentiate competitive captopril upon hydrogen bond interactions and Zn(II) interaction. The C-terminal Pro generates three interactions (hydrogen bonds, hydrophilic interactions and Van der Waals interactions) in the peptide and effectively interacts with the S1 and S2 pockets of ACE., Conclusion: LSGYGP, with an IC 50 value of 2.577 μmol L -1 , has an antihypertensive effect in spontaneously hypertensive rats. Through comparison with captopril, this study revealed that LSGYGP may be a potential food-derived ACE inhibitory peptide and could act as a functional food ingredient to prevent hypertension. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

The angiotensin-converting enzyme (ACE) is a two-domain dipeptidylcarboxypeptidase, which has a direct involvement in the control of blood pressure by performing the hydrolysis of angiotensin I to produce angiotensin II. At the same time, ACE hydrolyzes other substrates such as the vasodilator peptide bradykinin and the anti-inflammatory peptide N-acetyl-SDKP. In this sense, ACE inhibitors are bioactive substances with potential use as medicinal products for treatment or prevention of hypertension, heart failures, myocardial infarction, and other important diseases. This review examined the most recent literature reporting ACE inhibitors with the help of molecular modeling. The examples exposed here demonstrate that molecular modeling methods, including docking, molecular dynamics (MD) simulations, quantitative structure-activity relationship (QSAR), etc, are essential for a complete structural picture of the mode of action of ACE inhibitors, where molecular docking has a key role. Examples show that too many works identified ACE inhibitory activities of natural peptides and peptides obtained from hydrolysates. In addition, other works report non-peptide compounds extracted from natural sources and synthetic compounds. In all these cases, molecular docking was used to provide explanation of the chemical interactions between inhibitors and the ACE binding sites. For docking applications, most of the examples exposed here do not consider that: (i) ACE has two domains (nACE and cACE) with available X-ray structures, which are relevant for the design of selective inhibitors, and (ii) nACE and cACE binding sites have large dimensions, which leads to non-reliable solutions during docking calculations. In support of the solution of these problems, the structural information found in Protein Data Bank (PDB) was used to perform an interaction fingerprints (IFPs) analysis applied on both nACE and cACE domains. This analysis provides plots that identify the chemical interactions between ligands and both ACE binding sites, which can be used to guide docking experiments in the search of selective natural components or novel drugs. In addition, the use of hydrogen bond constraints in the S 2 and S 2 ' subsites of nACE and cACE are suggested to guarantee that docking solutions are reliable.

The two-domain dipeptidylcarboxypeptidase Angiotensin-I-converting enzyme (EC 3.4.15.1; ACE) plays an important physiological role in blood pressure regulation via the reninangiotensin and kallikrein-kinin systems by converting angiotensin I to the potent vasoconstrictor angiotensin II, and by cleaving a number of other substrates including the vasodilator bradykinin and the anti-inflammatory peptide N-acetyl-SDKP. Therefore, the design of ACE inhibitors is within the priorities of modern medical sciences for treating hypertension, heart failures, myocardial infarction, and other related diseases. Despite the success of ACE inhibitors for the treatment of hypertension and congestive heart failure, they have some adverse effects, which could be attenuated by selective domain inhibition. Crystal structures of both ACE domains (nACE and cACE) reported over the last decades could facilitate the rational drug design of selective inhibitors. In this review, we refer to the history of the discovery of ACE inhibitors, which has been strongly related to the development of molecular modeling methods. We stated that the design of novel selective ACE inhibitors is a challenge for current researchers which requires a thorough understanding of the structure of both ACE domains and the help of molecular modeling methodologies. Finally, we performed a theoretical design of potential selective derivatives of trandolaprilat, a drug approved to treat critical conditions of hypertension, to illustrate how to use molecular modeling methods such as de novo design, docking, Molecular Dynamics (MD) simulations, and free energy calculations for creating novel potential drugs with specific interactions inside nACE and cACE binding sites., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Pharmacological treatment of arterial hypertension in children is mainly based on individual experience, but there is evidence that blocking the angiotensin system reduces systolic and diastolic blood when compared to placebo, and these drugs are safe to use for a short duration, also in children under 6 years of age. Blocking the angiotensin system either by angiotensin-converting enzyme inhibitors or by antagonizing the angiotensin 1 receptor is effective, but did not display a consistent dose-response relationship with escalating doses, but the effective doses are known. Calcium channel antagonists are effective antihypertensives in children, but the evidence is limited. Based on small-sized studies, beta-blockers modestly reduce systolic blood pressure, but have no significant effect on diastolic blood pressure compared to placebo. They act in combination to antagonize reflex tachycardia induced by vasodilators. The most commonly used antihypertensive agents are safe to use in short-term studies.

Background: Drug-protein complexes is one of the crucial factors when analyzing the pharmacokinetics and pharmacodynamics of a drug because they can affect the excretion, distribution, metabolism and interaction with target tissues., Objectives: The aim of this study was to investigate the interaction of human hemoglobin (Hb) and angiotensin I converting enzyme inhibitory peptide (ACEIP) in the absence and presence of different- frequency electromagnetic fields (EMF)., Methods: Various spectroscopic methods like fluorescence spectroscopy, ultraviolet, circular dichroism and conductometry techniques were applied to investigate Hb-ACEIP interaction in the absence and presence of EMF., Result: The presented spectroscopic studies indicated that EMF changed the interaction between Hb and ACEIP. The a-helix content of Hb decreased upon binding to ACEIP and conductivity of the solution enhanced upon binding. Based on Stern-Volmer equations, it could be stated that the Hb-ACEIP affinity was higher in the presence of EMF., Conclusion: It can be concluded that for patients who use the drug to control blood pressure, a low-frequency electromagnetic field would have a positive effect on the uptake of the drug., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Angiotensin converting enzyme (ACE), neutral endopeptidase (NEP) and aminopeptidase N (APN) are responsible for generation of vasoactive peptides that regulates vasoconstriction, vasodilation and natriuresis, which altogether regulate blood pressure. Cumulative inhibition of ACE, NEP and APN effectively blocks the progression of respective pathways. In this study, N-methylated peptide inhibitors F-N(Me)H-L, V-N(Me)F-R and R-N(Me)V-Y were synthesized against ACE, NEP and APN respectively, using their respective physiological substrates. F-N(Me)H-L inhibited ACE activity with an IC 50 of 83 nmol/L, V-N(Me)F-R inhibited NEP activity with an IC 50 of 1.173 μmol/L and R-N(Me)V-Y inhibited APN activity with an IC 50 of 3.94 nmol/L respectively. Further, the anti-hypertensive effect of N-methylated peptides was evaluated using rat model of dexamethasone-induced hypertension. Individual peptides and their cocktail treatment were started from day 6 of the study period and blood pressure was measured on every alternate day during 15 day study. Administration of F-N(Me)H-L (138 ± 3 mmHg) and cocktail of all the three peptides at a dose of 100 mg/kg significantly reduced systolic blood pressure (SBP) compared to dexamethasone group (SBP of Groups-dexamethasone; (167 ± 5 mmHg), F-N(Me)H-L (138 ± 3 mmHg), and Cocktail (122 ± 3 mmHg). Anti-hypertensive, anti-hypertrophic and anti-fibrotic effects of N-methylated peptides and cocktail was further reflected by the decreased levels of circulating Ang II and increased ANP levels in sera of hypertensive rats along with decrease in collagen deposition in heart and kidney. Though, ACE inhibition is adequate to reduce SBP, targeting NEP and APN along with ACE is beneficial in tackling hypertension and associated fibrosis of heart., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Albumin is the major fraction of quinoa protein that is characterized as having high nutritional value. However, until now, scant information is available on the bioactivity of quinoa albumin or its hydrolysates. To promote its usage, we extracted albumin in this study from quinoa bran assisted with cellulase and hemicellulose, and hydrolyzed it by alcalase and trypsin to produce bioactive peptides. The hydrolysates (QBAH) were purified by gel filtration and reversed-phase high-performance liquid chromatography (RP-HPLC), followed by identification using liquid chromatography-mass spectrometry (LC-MS/MS). Furthermore, based on in silico analysis, one angiotensin-I converting enzyme (ACE)-inhibitory and antioxidant peptide, RGQVIYVL (946.6 Da), and two antioxidant peptides, ASPKPSSA (743.8 Da), and QFLLAGR (803.5 Da), from QBAH were synthesized. RGQVIYVL showed a high ACE-inhibitory activity (IC 50 = 38.16 μM) with competitive mode of inhibition, and showed significant antihypertensive effect in spontaneously hypertensive rats at a concentration of 100-150 mg/kg body weight (bw). Molecular docking simulation showed that it could interact with the active ACE site via hydrogen bonds with high binding power. Moreover, RGQVIYVL, ASPKPSSA, and QFLLAGR all demonstrated high ·OH scavenging activity (IC 50 = 61.69-117.46 μM), ABTS + scavenging activity (58.29-74.28%) and Fe 2+ chelating ability (32.54-82.48% at 0.5 mg/mL). They could also retain activity after gastrointestinal enzyme digestion. These results indicate that quinoa albumin is a potential source of bioactive peptides possessing antioxidant and ACE-inhibitory activities.

Background: The use of deer velvet antler (DVA) as a potent traditional medicine ingredient goes back for over 2000 years in Asia. Increasingly, though, DVA is being included as a high protein functional food ingredient in convenient, ready to consume products in Korea and China. As such, it is a potential source of endogenous bioactive peptides and of 'cryptides', i.e. bioactive peptides enzymatically released by endogenous proteases, by processing and/or by gastrointestinal digestion. Fermentation is an example of a processing step known to release bioactive peptides from food proteins. In this study, we aimed to identify in silico bioactive peptides and cryptides in DVA, before and after fermentation, and subsequently to validate the major predicted bioactivity by in vitro analysis., Methods: Peptides that were either free or located within proteins were identified in the DVA samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS) followed by database searching. Bioactive peptides and cryptides were identified in silico by sequence matching against a database of known bioactive peptides. Angiotensin-converting enzyme (ACE) inhibitory activity was measured by a colorimetric method., Results: Three free bioactive peptides (LVVYPW, LVVYPWTQ and VVYPWTQ) were solely found in fermented DVA, the latter two of which are known ACE inhibitors. However matches to multiple ACE inhibitor cryptides were obtained within protein and peptide sequences of both unfermented and fermented DVA. In vitro analysis showed that the ACE inhibitory activity of DVA was more pronounced in the fermented sample, but both unfermented and fermented DVA had similar activity following release of cryptides by simulated gastrointestinal digestion., Conclusions: DVA contains multiple ACE inhibitory peptide sequences that may be released by fermentation or following oral consumption, and which may provide a health benefit through positive effects on the cardiovascular system. The study illustrates the power of in silico combined with in vitro methods for analysis of the effects of processing on bioactive peptides in complex functional ingredients like DVA.

Systematical consumption of functional products has a significant positive effect on health and can reduce the risk of diseases. The aim of this study was to investigate the possibility of using whey protein hydrolysate (WPH) and pumpkin pectin as ingredients in a functional mousse, to evaluate the mousse's antioxidant and hypotensive activities in vitro, and to evaluate the effect of the long-term intake of mousse samples on the progression of hypertension in spontaneously hypertensive rats (SHRs) and on the microbiome status in Wistar rats with antibiotic-induced dysbiosis. The experimental mousse's in vitro antioxidant activity (oxygen radical absorbance capacity) increased by 1.2 times. The hypotensive (angiotensin-1-converting enzyme inhibitory) activity increased by 6 times in comparison with a commercial mousse. Moreover, the addition of pectin allowed the elimination of the bitter aftertaste of WPH. In vivo testing confirmed the hypotensive properties of the experimental mousse. The systolic blood pressure in SHRs decreased by 18 mmHg and diastolic blood pressure by 12 mmHg. The experimental mousse also showed a pronounced bifidogenic effect. The Bifidobacterium spp. population increased by 3.7 times in rats orally administered with the experimental mousse. The results of these studies confirm that WPH and pumpkin pectin are prospective ingredients for the development of functional mousses.

Background: Angiotensin-converting enzyme (ACE) inhibitory peptides were found to alleviate acute hepatitis significantly. In this study, we purified and identified ACE inhibitory peptide from cashew to evaluate its protective role on alcohol-induced acute hepatitis in mice., Results: The ACE inhibitory peptides were purified by using consecutive chromatographic techniques. One of these peptides (FETISFK) exhibited the highest ACE inhibition rate (91.04 ± 0.31%). In vivo, the results showed that ACE inhibitory peptide decreased levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) caused by alcohol exposure. Moreover, it could increase the activities of superoxide dismutase (SOD) and glutathione (GSH), and decrease the level of malondialdehyde (MDA). It was also found to down-regulate markedly the expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). It could also decrease the expression of ACE, angiotensin II (AngII) and angiotensin II type 1 receptor (AT 1 R)., Conclusion: These findings support the view that the ACE inhibitory peptide alleviated acute hepatitis by down-regulating the ACE-AngII-AT 1 R axis, broadening the research approach to prevent acute hepatitis, and providing experimental data for the development and utilization of cashews. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Angiotensin I-converting enzyme (ACE) inhibitory peptides were derived from tuna cooking juice (TCJ) hydrolysis by alcalase in the continuous enzymatic membrane reactor (cEMR) coupling with 1 kDa MWCO membrane. The permeated sample from cEMR for 510 min of hydrolysis was purified by size exclusion chromatography in Sephadex G-25 column. A fraction exhibited the highest ACE inhibitory activity was further separated by RP-HPLC, resulting two fractions showed highest ACE inhibitory activities. The molecular weight (MW) and amino acid sequences of peptides from both fractions were determined using LC-MS/MS. Two potential ACE inhibitory peptides were obtained and showed molecular weight of 959.46 and 1,141.29 Da. PRACTICAL APPLICATIONS: Tuna cooking juice (TCJ) usually was either used as protein source of feed meal or directly discharged to wastewater treatment system. However, it contains water-soluble proteins in a group of sarcoplasmic protein, which is small water-soluble proteins and easily hydrolyzed to small peptides. In this study, the active peptides, angiotensin I-converting enzyme inhibitory peptides (MW of 959.46 and 1,141.29 Da), obtained from TCJ hydrolysate and identified by LC-MS/MS would be a beneficial ingredient for nutraceuticals and functional food against hypertension., (© 2019 Wiley Periodicals, Inc.)

The objective of this work was to obtain casein hydrolysates with aspartic proteinases present in extracts from the artichoke flower (Cynara scolymus L.) and evaluate their antioxidant, antimicrobial, and angiotensin-I converting enzyme (ACE) inhibitory activity in vitro. The casein hydrolysates produced by the action of C. scolymus had elevated antihypertensive and antioxidant activity due to their high hydrophobic peptide content (93.84, 96.58, and 90.54% at 2, 4, and 16 h of hydrolysis, respectively). Hydrolysis time and molecular weight (<3 kDa) had a significant influence on the hypertensive and antioxidant activity of the hydrolysates, which were greater at hydrolysis times of 4 and 16 h and corresponding to the <3 kDa fractions. The <3 kDa fraction of the 16 h hydrolysate had an ACE inhibitory activity with a half-maximal inhibitory concentration (IC 50 ) of 71.77 µg peptides per mL; DPPH and ABTS •+ radical scavenging activities of 6.27 µM and 6.21 mM Trolox equivalents per mg of peptides, respectively; and iron (II) chelation activity with an IC 50 of 221.49 µg of peptides per mL. Antimicrobial activity against Enterococcus faecalis was also observed in the hydrolysates. From the peptide sequences identified in the hydrolysates, we detected 22 peptides (from the BIOPEP database) that were already in their bioactive form (AMKPWIQPK, AMKPWIQPKTKVIPYVRYL, ARHPHPHLSFM, DAQSAPLRVY, FFVAPFPEVFGK, GPVRGPFPII, KVLPVPQK, LLYQEPVLGPVRGPFPIIV, MAIPPKKNQDK, NLHLPLPLL, PAAVRSPAQILQ, RELEELNVPGEIVESLSSSEESITR, RPKHPIKHQ, RPKHPIKHQGLPQEVLNENLLRF, SDIPNPIGSENSEK, TPVVVPPFLQP, VENLHLPLPLL, VKEAMAPK, VLNENLLR, VYPFPGPIH, VYQHQKAMKPWIQPKTKVIPYVRY, VYQHQKAMKPWIQPKTKVIPYVRYL) and are reported to display antioxidant, antimicrobial, and ACE inhibitory activity. We also identified 12,116, 14,513, and 25,169 peptide sequences in the hydrolysates at 2, 4, and 16 h, respectively, that were contained in the primary sequence, and these are reported to display ACE inhibitory, antioxidant, dipeptidyl peptidase IV inhibition, antithrombotic, opioid, immunomodulation, antiamnesic, anticancer, chelating, and hemolytic bioactivity., (Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The current study investigated the angiotensin-converting enzyme (ACE) inhibitory activity of 4 synthetic tripeptides. All the peptides showed enzyme inhibitory activity, especially two promising ones, TTP (Thea-Thea-Pro) and gAgAP (GABA-GABA-Pro), with IC 50 values of 0.92 and 3.4 μmol/L, respectively. Enzyme inhibition kinetics determined by Lineweaver-Burk plots revealed that TTP and gAgAP were competitive inhibitors with Ki values of 0.87 and 3.12 μmol/L, respectively. Molecular docking experiments confirmed that the higher inhibitory potency of TTP and gAgAP might be attributed to the formation of several critical hydrogen bonds with the active site residues in ACE. We further demonstrated that TTP and gAgAP initiated a rapid and significant decrease in systolic blood pressure (SBP) in spontaneously hypertensive rats (SHRs). TTP treatment lowered SBP to the same extent as captopril, although the duration of anti-hypertensive effect was shorter in TTP group than that observed in captopril group. Moreover, the transcription levels of angiotensin II receptor type 1 (agtr1) and miR-132/-212 were downregulated in SHRs after administration of TTP and gAgAP. In particular, TTP treatment caused a comparable reduction of agtr1 levels compared to captopril treatment, while miR-132/212 expression was significantly decreased. These results showed that compound TTP might be served as a potential antihypertensive candidate., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Over the past decades, several studies investigated the health-promoting functions of milk peptides. However, to date many hurdles still exist regarding the widespread use of milk-derived bioactive peptides, as they may be degraded during gastrointestinal digestion. Thus, the aim of our study was to in vitro digest intact whey protein isolate (WPI) and casein proteins (CNP), mimicking in vivo digestion, to investigate their bioactive effects and to identify the potential peptides involved. Whey protein isolate and CNP were digested using a pepsin-pancreatin protocol and ultra-filtered (3-kDa cutoff membrane). A permeate (<3 kDa) and a retentate (>3 kDa) were obtained. Soy protein was included as a control (CTR). Angiotensin-1-converting enzyme inhibitory (ACE1-I) and antioxidant activity (AOX) were assessed and compared with those observed in undigested proteins and CTR. Furthermore, the permeate was characterized by nano-liquid chromatography electrospray ionization tandem mass spectrometry (LC-nano ESI MS/MS) using a shotgun peptidomic approach, and retentate was further digested with trypsin and analyzed by MS using a shotgun proteomic approach to identify potentially bioactive peptides. Further, the effects of WPI, CNP, and CTR retentate on cell metabolic activity and on mucus production (MUC5AC and MUC2 gene expression) were assessed in intestinal goblet HT29-MTX-E12 cells. Results showed that WPI permeate induced a significant ACE1-I inhibitory effect [49.2 ± 0.64% (SEM)] compared with undigested WPI, CNP permeate, and retentate or CTR permeate (10.40 ± 1.07%). A significant increase in AOX (1.58 ± 0.04 and 1.61 ± 0.02 µmol of trolox AOX equivalents per mg of protein, respectively) upon digestion was found in WPI. Potentially bioactive peptides associated with ACE1-I and antihypertensive effects were identified in WPI permeate and CNP retentate. At specific concentrations, WPI, CNP, and CTR retentate were able to stimulate metabolic activity in HT29-MTX-E12 cells. Expression of MUC5AC was increased by CNP retentate and unaltered by WPI retentate; MUC2 expression was significantly increased by 0.33 mg/g of CNP and reduced by 1.33 mg/g of CNP. Our results confirm that milk proteins may be rich sources of bioactive compounds, with the greatest beneficial potential of CNP at the intestinal goblet cell level., (Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Dietary protein peptides from quinoa yoghurt beverage (QYB) fermented with probiotic lactic acid bacteria strains play a protective role against diabetes and hypertension. In this study, the α-glucosidase and ACE inhibitory activities of germination-based protein hydrolysates of QYB were investigated. All protein hydrolysates exhibited a dose and strain-dependent inhibition on the enzymes. The inhibition of α-glucosidase was the highest in QLCSY13 (IC 50  = 8.86 mg/mL), while ACE inhibition was the highest in QLCZ (IC 50  = 0.03 mg/mL). Overall, QLCSY13 had the highest inhibitory activities, which was ascribed to its relatively higher amino acid contents and hydrophobicity. In addition, the ACE and α-glucosidase inhibitory activities of peptide fractions identified by RP-HPLC were 127 ± 4.29 mg/mL and 10.39 ± 4.73 mg/mL respectively. Among the potent inhibitory peptide sequences identified, both LAHMIVAGA and VAHPVF significantly had α-glucosidase and ACE inhibitory activities. Consequently, dietary protein peptides present in QYB had anti-hypertensive and anti-diabetic potentials., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The mosquitoes of the Anopheles and Aedes genus are some of the most deadly insects to humans because of their effectiveness as vectors of malaria and a range of arboviruses, including yellow fever, dengue, chikungunya, West Nile and Zika. The use of insecticides from different chemical classes is a key component of the integrated strategy against An. gambiae and Ae. aegypti, but the problem of insecticide resistance means that new compounds with different modes of action are urgently needed to replace chemicals that fail to control resistant mosquito populations. We have previously shown that feeding inhibitors of peptidyl dipeptidase A to both An. gambiae and Ae. aegypti mosquito larvae lead to stunted growth and mortality. However, these compounds were designed to inhibit the mammalian form of the enzyme (angiotensin-converting enzyme, ACE) and hence can have lower potency and lack selectivity as inhibitors of the insect peptidase. Thus, for the development of inhibitors of practical value in killing mosquito larvae, it is important to design new compounds that are both potent and highly selective. Here, we report the first structures of AnoACE2 from An. gambiae in its native form and with a bound human ACE inhibitor fosinoprilat. A comparison of these structures with human ACE (sACE) and an insect ACE homologue from Drosophila melanogaster (AnCE) revealed that the AnoACE2 structure is more similar to AnCE. In addition, important elements that differ in these structures provide information that could potentially be utilised in the design of chemical leads for selective mosquitocide development., (© 2019 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

A strategy for the continuous flow synthesis of angiotensin converting enzyme (ACE) inhibitors is described. An optimization effort guided by in situ IR analysis resulted in a general amide coupling approach facilitated by N-carboxyanhydride (NCA) activation that was further characterized by reaction kinetics analysis in batch. The three-step continuous process was demonstrated by synthesizing 8 different ACE inhibitors in up to 88 % yield with throughputs in the range of ≈0.5 g h -1 , all while avoiding both isolation of reactive intermediates and process intensive reaction conditions. The process was further developed by preparing enalapril, a World Health Organization (WHO) essential medicine, in an industrially relevant flow platform that scaled throughput to ≈1 g h -1 ., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The bioactivity of ten traditional Korean Angelica species were screened by angiotensin-converting enzyme (ACE) assay in vitro. Among the crude extracts, the methanol extract of Angelica decursiva whole plants exhibited potent inhibitory effects against ACE. In addition, the ACE inhibitory activity of coumarins 1 - 5 , 8 - 18 was evaluated, along with two phenolic acids ( 6 , 7 ) obtained from A . decursiva . Among profound coumarins, 11 - 18 were determined to manifest marked inhibitory activity against ACE with IC 50 values of 4.68-20.04 µM. Compounds 12 , 13 , and 15 displayed competitive inhibition against ACE. Molecular docking studies confirmed that coumarins inhibited ACE via many hydrogen bond and hydrophobic interactions with catalytic residues and zinc ion of C- and N-domain ACE that blocked the catalytic activity of ACE. The results derived from these computational and in vitro experiments give additional scientific support to the anecdotal use of A. decursiva in traditional medicine to treat cardiovascular diseases such as hypertension.