Identification of ACE-inhibitory peptides from Phaseolus vulgaris after in vitro gastrointestinal digestion

Alpha-cadinol as a potential ACE-inhibitory volatile compound identified from Phaseolus vulgaris L. through in vitro and in silico analysis

Hypertension is a major risk factor of cardiovascular diseases, which is mainly caused due to over activation of renin-angiotensin system. The angiotensin converting enzyme (ACE), which is involved in formation of angiotensin II from angiotensin I, causes the blood vessels to constrict, in turn leading to hypertension. The current study was initiated to understand the role of bioactive volatile compounds from Phaseolus vulgaris L. (common bean), in ACE enzyme inhibition. Beans aqueous extract (BAE) showed maximum ACE inhibition of 88.4 ± 0.8% in comparison to other commonly consumed vegetables like spinach and garlic. The head space gas chromatography-mass spectrometry analysis showed the presence of a number of terpenes and terpenoids, which were present prominently in BAE. In silico molecular docking studies indicated that among the other volatile compounds, alpha-cadinol (-7.27 kcal/mol) and ar-tumerone (-6.44 kcal/mol) have the maximum binding affinity with the active site of ACE, as compared to that of captopril (-6.41 kcal/mol). The molecular dynamic simulation in biological environment, showed that alpha-cadinol forms a stable complex with ACE, with average binding energy of -42 kJ/mol. The ACE:alpha-cadinol complex was found to be stable mainly due to the hydrophobic interactions of alpha-cadinol with active site residues (Tyr523 and Phe457) of ACE. The in silico drug-likeness analysis showed that alpha-cadinol is appropriate for human system with no predicted hepatotoxicity or mutagenicity (AMES toxicity).Communicated by Ramaswamy H. Sarma.

Anti-Inflammatory, ACE Inhibitory, Antioxidative Activities and Release of Novel Antihypertensive and Antioxidative Peptides from Whey Protein Hydrolysate with Molecular Interactions

OBJECTIVE

The aim of the study was to evaluate the whey protein hydrolysate with bio-functional attributes viz. antioxidative, anti-inflammatory and ACE inhibition efficacy and release of bioactive peptides with antioxidative and ACE-inhibitory activity by employing Pepsin.

METHOD

The antioxidant, Anti-inflammatory, ACE inhibitory and proteolytic activities of the whey protein hydrolysates were studied followed by SDS-PAGE analysis and IEF. Anti-inflammatory activity of whey protein hydrolysate was also studied on RAW 264.7 cell line. The separation of the bioactive peptides from whey protein hydrolysate was achieved by RP-HPLC. The purified bioactive peptides were identified and characterized using RPLC/MS.

RESULTS

WPC (Whey protein concentrate) hydrolysate with pepsin showed proteolytic activity ranging between 14.46 and 18.87 mg/ml. Using the ABTS assay, the highest antioxidative activity was observed in 10 kDa retentate (84.50%) and 3 kDa retentate (85.96%), followed by the highest proteolytic activity (13.83 mg/ml) and ACE inhibitory activity (58.37%) in a 5% WPC solution at 65 °C after 8 h of pepsin hydrolysis. When the protein hydrolysate concentration was low, the production of proinflammatory cytokines by lipopolysaccharide-treated murine macrophages (RAW 264.7) was reduced. SDS-PAGE results exhibited very little protein bands when comparing with WPC hydrolysates to insoluble WPC. There were no protein spots on 2 D gel electrophoresis and "in-solution trypsin digestion" technique have been utilized to digest protein samples directly from WPC hydrolysates. Novel antioxidative peptides and ACE inhibitory peptides were also observed by comparing two databases, i.e., BIOPEP and AHTPDB respectively. The peptide sequences used in this study were found to have excellent potential to be used as inhibitors of hACE as all of them were able to show substantial interactions against the enzyme's active site.

CONCLUSIONS

The antihypertensive and antioxidative peptides from whey protein hydrolysates may be beneficial for the future development of physiologically active functional foods. Further, in vivo investigations are required to establish the health claim for each individual bioactive peptide from whey protein hydrolysate.

Supplemental data for this article is available online at.

Release of Bioactive Peptides from Erythrina edulis (Chachafruto) Proteins under Simulated Gastrointestinal Digestion

The estimated and concerning rise in world population over the next few years and the consequent increase in food demand will lead to a deterioration in global food security. To avoid or reduce this world crisis, informed and empowered consumers are turning to sustainable and nutrient-rich foods that substitute animal products, also reducing their associated environmental impact. Moreover, due to the demonstrated influence of diet on the risk of high incidence and mortality of noncommunicable diseases, the current established food pattern is focused on the consumption of foods that have functionality for health. Among these new foods, traditional and underutilized plants are gaining interest as alternative protein sources providing nutritional and biological properties. In this work, the potential of Erythrina edulis (chachafruto) proteins as a source of multifunctional peptides after transit through the gastrointestinal tract has been demonstrated, with antioxidant and immunostimulating effects in both biochemical assays and cell culture. While low molecular weight peptides released during the digestive process were found to be responsible for protection against oxidative stress mediated by their radical scavenging activity, high molecular weight peptides exerted immunostimulating effects by upregulation of immunoresponse-associated biomarkers. The findings of this study support the promising role of chachafruto proteins as a new antioxidant and immunostimulatory ingredient for functional foods and nutraceuticals.

A peptide fraction from hardened common beans (Phaseolus vulgaris) induces endothelium-dependent antihypertensive and renal effects in rats

Beans reached the research spotlight as a source of bioactive compounds capable of modulating different functions. Recently, we reported antioxidant and oxidonitrergic effect of a low molecular weight peptide fraction (<3 kDa) from hardened bean (Phaseolus vulgaris) in vitro and ex vivo, which necessitate further in vivo assessments. This work aimed to evaluate the hypotensive effect and the involved physiological mechanisms of the hardened common bean peptide (Phaseolus vulgaris) in normotensive (Wistar) and hypertensive (SHR) animals. Bean flour was combined with a solution containing acetonitrile, water and formic acid (25: 24: 1). Protein extract (PV3) was fractioned (3 kDa membrane). We assessed PV3 effects on renal function and hemodynamics of wistar (WT-normotensive) and spontaneously hypertensive rats (SHR) and measured systemic arterial pressure and flow in aortic and renal beds. The potential endothelial and oxidonitrergic involvements were tested in isolated renal artery rings. As results, we found that PV3: I) decreased food consumption in SHR, increased water intake and urinary volume in WT, increased glomerular filtration rate in WT and SHR, caused natriuresis in SHR; II) caused NO- and endothelium-dependent vasorelaxation in renal artery rings; III) reduced arterial pressure and resistance in aortic and renal vascular beds; IV) caused antihypertensive effects in a dose-dependent manner. Current findings support PV3 as a source of bioactive peptides and raise the potential of composing nutraceutical formulations to treat renal and cardiovascular diseases.

Current trends and perspectives on bioaccessibility and bioavailability of food bioactive peptides: in vitro and ex vivo studies

The bioaccessibility and bioavailability of food-derived bioactive compounds are important issues when assessing their in vivo physiological health-promoting effects. Food components such as proteins and peptides are exposed to different proteases and peptidases during gastrointestinal digestion and absorption. Different in vitro approaches have therefore been developed to evaluate the bioaccessibility and stability of bioactive peptides. The static simulated gastrointestinal digestion model (SGD) was widely reported to assess the bioaccessibility of bioactive peptides. On the other hand, although the dynamic SGD model may better simulate human digestion, it has rarely been explored in bioaccessibility studies of food bioactive peptides due to its high cost and lack of standardization. For bioavailability studies, the Caco-2 cell monolayer model has been used extensively for the assessment of food bioactive peptides. In fact, very few reports using alternative methods for determining transepithelial transport of bioactive peptides have been employed. In this sense, ex vivo tissue-based models such as the Ussing chamber and the everted sac gut have been used. Current evidence supports the fact that using SGD with cell-based models for evaluating the bioaccessibility, absorption, and bioavailability of food-derived bioactive peptides, is the most commonly used approach. Nevertheless, SGD with ex vivo tissue-based models such as the everted sac, remains to be further explored because it seems to be the model that better mimics the physiological process - it is also fast and inexpensive, and several compounds may be tested simultaneously. In the present review, we discuss information available on the different in vitro approaches for the determination of bioaccessibility and bioavailability of food-derived bioactive peptides with special emphasis on ex vivo tissue-based models such as the everted sac and the Ussing chamber models. © 2022 Society of Chemical Industry.

Characterization of Angiotensin I-Converting Enzyme (ACE) inhibitory peptides produced in fermented camel milk (Indian breed) by Lactobacillus acidophilus NCDC-15

Fermented camel milk provides many health benefits like antidiabetic activity, anti-hypertensive activity etc. Fermented camel milk contains IPP or VPP rich ACE inhibitory peptides. The aim of this study was to spot the novel Angiotensin I-Converting Enzyme inhibitory peptides liberated by the potent proteolytic Lactobacillus acidophilus NCDC-15 from camel milk (Indian breed). NCDC-15 had exhibited maximum PepX activity (0.655) and ACE-inhibitory activity (78.33%) at 12 and 48 h of incubation at 37 °C respectively. Proteolytic activity was measured using o-phthaldialdehyde method and observed maximum (0.976 OD) at 2% of inoculation for 12 h of incubation at 37 °C. Water soluble extracts derived from fermented camel milk were ultrafiltered through 3 kDa, 5 kDa and 10 kDa membrane filters from which 3 kDa permeates (48.01% peptides production & 49.46% ACE-inhibition) and 10 kDa permeates (55.04% peptides production & 42.40% ACE-inhibition) had shown maximum peptides production and ACE-inhibitory activity. Overall, 24 peptides were identified from the samples of 3 kDa permeates [6 fractions (K1, L1, M1, N1, O1 and P1)] and 10 permeates [5 fractions (S, T, U, V and W)]. Novel peptide (AIGPVADLHI) was matched with k-casein in AHTPDB database and other peptides were also found matched with α and β-caseins of camel milk.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05357-9.

Significance of whey protein hydrolysate on anti-oxidative, ACE-inhibitory and anti-inflammatory activities and release of peptides with biofunctionality: an in vitro and in silico approach

The study aimed to investigate potent antioxidant activities (ABTS assay, Hydroxyl free radical scavenging assay, and Superoxide free radical assay), ACE inhibitory activity, and anti-inflammatory activity in the WPC (whey protein concentrate) hydrolysate using Alcalase. The hydrolysis conditions (addition rate and incubation times) for peptide synthesis were also optimized using proteolytic activity. The generation of proinflammatory cytokines by lipopolysaccharide-treated murine macrophages was reduced when the protein hydrolysate concentration was low. In comparison to unhydrolyzed WPC, SDS-PAGE examination revealed no protein bands in WPC hydrolysates. Two-Dimensional (2D) gel electrophoresis did not show any protein spots. Using the 'In-solution trypsin digestion' approach, the trypsin digested protein samples were put into RPLC/MS for amino acid sequencing. Peptides were also identified using RPLC/MS on fractions of 3 and 10 kDa permeates and retentates. The MASCOT database was used to look up the raw masses of LC/MS. By comparing hydrolyzed whey protein to the BLASTp (NCBI), PIR, BIOPEP, and AHTPDB databases, novel antioxidative and ACE inhibitory peptides were reported.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05282-3.

Peptidomic profiling of fermented goat milk: considering the fermentation-time dependent proteolysis by Lactobacillus and characterization of novel peptides with Antioxidative activity

In this study, antioxidant activities were evaluated for goat milk fermented with Lactobacillus helveticus MTCC 5463. The fermentation conditions (inoculation rate and incubation time) were optimized by estimating proteolytic action of Lactobacillus. SDS-PAGE and 2D gel electrophoresis were carried out for identification of molecular weight and purification of identified peptides. 3 and 10 kDa peptides fractions were obtained through ultrafiltration and also by using RP-HPLC. Then, spots from 2D and fractions from RP-HPLC were also evaluated in RP-LC/MS for identification and characterization of peptides. Identified peptides were matched with online database of goat milk i.e. BLASTp (NCBI) and Protein information resource database (PIR) and subsequently, antioxidant activity of these peptides were also confirmed with BIOPEP database. However, antioxidative peptides from fermented goat milk with Lactobacillus helveticus MTCC 5463 could be produced in developing functional goat milk yoghurt.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-021-05243-w.

Application of a Combined Peptidomics and In Silico Approach for the Identification of Novel Dipeptidyl Peptidase-IV-Inhibitory Peptides in In Vitro Digested Pinto Bean Protein Extract

The conventional approach in bioactive peptides discovery, which includes extensive bioassay-guided fractionation and purification processes, is tedious, time-consuming and not always successful. The recently developed bioinformatics-driven in silico approach is rapid and cost-effective; however, it lacks an actual physiological significance. In this study a new integrated peptidomics and in silico method, which combines the advantages of the conventional and in silico approaches by using the pool of peptides identified in a food hydrolysate as the starting point for subsequent application of selected bioinformatics tools, has been developed. Pinto bean protein extract was in vitro digested and peptides were identified by peptidomics. The pool of obtained peptides was screened by in silico analysis and structure–activity relationship modelling. Three peptides (SIPR, SAPI and FVPH) were selected as potential inhibitors of the dipeptidyl-peptidase-IV (DPP-IV) enzyme by this integrated approach. In vitro bioactivity assay showed that all three peptides were able to inhibit DPP-IV with the tetra-peptide SAPI showing the highest activity (IC50 = 57.7 μmol/L). Indeed, a new possible characteristic of peptides (i.e., the presence of an S residue at the N-terminus) able to inhibit DPP-IV was proposed.

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

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

Oxidonitrergic and antioxidant effects of a low molecular weight peptide fraction from hardened bean (Phaseolus vulgaris) on endothelium

About 3000 tons of beans are not used in human food due to hardening. Several studies on bean-derived bioactive peptides have shown potential to treat some diseases, including those relying on oxidative dysfunctions. We assessed the effects of peptides extracted from hardened bean Phaseolus vulgaris (PV) on reactive oxygen species (ROS) and nitric oxide (NO) production, cytotoxic and cytoprotective effects in endothelial cells, and oxidonitrergic-dependent vasodilating effects. Extract was composed by peptide fraction <3 kDa (PV3) from hardened common bean residue. PV3 sequences were obtained and analyzed with bioinformatics. Human umbilical vein endothelial cells were treated with 10, 20, 30, and 250 µg/mL PV3. Oxidative stress was provoked by 3% H₂O₂. Cytotoxicity and cytoprotective effects were evaluated by MTT assay, whereas, ROS and NO were quantified using DHE and DAF-FM fluorescent probes by confocal microscopy. NO- and endothelium-dependent vasodilating effects of PV3 were assessed in isolated aortic rings. We found 35 peptides with an average mass of 1.14 kDa. There were no cell deaths with 10 and 20 μg/mL PV3. PV3 at 30 μg/mL increased cell viability, while cytotoxicity was observed only with 250 μg/mL PV3. PV3 at 10 μg/mL was able to protect cells from oxidative stress. PV3 also increased NO release without causing cell death. It also reduced relative ROS production induced by H₂O₂. PV3 vasodilating effects relied on endothelium-dependent NO release. PV3 obtained from low-commercial-value bean displays little cytotoxicity and exerts antioxidant effects, whereas it increases endothelial NO release.

Therapeutic opportunities of edible antiviral plants for COVID-19

The pandemic of Serious Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2) that produces corona virus disease (COVID-19) has challenged the entire mankind by rapidly spreading globally in 210 countries affecting over 25 million people and about 1 million deaths worldwide. It continues to spread, afflicting the health system globally. So far there is no remedy for the ailment and the available antiviral regimens have been unsatisfactory for the clinical outcomes and the mode of treatment has been mainly supportive for the prevention of COVID-19-induced morbidity and mortality. From the time immortal the traditional plant-based ethno-medicines have provided the leads for the treatment of infectious diseases. Phytopharmaceuticals have provided potential and less toxic antiviral drugs as compared to conventional modern therapeutics which are associated with severe toxicities. The ethnopharmacological knowledge about plants has provided food supplements and nutraceuticals as a promise for prevention and treatment of the current pandemic. In this review article, we have attempted to comprehend the information about the edible medicinal plant materials with potential antiviral activity specifically against RNA virus which additionally possess property to improve immunity along with external and internal respiration and exhibit anti-inflammatory properties for the prevention and treatment of the disease. This will open an arena for the development of novel nutraceutical herbal formulations as an alternative therapy that can be used for the prevention and treatment of COVID-19.

Bioaccessibility and In Vitro Intestinal Permeability of a Recombinant Lectin from Tepary Bean (Phaseolus acutifolius) Using the Everted Intestine Assay

Tepary bean (Phaseolus acutifolius) lectins exhibit differential in vitro and in vivo biological effects, but their gastrointestinal interactions and digestion have not yet been assessed. This work aimed to evaluate the changes of a recombinant Tepary bean lectin (rTBL-1) through an in vitro and ex vivo gastrointestinal process. A polyclonal antibody was developed to selectively detect rTBL-1 by Western blot (WB) and immunohistochemical analysis. Everted gut sac viability was confirmed until 60 min, where protein bioaccessibility, apparent permeability coefficient, and efflux ratio showed rTBL-1 partial digestion and absorption. Immunoblot assays suggested rTBL-1 internalization, since the lectin was detected in the digestible fraction. The immunohistochemical assay detected rTBL-1 presence at the apical side of the small intestine, potentially due to the interaction with the intestinal cell membrane. The in silico interactions between rTBL-1 and some saccharides or derivatives showed high binding affinity to sialic acid (-6.70 kcal/mol) and N-acetylglucosamine (-6.10 kcal/mol). The ultra-high-performance liquid chromatography-electron spray ionization-quantitative time-of-flight coupled to mass spectrometry (UHPLC-ESI-QTOF/MS) analysis showed rTBL-1 presence in the gastric content and the non-digestible fraction after intestinal simulation conditions. The results indicated that rTBL-1 partially resisted the digestive conditions and interacted with the intestinal membrane, whereas its digestion allowed the absorption or internalization of the protein or the derivative peptides. Further purification of digestion samples should be conducted to identify intact rTBL-1 protein and digested peptides to assess their physiological effects.

Bovine whey peptides transit the intestinal barrier to reduce oxidative stress in muscle cells

Health benefits are routinely attributed to whey proteins, their hydrolysates and peptides based on in vitro chemical and cellular assays. The objective of this study was to track the fate of whey proteins through the upper gastrointestinal tract, their uptake across the intestinal barrier and then assess the physiological impact to downstream target cells. Simulated gastrointestinal digestion (SGID) released a selection of whey peptides some of which were transported across a Caco-2/HT-29 intestinal barrier, inhibited free radical formation in muscle and liver cells. In addition, SGID of β-lactoglobulin resulted in the highest concentration of free amino acids (176 nM) arriving on the basolateral side of the co-culture with notable levels of branched chain and sulphur-containing amino acids. In vitro results indicate that consumption of whey proteins will deliver bioactive peptides to target cells.

Release of the Antihypertensive Tripeptides Valine-Proline-Proline and Isoleucine-Proline-Proline from Bovine Milk Caseins during in Vitro Gastrointestinal Digestion

The aim of this study was to identify and quantify the release of antihypertensive tripeptides valine-proline-proline (VPP) and isoleucine-proline-proline (IPP) during in vitro oro-gastro-intestinal (OGI) digestion of bovine skimmed milk. The experimental approach combined the recently developed harmonized static in vitro digestion (IVD) model and targeted mass spectrometry to monitor peptide generation. We first demonstrated that VPP and IPP are released from bovine milk proteins during in vitro OGI digestion at final concentrations of 354.3 ± 29.8 and 973.8 ± 155.7 μg/L, respectively. In silico analysis of cleavage sites and mass spectrometry revealed that tetrapeptides VPPF, IPPL, and IPPK are precursors of VPP and IPP. The release of other ACE-inhibitory peptides, such as FVAP, VAP, AW, and VY, was demonstrated, and their fate and the time course were investigated. This research underlines the suitability of an IVD system to study the release of short bioactive peptides during OGI transit.

Dietary peptides from the non-digestible fraction of Phaseolus vulgaris L. decrease angiotensin II-dependent proliferation in HCT116 human colorectal cancer cells through the blockade of the renin–angiotensin system

Peptides in common beans reduced angiotensin II-dependent proliferation in HCT116 colon cancer cells.