Effect of amaranth proteins on the RAS system. In vitro, in vivo and ex vivo assays

Dynamic digestion of a high protein beverage based on amaranth: Structural changes and antihypertensive activity

An amaranth beverage (AB) was subjected to a simulated process of dynamic gastrointestinal digestion DIDGI®, a simple two-compartment in vitro dynamic gastrointestinal digestion system. The structural changes caused to the proteins during digestion and the digesta inhibitory capacity of the angiotensin converting enzyme (ACE) were investigated. In gastric compartment the degree of hydrolysis (DH) was 14.7 ± 1.5 % and in the intestinal compartment, proteins were digests in a greater extent (DH = 60.6 ± 8.4 %). Protein aggregation was detected during the gastric phase. The final digesta obtained both at the gastric and intestinal level, showed ACE inhibitory capacity (IC50 80 ± 10 and 140 ± 20 μg/mL, respectively). Purified fractions from these digesta showed even greater inhibitory capacity, being eluted 2 (E2) the most active fraction (IC50 60 ± 10 μg/mL). Twenty-six peptide sequences were identified. Six of them, with potential antihypertensive capacity, belong to A. hypochondriacus, 3 agglutinins and 3 encrypted sequences in the 11S globulin. Results obtained provide new and useful information on peptides released from the digestion of an amaranth based beverage and its ACE bioactivity.

Potential antihypertensive activity of novel peptides from green basil leaves

Hypertension is among the risk factors of death globally. Novel antihypertensive peptides are alternative choices of antihypertensive assistance. This study aimed to discover novel antihypertensive peptides from green basil leaves. Two bioactive peptides with high angiotensin-converting enzyme inhibition (Asp-Leu-Ser-Ser-Ala-Pro; peptide 1) and antioxidant (Asp-Ser-Val-Ser-Ala-Ser-Pro; peptide 2) activities were gavaged to male Wistar rats induced with NG-nitro-l-arginine methyl-ester (L-NAME). L-NAME-treated rats (HT) had decreased body weights and levels of nitrite and nitrate, which are metabolites of nitric oxide. The levels of their glucose and liver function indicators increased as compared to normal rats. HT rats receiving antihypertensive drugs (HTD) showed higher low-density lipoprotein and low-density lipoprotein/high-density lipoprotein levels than HT rats. Peptide 1 seems to benefit the rat lipid profiles, liver functions, antioxidant, nitrite, nitrate, and angiotensin II peptide levels but not peptide 2. In conclusion, our findings indicate the antihypertensive potential related to vasodilation of peptides from green basil leaves.

Amaranth proteins and peptides: Biological properties and food uses

Amaranthus grains have attracted great attention due to its attractive health benefits. The grains have processing properties (e.g., starch related properties) similar to those of common cereals. Amaranth grains are gluten free and protein is a significant component of these grains. Proteins of the grains have been used in various food applications such as formulations of edible films and emulsions for controlled release of bioactive compounds. The proteins have been hydrolyzed using different enzymes to produce peptides and hydrolysates, which showed a range of biological functions including anti-hypertensive and antioxidant activities among others. They have been formulated into staple foods including breads and pastas for improved nutritional quality. This review summarizes the recent advances of the last 5 years in understanding the biological functions and food applications of proteins, protein hydrolysates and peptides from the grains of different Amaranthus species. Limitations in the studies summarized are critically discussed with an aim to improve the efficiency in amaranth grain protein and peptide research.

Bioactive protein hydrolysates obtained from amaranth by fermentation with lactic acid bacteria and Bacillus species

Protein hydrolysates are a promising source of bioactive peptides. One strategy by which they can be obtained is fermentation. This method uses the proteolytic system of microorganisms to hydrolyze the parental protein. Fermentation is a little-explored method for obtaining protein hydrolysates from amaranth. Different strains of lactic acid bacteria (LAB) and Bacillus species isolated from goat milk, broccoli, aguamiel, and amaranth flour were used in this work. First, the total protein degradation (%TPD) of amaranth demonstrated by the strains was determined. The results ranged from 0 to 95.95%, the strains that produced a higher %TPD were selected. These strains were identified by molecular biology and were found to correspond to the genera Enterococcus, Lactobacillus, Bacillus, and Leuconostoc. Fermentation was carried out with amaranth flour and the selected strains. After this process, water/salt extracts (WSE) containing the released protein hydrolysates were obtained from amaranth doughs. The peptide concentration was measured by the OPA method. The antioxidant, antihypertensive and antimicrobial activity of the WSE was evaluated. In the FRAP test, the best WSE was LR9 with a concentration of 1.99 μMTE/L ± 0.07. In ABTS, 18C6 obtained the highest concentration with 19.18 μMTE/L ± 0.96. In the DPPH test, there was no significant difference. In terms of antihypertensive activity, inhibition percentages ranging from 0 to 80.65% were obtained. Some WSE were found to have antimicrobial properties against Salmonella enterica and Listeria monocytogenes. Fermentation of amaranth with LAB and Bacillus spp. allowed the release of protein hydrolysates with antioxidant, antihypertensive, and antimicrobial activity.

Microencapsulated bioactive peptides from brewer's spent grain promotes antihypertensive and antidiabetogenic effects on a hypertensive and insulin-resistant rat model

The effects of microcapsules containing brewer's spent grain (BSG) peptides were evaluated on a hypertensive/insulin-resistant rat model induced by a sucrose-rich diet (SRD) administration. Animals received for 100 days the control diet (CD), SRD, and CD and SRD diets supplemented with microencapsulated peptides (CD-P and SRD-P). During the experimental period, blood pressure was monitored. Glycemia, tissue glycogen content, nitric oxide, and the activity of enzymes related to hypertensive and diabetogenic mechanisms were determined. The consumption of SRD caused hypertensive and hyperglycemic effects compared to CD. However, the SRD-P group presented lower systolic pressure at the middle of ingestion, achieving similar values than the CD. The SRD-P rats decreased all enzymes' activities compared to the SRD reaching the values of CD, except for those of α-amylase in cecal content and DPP-IV in serum. It was possible to corroborate potential antihypertensive and antidiabetogenic in vivo effects of the microencapsulated BSG peptides. PRACTICAL APPLICATIONS: Brewer's spent grain (BSG) is the main waste obtained from brewing industry. Bioactive peptides obtained after an enzymatic hydrolysis of proteins with in vitro antihypertensive and antidiabetogenic activity have been described. However, to corroborate the action of these bioactive peptides, in vivo studies are necessary. In the present work, microcapsules containing bioactive peptides from BSG were administered on the rat model with induced hypertension and insulin-resistance, corroborating an in vivo antihypertensive and antidiabetogenic effects by inhibition of enzymes related with blood pressure regulation and glucose metabolism. This work demonstrated that microcapsules of BSG peptides could be included into functional foods formulations, or used as dietary supplement for improving health and the prevention of non-communicable diseases, adding value to the brewing process by-product.

Conventional and in silico approaches to select promising food-derived bioactive peptides: A review

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Seaweed and edible insects are considered new sources of bioactive peptides.

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Conventional approaches are necessary to validate the bioactivity of peptides.

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Bioinformatics tools accelerate the obtaining of bioactive peptides.

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The integrated approach is a promising strategy to obtain bioactive peptides.

The interest for food-derived bioactive peptides, either from common or unconventional sources, has increased due to their potential therapeutic effect against a wide range of diseases. The study of such bioactive peptides using conventional methods is a long journey, expensive and time-consuming. Hence, bioinformatic approaches, which can not only help to predict the formation of bioactive peptides from any known protein source, but also to analyze the protein structure/function relationship, have gained a new meaning in this scientific field. Therefore, this review aims to provides an overview of conventional characterization methods and the most recent advances in the field of in silico approaches for predicting and screening promising food-derived bioactive peptides.

Amaranth as a Source of Antihypertensive Peptides

Amaranth is an ancestral crop used by pre-Columbian cultures for 6000 to 8000 years. Its grains have a relevant chemical composition not only from a nutritional point of view but also due to the contribution of components with good techno-functional properties and important potential as bioactive compounds. Numerous studies have shown that amaranth storage proteins possess encrypted sequences that, once released, exhibit different physiological activities. One of the most studied is antihypertensive activity. This review summarizes the progress made over the last years (2008-2020) related to this topic. Studies related to inhibition of different enzymes of the Renin-Angiotensin-Aldosterone system, in particular Angiotensin Converting Enzyme (ACE) and Renin, as well as those referring to potential modulation mechanisms of tissue or local Renin-Angiotensin-Aldosterone system, are analyzed, including in silico, in vitro, in vivo, and ex vivo assays. Furthermore, the potential use of these bioactive peptides or products containing them, in the elaboration of functional food matrices is discussed. Finally, the most relevant conclusions and future requirements in research and development of food products are presented.

Antidiabetic Food-Derived Peptides for Functional Feeding: Production, Functionality and In Vivo Evidences

Bioactive peptides released from the enzymatic hydrolysis of food proteins are currently a trending topic in the scientific community. Their potential as antidiabetic agents, by regulating the glycemic index, and thus to be employed in food formulation, is one of the most important functions of these peptides. In this review, we aimed to summarize the whole process that must be considered when talking about including these molecules as a bioactive ingredient. In this regard, at first, the production, purification and identification of bioactive peptides is summed up. The detailed metabolic pathways described included carbohydrate hydrolases (glucosidase and amylase) and dipeptidyl-peptidase IV inhibition, due to their importance in the food-derived peptides research field. Then, their characterization, concerning bioavailability in vitro and in situ, stability and functionality in food matrices, and ultimately, the in vivo evidence (from invertebrate animals to humans), was described. The future applicability that these molecules have due to their biological potential as functional ingredients makes them an important field of research, which could help the world population avoid suffering from several diseases, such as diabetes.

Data set on effect of amaranth proteins on the RAS system. In vitro, in vivo and ex vivo assays

Data set presented in this article is related to the research paper entitled "Effect of amaranth proteins on the RAS system. In vitro, in vivo and ex vivo assays", available in Food Chemistry [1]. In this article, we evaluated the effect on systolic blood pressure of spontaneously hypertensive rats (SHR) of different samples with amaranth proteins/peptides. The effect of these samples on RAS system was evaluated using in vitro and ex vivo assays. The concentration of renin and angiotensin converting enzyme (ACE) was evaluated using two commercial ELISA kits. Renin concentration was estimated through a direct immunoassay and ACE concentration with an immunoassay based on a competitive inhibition. In addition, the ACE inhibitory activity in plasma was evaluated using a spectrophotometric assay according to [2]. Ex vivo experiments were done with thoracic aorta extracted during the surgical procedure employed to obtain blood samples according to [3]. Data presented in this article recollect a very extensive work on how can be affect the RAS system in SHR model using amaranth protein/peptides as potential antihypertensive samples. These data could be useful to design novel functional foods for hypertensive individuals.