Optimization of the Enzymatic Hydrolysis of Lupin (Lupinus) Proteins for Producing ACE-Inhibitory Peptides

A Review of Bioactive Compound Effects from Primary Legume Protein Sources in Human and Animal Health

The global demand for sustainable and nutritious food sources has catalyzed interest in legumes, known for their rich repertoire of health-promoting compounds. This review delves into the diverse array of bioactive peptides, protein subunits, isoflavones, antinutritional factors, and saponins found in the primary legume protein sources-soybeans, peas, chickpeas, and mung beans. The current state of research on these compounds is critically evaluated, with an emphasis on the potential health benefits, ranging from antioxidant and anticancer properties to the management of chronic diseases such as diabetes and hypertension. The extensively studied soybean is highlighted and the relatively unexplored potential of other legumes is also included, pointing to a significant, underutilized resource for developing health-enhancing foods. The review advocates for future interdisciplinary research to further unravel the mechanisms of action of these bioactive compounds and to explore their synergistic effects. The ultimate goal is to leverage the full spectrum of benefits offered by legumes, not only to advance human health but also to contribute to the sustainability of food systems. By providing a comprehensive overview of the nutraceutical potential of legumes, this manuscript sets a foundation for future investigations aimed at optimizing the use of legumes in the global pursuit of health and nutritional security.

In silico and in vivo experiment of soymilk peptide (tetrapeptide - FFYY) for the treatment of hypertension

Enzyme-Treated Soymilk (ETS) was produced from Commercial Soymilk (CSM) with the treatment of proteinase PROTIN SD-NY10 (Bacillus amyloliquefaciens). Previously, we have isolated novel peptides from ETS but data related to isolated-peptides are scant. In this study, bio-informatics and in vivo analysis of isolated-peptides showed strong binding affinity to the active site of the Angiotensin Converting Enzyme (ACE). Among four peptides, tetrapeptide Phe-Phe-Tyr-Tyr (FFYY) showed strong binding affinity and inhibitory activity to the ACE-enzyme (binding affinity -9.5 Kcal/mol and inhibitory concentration of 1.9 µM respectively) as well as showed less toxicity compared to other peptides. The animal experiment revealed that single oral dose of FFYY (80 µg/kg body weight/day) effectively ameliorates the systolic, diastolic and mean blood pressure in the spontaneously hypertensive rat (SHR) model. Chronic oral administration of FFYY (80 µg/kg body weight/day for 3 weeks) reduced the systolic blood pressure elevation and ACE activity without any adverse side effects on the physiological and biological parameters of SHR. In conclusion, both in silico and in vivo experiments of soymilk-isolated FFYY peptide showed a promising option as a potential alternative for hypertension treatment without adverse side effects on SHR.

Hempseed protein-derived short- and medium-chain peptides and their multifunctional properties

Nowadays, the growing knowledge about the high nutritional value and potential functionality of hempseeds, the edible fruits of the Cannabis sativa L. plant, has sparked a surge in interest in exploring the worthwhile attributes of hempseed proteins and peptides. This trend aligns with the increasing popularity of hemp-based food, assuming a vital role in the global food chain. This chapter targets the nutritional and chemical composition of hempseed in terms of short- and medium-chain bioactive peptides. The analytical approaches for their characterization and multifunctional properties are summarized in detail. Moreover, the processing, functionality, and application of various hempseed protein products are discussed. In the final part of the chapter-for evaluating their propensity to be transported by intestinal cells-the transepithelial transport of peptides within hempseed protein hydrolysate is highlighted.

Evaluation of the multifunctional dipeptidyl-peptidase IV and angiotensin converting enzyme inhibitory properties of a casein hydrolysate using cell-free and cell-based assays

The objective of the study was the evaluation of the potential pleiotropic effect of a commercial casein hydrolysate (CH). After an analysis of the composition, the BIOPEP-UWM database suggested that these peptides contained numerous sequences with potential inhibitory activities on angiotensin converting enzyme (ACE) and dipeptidyl-peptidase IV (DPP-IV). The anti-diabetic and anti-hypertensive effects of these peptides were thus assessed using either cell-free or cell-based assays. In the cell-free system, CH displayed inhibitory properties against DPP-IV (IC₅₀ value equal to 0.38 ± 0.01 mg/mL) and ACE (IC₅₀ value equal to 0.39 ± 0.01 mg/mL). Further, CH reduced the DPP-IV and ACE activities expressed by human intestinal Caco-2 cells by 61.10 ± 1.70% and 76.90 ± 4.47%, respectively, versus untreated cells, after 6 h of treatment at the concentration of 5 mg/mL. This first demonstration of the multifunctional behavior of this material suggests that it may become an anti-diabetic and/or anti-hypertensive ingredient to be included in the formulation of different functional food or nutraceutics.

Rainbow Trout (Oncorhynchus mykiss) as Source of Multifunctional Peptides with Antioxidant, ACE and DPP-IV Inhibitory Activities

The present study aimed at characterizing the possible biological activities of the multifunctional low molecular weight fractions (<3 kDa) peptides isolated from rainbow trout (Oncorhynchus mykiss) obtained by enzymatic hydrolysis. The fish protein hydrolysate (FPH) was tested for its antioxidant property along with its angiotensin converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibitory activities. In particular, the 2,2-diphenyl-1-picrylhydrazyl (DPPH), the ferric reducing antioxidant power (FRAP), the oxygen radical absorbance capacity (ORAC) assay and the 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays were carried out for the evaluation of the in vitro antioxidant activity. The cell-free ACE and DPP-IV inhibitory activity assays were also estimated, showing a dose-dependent inhibition. These biological properties were additionally quantified at the cellular level using human intestinal Caco-2 cells. Namely, the antioxidant activity was determined by evaluating the capability of the hydrolysate to reduce the H₂O₂-induced reactive oxygen species (ROS) and lipid peroxidation levels, and the DPP-IV activity assays show a reduction of enzyme activity of up to 27.57 ± 3.7% at 5 mg/mL. The results indicate that Oncorhynchus mykiss-derived peptides may have potential employment as health-promoting ingredients.

Isolation and functional characterization of hemp seed protein-derived short- and medium-chain peptide mixtures with multifunctional properties for metabolic syndrome prevention

This study aims to obtain a valuable mixture of short-chain peptides from hempseed as a new ingredient for developing nutraceutical and functional foods useful for preventing metabolic syndrome that represents the major cause of death globally. A dedicated analytical platform based on a purification step by size exclusion chromatography or ultrafiltration membrane and high-resolution mass spectrometry was developed to isolate and comprehensively characterize short-chain peptides leading to the identification of more than 500 short-chain peptides. Our results indicated that the short-chain peptide mixture was about three times more active than the medium-chain peptide mixture and total hydrolysate with respect to measured inhibition of the angiotensin-converting enzyme. The short-chain peptide mixture was also two times more active as a dipeptidyl peptidase IV, and twofold more active on the cholesterol metabolism pathway through the modulation of low-density lipoprotein receptor.

Mechanistic Insights into Angiotensin I-Converting Enzyme Inhibitory Tripeptides to Decipher the Chemical Basis of Their Activity

Food proteins are an important source of bioactive peptides, and the angiotensin I-converting enzyme (ACE) inhibitors are worthy of attention for their possible beneficial effects in subjects with mild hypertension. However, the chemical basis underpinning their activity is not well-understood, hampering the discovery of novel inhibitory sequences from the plethora of peptides encrypted in food proteins. This work combined computational and in vitro investigations to describe precisely the chemical basis of potent inhibitory tripeptides. A substantial set of previously uncharacterized tripeptides have been investigated in silico and in vitro, and LCP was described for the first time as a potent ACE inhibitory peptide with IC₅₀ values of 8.25 and 6.95 μM in cell-free and cell-based assays, respectively. The outcomes presented could serve to better understand the chemical basis of already characterized potent inhibitory tripeptides or as a blueprint to design novel and potent inhibitory peptides and peptide-like molecules.

Integrated Evaluation of the Multifunctional DPP-IV and ACE Inhibitory Effect of Soybean and Pea Protein Hydrolysates

Nowadays, notwithstanding their nutritional and technological properties, food bioactive peptides from plant sources garner increasing attention for their ability to impart more than one beneficial effect on human health. Legumes, which stand out thanks to their high protein content, represent valuable sources of bioactive peptides. In this context, this study focused on the characterization of the potential pleotropic activity of two commercially available soybean (SH) and pea (PH) protein hydrolysates, respectively. Since the biological activity of a specific protein hydrolysate is strictly correlated with its chemical composition, the first aim of the study was to identify the compositions of the SH and PH peptides. Peptidomic analysis revealed that most of the identified peptides within both mixtures belong to storage proteins. Interestingly, according to the BIOPEP-UWM database, all the peptides contain more than one active motive with known inhibitory angiotensin converting enzyme (ACE) and dipeptidyl-dipeptidases (DPP)-IV sequences. Indeed, the results indicated that both SH and PH inhibit DPP-IV and ACE activity with a dose-response trend and IC50 values equal to 1.15 ± 0.004 and 1.33 ± 0.004 mg/mL, and 0.33 ± 0.01 and 0.61 ± 0.05 mg/mL, respectively. In addition, both hydrolysates reduced the activity of DPP-IV and ACE enzymes which are expressed on the surface of human intestinal Caco-2 cells. These findings clearly support that notion that SH and PH may represent new ingredients with anti-diabetic and hypotensive effects for the development of innovative multifunctional foods and/or nutraceuticals for the prevention of metabolic syndrome.

Bioactive Peptides from Lupinus spp. Seed Proteins-State-of-the-Art and Perspectives

Nowadays, the search for food-suitable plant proteins is a great challenge. In addition to their sustainability and nutritional value, the focus is more and more on possible positive interactions with human health. To date, the presence of bioactive peptides encrypted in the structure of protein opens new perspectives, addressing the food industry’s request for new ingredients with technological properties and also the nutraceutical and pharmaceutical sectors based on multifunctional health applications. Lupinus is a sustainable genus of the legume family Fabaceae, and the lupin seed-derived bioactive peptides have demonstrated different effects including anti-inflammatory, antidiabetic, antioxidant, antibacterial, hypocholesterolemic, and antihypertensive activities. This review aims to discuss the current knowledge on lupin protein and their bioactive peptides, highlighting the documented health claims, but also the possibility of allergenicity and the work to be done for the development of new functional products.

Gel-Forming of Self-Assembling Peptides Functionalized with Food Bioactive Motifs Modulate DPP-IV and ACE Inhibitory Activity in Human Intestinal Caco-2 Cells

Food bioactive peptides are increasingly used for formulating food products, nutraceuticals, and functional food, since they are generally considered safe for human consumption and metabolic syndrome prevention. They are also becoming popular as sustainable sources of novel functional biomaterials such as hydrogels, edible nanonutraceuticals, delivery systems, and packing materials. However, such food peptides are mostly unstable, and degrade during food processing, or in a gastrointestinal environment, thus resulting in low bioavailability precluding their practical applications. Here, we decided to functionalize the well-known and characterized self-assembling peptide RADA16 with two synthetic analogues of food bioactive peptides deriving from the hydrolysis of soybean glycinin and lupin β-conglutin (namely IAVPTGVA and LTFPGSAED) for control of and improvement in their gel-forming nanostructures, biomechanics, and biological features. Extensive characterization was performed via Circular Dichroism (CD) spectroscopy, Fourier Transform Infrared spectroscopy (FT-IR), Thioflavin T (ThT) binding assay, rheological measurements, and Atomic Force Microscopy (AFM) analysis. Lastly, since self-assembling peptides (SAPs) can be co-assembled with diluent SAPs (without a bioactive epitope) as an approach to control the density of biological signals and therefore attain enhanced bioactivity, we investigated the effect of the co-assembly of RADA16 and functionalized food bioactive SAPs (dubbed cAP-Soy1 and cAP-Lup1) for the growth of Caco-2 human intestinal cells and contextually we characterized their biological activities as DPP-IV and ACE inhibitors, in order to demonstrate their potential use for the prevention of metabolic syndrome.

A heuristic, computer-driven and top-down approach to identify novel bioactive peptides: A proof-of-principle on angiotensin I converting enzyme inhibitory peptides

Bioactive peptides are short peptides (3-20 amino acid residues in length) endowed of specific biological activities. The identification and characterization of bioactive peptides of food origin are crucial to better understand the physiological consequences of food, as well as to design novel foods, ingredients, supplements, and diets to counteract mild metabolic disorders. For this reason, the identification of bioactive peptides is also relevant from a pharmaceutical standpoint. Nevertheless, the systematic identification of bioactive sequences of food origin is still challenging and relies mainly on the so defined "bottom-up" approaches, which rarely results in the total identification of most active sequences. Conversely, "top-down" approaches aim at identifying bioactive sequences with certain features and may be more suitable for the precise identification of very potent bioactive peptides. In this context, this work presents a top-down, computer-assisted and hypothesis-driven identification of potent angiotensin I converting enzyme inhibitory tripeptides, as a proof of principle. A virtual library of 6840 tripeptides was screened in silico to identify potential highly potent inhibitory peptides. Then, computational results were confirmed experimentally and a very potent novel sequence, LMP was identified. LMP showed an IC₅₀ of 15.8 and 6.8 µM in cell-free and cell-based assays, respectively. In addition, a bioinformatics approach was used to search potential food sources of LMP. Yolk proteins were identified as a possible relevant source to analyze in further experiments. Overall, the method presented may represent a powerful and versatile framework for a systematic, high-throughput and top-down identification of bioactive peptides.

Angiotensin-converting enzyme inhibitors from plants: A review of their diversity, modes of action, prospects, and concerns in the management of diabetes-centric complications

Angiotensin-converting enzyme (ACE) inhibitors are antihypertensive medications often used in the treatment of diabetes-related complications. Synthetic ACE inhibitors are known to cause serious side effects like hypotension, renal insufficiency, and hyperkalaemia. Therefore, there has been an intensifying search for natural ACE inhibitors. Many plants or plant-based extracts are known to possess ACE-inhibitory activity. In this review, articles focusing on the natural ACE inhibitors extracted from plants were retrieved from databases like Google Scholar, PubMed, Scopus, and Web of Science. We have found more than 50 plant species with ACE-inhibitory activity. Among them, Angelica keiskei, Momordica charantia, Muntingia calabura, Prunus domestica, and Peperomia pellucida were the most potent, showing comparatively lower half-maximal inhibitory concentration values. Among the bioactive metabolites, peptides (e.g., Tyr-Glu-Pro, Met-Arg-Trp, and Gln-Phe-Tyr-Ala-Val), phenolics (e.g., cyanidin-3-O-sambubioside and delphinidin-3-O-sambubioside), flavonoids ([-]-epicatechin, astilbin, and eupatorin), terpenoids (ursolic acid and oleanolic acid) and alkaloids (berberine and harmaline) isolated from several plant and fungus species were found to possess significant ACE-inhibitory activity. These were also known to possess promising antioxidant, antidiabetic, antihyperlipidemic and anti-inflammatory activities. Considering the minimal side effects and lower toxicity of herbal compounds, development of antihypertensive drugs from these plant extracts or phytocompounds for the treatment of diabetes-associated complications is an important endeavour. This review, therefore, focuses on the ACE inhibitors extracted from different plant sources, their possible mechanisms of action, present status, and any safety concerns.

Angiotensin I-converting enzyme inhibitory peptide: an emerging candidate for vascular dysfunction therapy

Abnormal vasoconstriction, inflammation, and vascular remodeling can be promoted by angiotensin II (Ang II) in the renin-angiotensin system (RAS), leading to vascular dysfunction diseases such as hypertension and atherosclerosis. Researchers have recently focused on angiotensin I-converting enzyme inhibitory peptides (ACEIPs), that have desirable efficacy in vascular dysfunction therapy due to Ang II reduction by inhibiting ACE activity. Promising methods for the large-scale preparation of ACEIPs include selective enzymatic hydrolysis and microbial fermentation. Thus far, ACEIPs have been widely reported to be hydrolyzed from protein-rich sources, including animals, plants, and marine organisms, while many emerging microorganism-derived ACEIPs are theoretically biosynthesized through the nonribosomal peptide synthase (NRPS) pathway. Notably, vasodilatation, anti-inflammation, and vascular reconstruction reversal of ACEIPs are strongly correlated. However, the related molecular mechanisms underlying signal transduction regulation in vivo remain unclear. We provide a comprehensive update of the ACE-Ang II-G protein-coupled type 1 angiotensin receptor (AT1R) axis signaling and its functional significance for potential translation into therapeutic strategies, particularly targeting AT1R by ACEIPs, as well as specific related signaling pathways. Future studies are expected to verify the biosynthetic regulatory mechanism of ACEIPs via the NRPS pathway, the effect of gut microbiota metabolism on vascular dysfunction and rigorous studies of ACE-Ang II-AT1R signaling pathways mediated by ACEIPs in large animals and humans.

Lupin-Derived Bioactive Peptides: Intestinal Transport, Bioavailability and Health Benefits

There is a renewed interest on the reliance of food-based bioactive compounds as sources of nutritive factors and health-beneficial chemical compounds. Among these food components, several proteins from foods have been shown to promote health and wellness as seen in proteins such as α/γ-conglutins from the seeds of Lupinus species (Lupin), a genus of leguminous plant that are widely used in traditional medicine for treating chronic diseases. Lupin-derived peptides (LDPs) are increasingly being explored and they have been shown to possess multifunctional health improving properties. This paper discusses the intestinal transport, bioavailability and biological activities of LDPs, focusing on molecular mechanisms of action as reported in in vitro, cell culture, animal and human studies. The potentials of several LDPs to demonstrate multitarget mechanism of regulation of glucose and lipid metabolism, chemo- and osteoprotective properties, and antioxidant and anti-inflammatory activities position LDPs as good candidates for nutraceutical development for the prevention and management of medical conditions whose etiology are multifactorial.

Impact of nutraceuticals on markers of systemic inflammation: Potential relevance to cardiovascular diseases - A position paper from the International Lipid Expert Panel (ILEP)

Inflammation is a marker of arterial disease stemming from cholesterol-dependent to -independent molecular mechanisms. In recent years, the role of inflammation in atherogenesis has been underpinned by pharmacological approaches targeting systemic inflammation that have led to a significant reduction in cardiovascular disease (CVD) risk. Although the use of nutraceuticals to prevent CVD has largely focused on lipid-lowering (e.g, red-yeast rice and omega-3 fatty acids), there is growing interest and need, especially now in the time of coronavirus pandemic, in the use of nutraceuticals to reduce inflammatory markers, and potentially the inflammatory CVD burden, however, there is still not enough evidence to confirm this. Indeed, diet is an important lifestyle determinant of health and can influence both systemic and vascular inflammation, to varying extents, according to the individual nutraceutical constituents. Thus, the aim of this Position Paper is to provide the first attempt at recommendations on the use of nutraceuticals with effective anti-inflammatory properties.

Antihypertensive and Immunomodulatory Effects of Defatted Corn Germ Hydrolysates: An in vivo Study

This study investigated the antihypertensive and immunomodulatory effects of defatted corn germ hydrolysates (DCGHs) in vivo and their potential regulatory mechanisms. The systolic blood pressure (SBP) of spontaneously hypertensive rats (SHRs) was significantly reduced (10.30%) by the long-term intragastric administration of DCGHs (high doses). Also, there was drastic inhibition of angiotensin-I-converting enzyme (ACE) activity in the lung, kidney, and heart tissues by 24.53, 22.28, and 12.93%, respectively. It could regulate the blood pressure by adjusting the balance between endothelium-derived vasoconstrictor factors and endothelium-derived relaxing factors. Meanwhile, DCGHs enhanced the phagocytosis of mononuclear macrophages, cellular immunity, and humoral immunity of ICR mice by increasing the phagocytic index of mononuclear macrophages (23.71%), ear swelling degree (44.82%), and antibody levels (52.32%). Moreover, it stimulated the release of immunoactive substances (e.g., lysozyme, interferon-γ, immunoglobulin G, and complement 3). Consequently, DCGHs could suitably be used in the formulation of novel functional foods with antihypertensive and immunomodulatory properties.

Investigation of Chlorella pyrenoidosa Protein as a Source of Novel Angiotensin I-Converting Enzyme (ACE) and Dipeptidyl Peptidase-IV (DPP-IV) Inhibitory Peptides

Chlorella pyrenoidosa (C. pyrenoidosa) is a microalgae species with a remarkably high protein content that may potentially become a source of hypotensive and hypoglycemic peptides. In this study, C. pyrenoidosa proteins were extracted and hydrolyzed overnight with pepsin and trypsin with final degrees of hydrolysis of 18.7% and 35.5%, respectively. By LC-MS/MS, 47 valid peptides were identified in the peptic hydrolysate (CP) and 66 in the tryptic one (CT). At the concentration of 1.0 mg/mL, CP and CT hydrolysates inhibit in vitro the angiotensin-converting enzyme (ACE) activity by 84.2 ± 0.37% and 78.6 ± 1.7%, respectively, whereas, tested at cellular level at the concentration of 5.0 mg/mL, they reduce the ACE activity by 61.5 ± 7.7% and 69.9 ± 0.8%, respectively. At the concentration of 5.0 mg/mL, they decrease in vitro the DPP-IV activity by 63.7% and 69.6% and in Caco-2 cells by 38.4% and 42.5%, respectively. Short peptides (≤10 amino acids) were selected for investigating the potential interaction with ACE and DPP-IV by using molecular modeling approaches and four peptides were predicted to block both enzymes. Finally, the stability of these peptides was investigated against gastrointestinal digestion.

Purification and the secondary structure of a novel angiotensin I-converting enzyme (ACE) inhibitory peptide from the alcalase hydrolysate of seahorse protein

Bioactive peptides with blood pressure-lowering functions have received increasing attention. In recent years, many ACE-inhibiting peptides have been widely purified from various food-derived proteins and have received considerable interest owing to their potential role in cardiovascular diseases and in the reduction of side effects. In this study, we hydrolyzed a three-spot seahorse (Hippocampus trimaculatus Leach) protein by alcalase to obtain a hydrolysate containing angiotensin I-converting enzyme (ACE) inhibitory peptide. Then, the hydrolysate was fractionated by dialysis, Sephadex G-25 gel filtration chromatography, and reverse-phase high performance liquid chromatography. After consecutive purification, a potent ACE-inhibiting peptide composed of 8 amino acids (Pro-Ala-Gly-Pro-Arg-Gly-Pro-Ala; MW: 721.39 Da; IC₅₀ value: 7.90 μM) was successfully isolated from three-spot seahorse protein. For the first time, a novel ACE-inhibiting peptide (PAGPRGPA) was isolated from the seahorse. Circular dichroism (CD) analyses suggested that the secondary structure of the purified peptide was mainly composed of random coil. Therefore, the peptide from seahorse protein may be used as a favorable ingredient in nutraceuticals, medicines, and functional foods against antihypertensive and related diseases.

Purification of Pseudomonas sp. proteases through aqueous biphasic systems as an alternative source to obtain bioactive protein hydrolysates

Aqueous biphasic systems (ABSs) are an interesting alternative for separating industrial enzymes due to easy scale-up and low operational cost. The proteases of Pseudomonas sp. M211 were purified through ABS platforms formed by polyethylene glycol (PEG) and citrate buffer salt. Two experimental designs 2³  + 4 were performed to evaluate the following parameters: molar mass of PEG (M_PEG ), concentration of PEG (C_PEG ), concentration of citrate buffer (C_Cit ), and pH. The partition coefficient (K), activity yield (Y), and purification factor (PF) were the responses analyzed. The best purification performance was obtained with the system composed of M_PEG  = 10,000 g/mol, C_PEG  = 22 wt%, C_Cit  = 12 wt%, pH = 8.0; the responses obtained were K = 4.9, Y = 84.5%, PF = 15.1, and tie-line length = 52.74%. The purified proteases of Pseudomonas sp. (PPP) were used to obtain hydrolysates of Lupinus mutabilis (Peruvian lupin cultivar) seed protein in comparison with the commercial protease Alcalase® 2.4L. A strong correlation between hydrolysis degree and radical scavenging activity was observed, and the highest antioxidant activity was obtained with Alcalase® (1.40 and 3.47 μmol Trolox equivalent/mg protein, for 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and oxygen radical absorbance capacity, respectively) compared with PPP (0.55 and 1.03 μmol Trolox/mg protein). Nevertheless, the IC₅₀ values were lower than those often observed for antioxidant hydrolysates from plant proteins. PEG/citrate buffer system is valuable to purify Pseudomonas proteases from the fermented broth, and the purified protease could be promising to produce antioxidant protein hydrolysates.

Purification of Angiotensin-I-Converting Enzyme Inhibitory Peptides Derived from Camellia oleifera Abel Seed Meal Hydrolysate

China is a large country that produces Camellia oleifera Abel seed meal (COASM), a by-product of tea-seed oil, which is only used as an organic fertilizer, resulting in a serious waste of high-quality resources. The preparation of the ACE inhibitory peptide from COASM and the study of its functional properties are of practical importance in improving the comprehensive utilization of COASM. Our manuscript presents an optimized preparation of ACE inhibitory peptides with alkaline protease and enzyme kinetics parameters. Ultrafiltration, gel chromatography, and RP-HPLC purification were conducted for ACE inhibitory peptides, and peptide molecular weight distribution and amino acid composition were analyzed in the enzymolysis liquid. The following were the conditions of the optimized enzymatic hydrolysis to obtain ACE inhibitory peptides from COASM: 15 times of hydrolysis in distilled water for 3.5 h at 50°C, pH = 8.5, substrate concentration of 17 mg/g, and addition of 6% (w/w) alkaline protease. Under this condition, the peptides produced exhibited an ACE inhibition rate of 79.24%, and the reaction kinetics parameters are as follows: Km = 0.152 mg/mL and Vmax = 0.130 mg/mL·min. The majority of ACE inhibitory peptides from COASM have molecular weight below 1 kDa, and a high ACE inhibitory rate was achieved after dextran gel chromatography separation and purification (whose IC50 was 0.678 mg/mL). The hydrophobic amino acid content in this fraction reached 51.21%.

Peptides derived from lupin proteins confer potent protection against oxidative stress

BACKGROUND

Lupin seeds are rich in proteins, which are utilized in the food industry. There is an increased interest in lupin research due to its association with health-related benefits, such as reduction of hypertension and hyperglycemia. However, studies on the peptides derived from lupin proteins are rare.

RESULTS

Lupin protein hydrolysates (LPHs) were prepared by proteolysis using alcalase, trypsin and pepsin, respectively. All the hydrolysates demonstrated higher antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities compared to lupin proteins. The hydrolysates were fractionated into three fractions based on molecular weight (MW), and the peptides with MW < 3 kDa (LPH3) had the highest antioxidant and ACE inhibitory activities compared to other fractions. Cell model study revealed that LPH3 fraction had the highest protection against the generation of reactive oxygen species in HepG2 cells, which was associated with increased activities of superoxide dismutase and glutathione peroxidase through upregulation of SOD1, GPX1, GCLM, SLC7A11 and SRXN1 expression.

CONCLUSIONS

The analysis of amino acid composition indicated that the peptides were characterized with high content of hydrophobic amino acids, which may be responsible for the greatest antioxidant activity. This study highlights the promising potential of lupin peptides as a functional ingredient in healthy foods. © 2018 Society of Chemical Industry.

First Food-Derived Peptide Inhibitor of the Protein-Protein Interaction between Gain-of-Function PCSK9D374Y and the Low-Density Lipoprotein Receptor

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is involved in cholesterol homeostasis, because it induces the low-density lipoprotein receptor (LDLR) degradation. This protein may carry some positive or negative mutations: PCSK9^D374Y is one of the most dangerous gain-of-function mutations. This paper reports the identification of the first food-derived peptide able to inhibit the protein-protein interaction (PPI) between PCSK9^D374Y and LDLR. In fact, T9 (GQEQSHQDEGVIVR), an absorbable peptide deriving from lupin β-conglutin, is able to impair the PPI between PCSK9^D374Y and the LDLR, with an IC₅₀ value equal to 285.6 ± 2.46 μM. The consequence of this inhibition is an increase of the protein level of the LDLR located on hepatic cell membranes up to 74.3 ± 4.4% and the restoration of the functional capability of HepG2 cells to uptake extracellular low-density lipoprotein up to 83.1 ± 1.6%. Finally, the putative binding mode of T9 to the LDLR binding site located on PCSK9^D374Y was postulated by in silico tools.

Plant Seed Proteins: Chemistry, Technology and Applications

This review deals with the significance of plant seed proteins. Plant seed proteins are known to provide various beneficial activities like antimicrobial, antihypertensive, antiviral and antioxidant. They are essential source of amino acids; act as a source of nutrition booster. Present review elaborates on extraction of proteins and hydrolysis with their advantages and disadvantages, their nutritional property, health benefits and challenges associated with the peptides.

Reevaluating nutrition as a risk factor for cardio-metabolic diseases

Introduction:

The consumption of saturated fats is considered a risk factor for cardiovascular diseases.

Objective:

Review published papers on the role of macro-nutrient intake in cardiovascular risk.

Results:

Recent reports from the PURE study and several previous meta-analyses, show that the consumption of total saturated and unsaturated fat is not associated with risk of acute myocardial infarction or mortality due to cardiovascular disease. High carbohydrate intake was associated with the highest risk of total and cardiovascular mortality, while total fat consumption or of its different types was associated with a lower risk of mortality. A high consumption of fruits, vegetables and legumes was associated with lower risk of total mortality and non-cardiovascular mortality. The consumption of 100 g of legumes, two or three times a week, ameliorated deficiencies of the nutrients contained in these foods and was associated with a reduction in the risk of developing chronic non-communicable diseases.

Conclusion:

A healthy diet should be balanced and varied, be composed of a proportion of complex carbohydrates rich in fibber between 50-55% of the daily energy consumed, of saturated and unsaturated fat (25-30%), animal and vegetable protein (including legumes) between 15-25%, vitamins, minerals and water. These nutrients are abundantly present in fruits, vegetables, cereals, legumes, milk and its derivatives, eggs and meats, so public policies should promote the availability and access to these nutrients within primary prevention programs to reduce the growing prevalence of cardio-metabolic diseases.

Bioactive Potential of Andean Fruits, Seeds, and Tubers

The Andes is considered the longest continental mountain range in the world. It covers 7000km long and about 200-700km wide and an average height of about 4000m. Very unique plant species are endemic of this area including fruits (e.g., lucuma, cherimoya, sweet pepino, sauco), roots and tubers (potatoes, sweet potatoes, yacón, chicuru, mashua, olluco, etc.), and seeds (quinoa, amaranth, tarwi, etc.). These crops have been used for centuries by the native population and relatively recently have gained the world attention due to the wide range of nutrients and/or phytochemicals they possess. In this chapter, main Andean fruits, seeds, and roots and tubers have been selected and detailed nutritional and functional information is provided. In addition, traditional and current uses are provided and their bioactive potential is reported based on published scientific literature.

Separation and Characterization of Antioxidative and Angiotensin Converting Enzyme Inhibitory Peptide from Jellyfish Gonad Hydrolysate

The gonad of jellyfish (RhopilemaesculentumKishinouye), containing high protein content with a rich amino acid composition, is suitable for the preparation of bioactive peptides. Jellyfish gonad was hydrolysed with neutral protease to obtain jellyfish gonad protein hydrolysate (JGPH), which was then purified sequentially by ultrafiltration, gel filtration chromatography, and RP-HPLC. The peptides were characterized with HPLC-MS/MS. One peptide with amino acid sequence Ser-Tyr (SY) was identified and synthesized, which showed good ACE inhibitory and antioxidant activity. The IC50 of this peptide on DPPH, ·OH, super oxygen anion scavenging activities, and ACE inhibitory activity are 84.623 μM, 1177.632 μM, 456.663 μM, and 1164.179 μM, respectively. The anchor in the binding site of SY and ACE C-domain (ACE-C) was obtained by molecular simulations. The results showed that the dipeptide purified from jellyfish gonad protein hydrolysates can be used as functional food material and is helpful in the study of antioxidant and inhibition of ACE.

New ACE-Inhibitory Peptides from Hemp Seed (Cannabis sativa L.) Proteins

A hemp seed protein isolate, prepared from defatted hemp seed meals by alkaline solubilization/acid precipitation, was subjected to extensive chemical hydrolysis under acid conditions (6 M HCl). The resulting hydrolysate was fractionated by semipreparative RP-HPLC, and the purified fractions were tested as inhibitors of angiotensin converting enzyme (ACE). Mono- and bidimensional NMR experiments and LC-MS analyses led to the identification of four potentially bioactive peptides, i.e. GVLY, IEE, LGV, and RVR. They were prepared by solid-phase synthesis, and tested for ACE-inhibitory activity. The IC₅₀ values were GVLY 16 ± 1.5 μM, LGV 145 ± 13 μM, and RVR 526 ± 33 μM, confirming that hemp seed may be a valuable source of hypotensive peptides.

Proteomics for exploiting diversity of lupin seed storage proteins and their use as nutraceuticals for health and welfare

Lupins have a variety of both traditional and modern uses. In the last decade, reports assessing the benefits of lupin seed proteins have proliferated and, nowadays, the pharmaceutical industry is interested in lupin proteins for human health. Modern genomics and proteomics have hugely contributed to describing the diversity of lupin storage genes and, above all, proteins. Most of these studies have been centered on few edible lupin species. However, Lupinus genus comprises hundreds of species spread throughout the Old and New Worlds, and these resources have been scarcely explored and exploited. We present here a detailed review of the literature on the potential of lupin seed proteins as nutraceuticals, and the use of -omic tools to analyze seed storage polypeptides in main edible lupins and their diversity at the Lupinus inter- and intra-species level. In this sense, proteomics, more than any other, has been a key approach. Proteomics has shown that lupin seed protein diversity, where post-translational modifications yield a large number of peptide variants with a potential concern in bioactivity, goes far beyond gene diversity. The future extended use of second and third generation proteomics should definitely help to go deeper into coverage and characterization of lupin seed proteome.

BIOLOGICAL SIGNIFICANCE

Some important topics concerning storage proteins from lupin seeds are presented and analyzed in an integrated way in this review. Proteomic approaches have been essential in characterizing lupin seed protein diversity, which goes far beyond gene diversity since the protein level adds to the latter differential proteolytic cleavage of conglutin pro-proteins and a diverse array of glycosylation forms and sites. Proteomics has also proved helpful for screening and studying Lupinus germplasm with the future aim of exploiting and improving food production, quality, and nutritional values.

Coupling of ultrafiltration and enzymatic hydrolysis aiming at valorizing shrimp wastewater

The objective of this work was to obtain a protein hydrolysate from the wastewater generated during shrimp cooking, by coupling ultrafiltration and enzymatic hydrolysis processes. Initially, the effluent was concentrated by ultrafiltration, reaching a protein concentration factor of 3.2. The concentrated effluent was then enzymatically hydrolyzed, aiming at obtaining peptides with antioxidant capacity. The effects of some process variables--temperature (55-75 °C), pH (7-9) and enzyme/substrate (E/S) ratio (0.1-2.5%)--on the degree of hydrolysis and the antioxidant capacity were evaluated. The increase in temperature and pH resulted in lower degree of hydrolysis and higher antioxidant capacity. The conditions selected as the most suitable were: temperature of 75 °C, pH of 9.0 and E/S ratio of 0.1%. The hydrolysates produced at these conditions were also evaluated for total amino acid content and electrophoretic profile, showing a suitable amount of essential amino acids that covers the recommended daily needs.

Two Peptides from Soy β-Conglycinin Induce a Hypocholesterolemic Effect in HepG2 Cells by a Statin-Like Mechanism: Comparative in Vitro and in Silico Modeling Studies

Two peptides from soybean β-conglycinin, i.e., YVVNPDNDEN (peptide 2) and YVVNPDNNEN (peptide 3), are known to be absorbed by human enterocytes. The former is a fragment of LRVPAGTTFYVVNPDNDENLRMIA (peptide 1), previously shown to increase the low-density lipoprotein (LDL) uptake and degradation in hepatocytes. Research carried out in silico on their interactions with the catalytic site of 3-hydroxy-3-methylglutaryl CoA reductase (HMGCoAR) demonstrated that they behave as competitive inhibitors of HMGCoAR activity with a statin-like mechanism, confirmed by direct inhibition experiments. Research in HepG2 cells aimed at investigating the effects of these peptides on cholesterol metabolism showed that compared to mock treatment peptide 2 at 350 μM up-regulates the mature SREBP2 protein level by 134.0 ± 10.5%, increases the LDLR protein level by 152.0 ± 20.0%, and enhances the HMGCoAR protein production by 171 ± 29.9%, whereas peptide 3 up-regulates the mature SREBP2 protein level by 158.0 ± 9.2%, increases the LDL level 164.0 ± 17.9%, and induces a HMGCoAR protein increase by 170 ± 50.0%.