Characterization of Chenopodin Isoforms from Quinoa Seeds and Assessment of Their Potential Anti-Inflammatory Activity in Caco-2 Cells

Nutritional and functional perspectives of pseudocereals

An increase in the consumption of carbohydrate-rich cereals over past few decades has led to increased metabolic disorders in population. This nutritional imbalance in diets may be corrected by substituting cereal grains with pseudocereals that are richer in high-quality proteins, dietary fibers, unsaturated fats, and bioactive compounds (e.g., polyphenols and phytosterols) as compared to cereal grains. These nutrients have been associated with numerous health benefits, such as hypolipidemic, anti-inflammatory, anti-hypertensive, anti-cancer, and hepatoprotective properties, and benefits against obesity and diabetes. In this review, the nutritional composition and health benefits of quinoa, amaranth, and buckwheat are compared against wheat, maize, and rice. Subsequently, the processing treatments applied to quinoa, amaranth, and buckwheat and their applications into food products are discussed. This is relevant since there is substantial market potential for both pseudocereals and functional foods formulated with pseudocereals. Despite clear benefits, the current progress is slowed down by the fact that the cultivation of these pseudocereals is limited to its native regions. Therefore, to meet the global needs, it is imperative to support worldwide cultivation of these nutrient-rich pseudocereals.

A quinoa peptide protects impaired mucus barriers in colitis mice by inhibiting NF-κB-TRPV1 signaling and regulating the gut microbiota

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions that lead to the disruption of the colonic mucus barrier. Quinoa has a well-balanced profile of essential amino acids and exhibits excellent anti-inflammatory effects. We recently explored the beneficial effects and relevant mechanisms of a novel quinoa peptide TPGAFF on impaired mucus barriers in mice with chemically induced colitis. Our findings demonstrated that TPGAFF, administered in low and high doses for 28 days, effectively attenuated the pathological phenotype and reduced intestinal permeability in colitis mice. TPGAFF demonstrated its protective abilities by restoring the impaired mucus barrier, inhibiting the activation of inflammatory signaling and reducing inflammatory cytokine levels. Moreover, TPGAFF positively influenced the composition of the gut microbiota by reducing inflammation-related microbes. Additionally, TPGAFF inhibited the activation of TRPV1 nociceptor and decreased the levels of neuropeptides. Conclusively, our results indicated that oral administration of TPGAFF may be an optional approach for the treatment of mucus barrier damage.

Antibacterial and Antiviral Properties of Chenopodin-Derived Synthetic Peptides

Antimicrobial peptides have been developed based on plant-derived molecular scaffolds for the treatment of infectious diseases. Chenopodin is an abundant seed storage protein in quinoa, an Andean plant with high nutritional and therapeutic properties. Here, we used computer- and physicochemical-based strategies and designed four peptides derived from the primary structure of Chenopodin. Two peptides reproduce natural fragments of 14 amino acids from Chenopodin, named Chen1 and Chen2, and two engineered peptides of the same length were designed based on the Chen1 sequence. The two amino acids of Chen1 containing amide side chains were replaced by arginine (ChenR) or tryptophan (ChenW) to generate engineered cationic and hydrophobic peptides. The evaluation of these 14-mer peptides on Staphylococcus aureus and Escherichia coli showed that Chen1 does not have antibacterial activity up to 512 µM against these strains, while other peptides exhibited antibacterial effects at lower concentrations. The chemical substitutions of glutamine and asparagine by amino acids with cationic or aromatic side chains significantly favoured their antibacterial effects. These peptides did not show significant hemolytic activity. The fluorescence microscopy analysis highlighted the membranolytic nature of Chenopodin-derived peptides. Using molecular dynamic simulations, we found that a pore is formed when multiple peptides are assembled in the membrane. Whereas, some of them form secondary structures when interacting with the membrane, allowing water translocations during the simulations. Finally, Chen2 and ChenR significantly reduced SARS-CoV-2 infection. These findings demonstrate that Chenopodin is a highly useful template for the design, engineering, and manufacturing of non-toxic, antibacterial, and antiviral peptides.

Quinoa protein and its hydrolysate ameliorated DSS-induced colitis in mice by modulating intestinal microbiota and inhibiting inflammatory response

The objective of this study was to investigate the protective effects of quinoa protein (QPro) and its derived peptides (QPep) in dextran sulfate sodium (DSS)-induced colitis in mice. The results demonstrated that oral administration of QPro and QPep significantly alleviated colitis symptoms, including diarrhea, abdominal pain, bloody stools, weight loss, as well as reduced colonic shortening, inflammatory factor release, and intestinal barrier injury. Short-chain fatty acids (SCFAs) production rose as QPro and QPep modulated the composition of the intestinal microbiota. Western blotting results revealed that QPro and QPep also suppressed TLR4 levels and inhibited IκB-α and NF-κB phosphorylation in colon tissue, implying that the TLR4/IκB-α/NF-κB signaling pathway may be involved in the amelioration of QPro and QPep in DSS-induced colitis. These results indicate the potential of quinoa protein and its hydrolysate to serve as bioactive components in functional diets for intestinal health and to significantly lower intestinal inflammation.

Glycine-rich peptides from fermented Chenopodium formosanum sprout as an antioxidant to modulate the oxidative stress

Rhizopus oligosporus was utilized in the solid-state fermentation of Chenopodiumformosanumsprouts (FCS) in a bioreactor. Subsequently, the antioxidant activity of food proteins derived from FCS was investigated. Results showed that glycine-rich peptide (GGGGGKP, G-rich peptide), identified from the <2 kDa FCS proteins, had antioxidant values. According to SwissADME, AllerTOP, ToxinPred, and BIOPEP-UWM analyses, G-rich peptide was identified as safe, non-toxic, and non-allergenic. Afterward, the peptide was examined using in silico and in vitro studies to evaluate its potential alleviating oxidative stress caused by particulate matter. This study proposed plausible mechanisms that involve the binding of G-rich peptide which inhibited phosphorylation of the v-rel avian reticuloendotheliosis viral oncogene homologA(RELA) subunit onNF-κB pathway. The inhibition then resulted in down regulation of NF-κB transcription and genetic expression of inflammatory responses. These findings suggested that G-rich peptide from FCS proteins can potentially alleviate oxidative stress.

Nutrient composition, functional activity and industrial applications of quinoa (Chenopodium quinoa Willd.)

Quinoa is one of the gluten-free crops that has attracted considerable interest. Quinoa contains functional ingredients such as bioactive peptides, polysaccharides, saponins, polyphenols, flavonoids and other compounds. It is very important to determine efficient methods to identify such functional ingredients, and to explain their possible health benefits in humans. In this review, the chemical structure and biological activity mechanisms of quinoa nutrient composition have been elaborated. In addition, the development of quinoa-based functional foods and feed is emerging, providing a reference for the development of functional products with quinoa as an ingredient that are beneficial to health. The active ingredients in quinoa have different health effects including antioxidant, antidiabetic, antihypertensive, anti-inflammatory, and anti-obesity activities. Further exploration is also needed to improve the application of quinoa within the functional food industry, and in the areas of feed, medicine and cosmetics.

Recent advances in physiochemical changes, nutritional value, bioactivities, and food applications of germinated quinoa: A comprehensive review

The production and consumption of functional foods has become an essential food industry trend. Due to its high nutritional content, quinoa is regarded as a super pseudocereal for the development of nutritious foods. However, the presence of antinutritional factors and quinoa's distinctive grassy flavor limit its food applications. Due to its benefits in enhancing the nutritional bioavailability and organoleptic quality of quinoa, germination has garnered significant interest. To date, there is no systematic review of quinoa germination and the health benefits of germinated quinoa. This review details the nutritional components and bioactivities of germinated quinoa, as well as the potential mechanisms for the accumulation of bioactive compounds during the germination process. Additionally, evidence supporting the health benefits of germinated quinoa, the current status of related product development, and perspectives for future research are presented. Thus, our research is likely to provide theoretical support for the use of germinated quinoa resources.

Nutritional Evaluation of Quinoa Genetic Resources Growing in the Climatic Conditions of Central Europe

Quinoa displays huge genetic variability and adaptability to distinct climatic conditions. Quinoa seeds are a good source of nutrients; however, the overall nutritional composition and nutrient content is influenced by numerous factors. This study focused on the nutritional and morphologic evaluation of various quinoa genotypes grown in the Czech Republic. Significant differences between years were observed for morphological traits (plant height, inflorescence length, weight of thousand seeds). The weather conditions in the year 2018 were favorable for all the morphological traits. The protein content of quinoa accessions ranged between 13.44 and 20.01% and it was positively correlated to mauritianin. Total phenolic content varied greatly from year to year, while the antioxidant activity remained relatively stable. The most abundant phenolic compounds were the flavonoids miquelianin, rutin, and isoquercetin. Isoquercetin, quercetin, and N-feruoloyl octopamine showed the highest stability under variable weather conditions in the analyzed years. A total of six compounds were detected and quantified in quinoa for the first time. Most varieties performed well under Central European conditions and can be considered a good source of nutrients and bioactive compounds. These data can be used as a source of information for plant breeders aiming to improve the quality traits of quinoa.

A Proteomics Data Mining Strategy for the Identification of Quinoa Grain Proteins with Potential Immunonutritional Bioactivities

Quinoa proteins are attracting global interest for their wide amino acid profile and as a promising source for the development of biomedical treatments, including those against immune-mediated diseases. However, information about the bioactivity of quinoa proteins is scarce. In this study, a quinoa grain proteome map obtained by label-free mass spectrometry-based shotgun proteomics was investigated for the identification of quinoa grain proteins with potential immunonutritional bioactivities, including those related to cancer. After carefully examining the sequence similarities of the 1211 identified quinoa grain proteins against already described bioactive proteins from other plant organisms, 71, 48, and 3 of them were classified as antimicrobial peptides (AMPs), oxidative stress induced peptides (OSIPs), and serine-type protease inhibitors (STPIs), respectively, suggesting their potential as immunomodulatory, anti-inflammatory, and anticancer agents. In addition, data interpretation using Venn diagrams, heat maps, and scatterplots revealed proteome similarities and differences with respect to the AMPs, OSIPs, and STPIs, and the most relevant bioactive proteins in the predominant commercial quinoa grains (i.e., black, red, white (from Peru), and royal (white from Bolivia)). The presented proteomics data mining strategy allows easy screening for potentially relevant quinoa grain proteins and commercial classes for immunonutrition, as a basis for future bioactivity testing.

Medicinal Plants in Peru as a Source of Immunomodulatory Drugs Potentially Useful Against COVID-19

The current COVID-19 pandemic, characterized by a highly contagious severe acute respiratory syndrome, led us to look for medicinal plants as an alternative to obtain new drugs, especially those with immunomodulatory abilities, capable of acting against the pulmonary infection caused by coronavirus 2 (SARS-CoV-2). Despite medical advances with COVID-19 drugs and vaccines, plant-based compounds could provide an array of suitable candidates to test against this virus, or at the very least, to alleviate some symptoms. Therefore, this review explores some plants widely used in Peru that show immunomodulatory properties or, even more, contain phytoconstituents potentially useful to prevent or alleviate the COVID-19 infection. More interestingly, the present review highlights relevant information from those plants to support the development of new drugs to boost the immune system. We used three criteria to choose nine vegetal species, and a descriptive search was then conducted from 1978 to 2021 on different databases, using keywords focused on the immune system that included information such as pharmacological properties, phytochemical, botanical, ethnobotanical uses, and some clinical trials. From these literature data, our results displayed considerable immunomodulation activity along with anti-inflammatory, antiviral, antioxidant, and antitumoral activities. Noticeably, these pharmacological activities are related with a wide variety of bioactive phytoconstituents (mixtures or isolated compounds) which may be beneficial in modulating the overt inflammatory response in severe COVID-19. Further scientific research on the pharmacological activities and clinical utilization of these potential plants are warranted.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43450-023-00367-w.

An overview of the nutritional profile, processing technologies, and health benefits of quinoa with an emphasis on impacts of processing

Consumers are becoming increasingly conscious of adopting a healthy lifestyle and demanding food with high nutritional values. Quinoa (Chenopodium quinoa Willd.) has attracted considerable attention and is consumed worldwide in the form of a variety of whole and processed products owing to its excellent nutritional features, including richness in micronutrients and bioactive phytochemicals, well-balanced amino acids composition, and gluten-free properties. Recent studies have indicated that the diverse utilization and final product quality of this pseudo-grain are closely related to the processing technologies used, which can result in variations in nutritional profiles and health benefits. This review comprehensively summarizes the nutritional properties, processing technologies, and potential health benefits of quinoa, suggesting that quinoa plays a promising role in enhancing the nutrition of processed food. In particular, the effects of different processing technologies on the nutritional profile and health benefits of quinoa are highlighted, which can provide a foundation for the updating and upgrading of the quinoa processing industry. It further discusses the present quinoa-based food products containing quinoa as partial or whole substitute for traditional grains.

Recent updates on lentil and quinoa protein-based dairy protein alternatives: Nutrition, technologies, and challenges

Due to its high nutritional value and increasing consumption trends, plant-based proteins were used in a variety of dietary products, either in their entirety or as partial substitutions. There is indeed a growing need to produce plant-based proteins as alternatives to dairy-based proteins that have good functional properties, high nutritional values, and high protein digestibility. Among the plant-based proteins, both lentil and quinoa proteins received a lot of attention in recent years as dairy-based protein alternatives. To ensure plant-based proteins a success in food applications, food industries and researchers need to have a comprehensive scientific understanding of these proteins. The demand for proteins is highly dependent on several factors, mainly functional properties, nutritional values, and protein digestibility. Fermentation and protein complexation are recognised to be suitable techniques in enhancing the functional properties, nutritional values, and protein digestibility of these plant-based proteins, making them potential alternatives for dairy-based proteins.

Thermal Shift Assay as a Tool to Evaluate the Release of Breakdown Peptides from Cowpea β-Vignin during Seed Germination

The present work aimed to characterize the molecular relationships between structure and function of the seed storage protein β-vignin, the vicilin storage protein of cowpea (Vigna unguiculata, l. Walp) seeds. The molecular characterization of β-vignin was carried out firstly by assessing its thermal stability, under different conditions of pH and ionic strength, by thermal shift assay (TSA) using SYPRO Orange fluorescent dye. Secondly, its aggregation propensity was evaluated using a combination of chromatographic and electrophoretic techniques. Two forms of β-vignin were considered: the native form purified from mature quiescent seeds, and a stable breakdown intermediate of 27 kDa produced while seeds germinate. TSA is a useful tool for determining and following over time the structural changes that occur to the protein during germination. The main result was the molecular characterization of the 27 kDa intermediate breakdown polypeptide, which, to the best of our knowledge, has never been described before. β-vignin seems to retain its trimeric conformation despite the evident degradation of its polypeptides.

Transcriptional Regulation of Quinoa Seed Quality: Identification of Novel Candidate Genetic Markers for Increased Protein Content

Quinoa (Chenopodium quinoa Willd.) is a crop that has great potential for increased cultivation in diverse climate regions. The seed protein quality obtained from this crop is high concerning the requirements to meet human nutritional needs, but the seed protein content is relatively low if compared to crops such as grain legumes. Increased seed protein content is desirable for increasing the economic viability of this crop in order for it to be used as a protein crop. In this study, we characterized three genotypes of quinoa with different levels of seed protein content. By performing RNA sequencing of developing seeds, we determined the genotype differences in gene expression and identified genetic polymorphisms that could be associated with increased protein content. Storage nutrient analyses of seeds of three quinoa genotypes (Titicaca, Pasankalla, and Regalona) from different ecoregions grown under controlled climate conditions showed that Pasankalla had the highest protein content (20%) and the lowest starch content (46%). Our seed transcriptome analyses revealed highly differentially expressed transcripts (DETs) in Pasankalla as compared to the other genotypes. These DETs encoded functions in sugar transport, starch and protein synthesis, genes regulating embryo size, and seed transcription factors. We selected 60 genes that encode functions in the central carbon metabolism and transcription factors as potential targets for the development of high-precision markers. Genetic polymorphisms, such as single nucleotide polymorphisms (SNPs) and base insertions and deletions (InDels), were found in 19 of the 60 selected genes, which can be further evaluated for the development of genetic markers for high seed protein content in quinoa. Increased cultivation of quinoa can contribute to a more diversified agriculture and support the plant protein diet shift. The identification of quinoa genotypes with contrasting seed quality can help establish a model system that can be used for the identification of precise breeding targets to improve the seed quality of quinoa. The data presented in this study based on nutrient and transcriptome analyses contribute to an enhanced understanding of the genetic regulation of seed quality traits in quinoa and suggest high-precision candidate markers for such traits.

Exploration on bioactive properties of quinoa protein hydrolysate and peptides: a review

Quinoa is an excellent source of nutritional and bioactive components. Protein is considered a key nutritional advantage of quinoa grain, and many studies have highlighted the nutritional and physicochemical properties of quinoa protein. In addition, quinoa protein is a good precursor of bioactive peptides. This review focused on the biological properties of quinoa protein hydrolysate and peptides, and gave a summary of the preparation and functional test of quinoa protein hydrolysate and peptides. A combination of milling fractionation and solvent extraction is recommended for the efficient production of quinoa protein. The biological functionalities of quinoa protein hydrolysate, including antidiabetic, antihypertensive, anti-inflammatory, antioxidant activities, and so on, have been extensively investigated based on in vitro studies and limited animal models. Additionally, bioinformatics analysis, including proteolysis simulation, virtual screening, and molecular docking, provides an alternative or assistive approach for exploring the potential bioactivity of quinoa protein and peptides. Nevertheless, further research is required for industrial production of bioactive quinoa peptides, verification of health benefits in humans, and mechanism interpretation of observed effects.

Characterization and differentiation of quinoa seed proteomes by label-free mass spectrometry-based shotgun proteomics

Quinoa seed proteins are of prime importance in human nutrition and in plant breeding for cultivar identification and improvement. In this study, proteins from seeds of black, red, white quinoa from Peru and white quinoa from Bolivia (also known as royal) were extracted, digested and analyzed by nano-liquid chromatography coupled to Orbitrap tandem mass spectrometry (LC-MS/MS). The raw mass spectra data were processed for identification and label-free quantification (LFQ) using MaxQuant/Andromeda against a specific quinoa database from The National Center for Biotechnology Information (NCBI). In total, 1,211 quinoa proteins (85 were uncharacterized) were identified. Inspection and visualization using Venn diagrams, heat maps and Gene Ontology (GO) graphs revealed proteome similarities and differences between the four varieties. The presented data provides the most comprehensive experimental quinoa seed proteome map existing to date in the literature, as a starting point for more specific characterization and nutritional studies of quinoa and quinoa-containing foodstuff.

Bioactivities of Pseudocereal Fractionated Seed Proteins and Derived Peptides Relevant for Maintaining Human Well-Being

Food proteins and peptides are able to exert a variety of well-known bioactivities, some of which are related to well-being and disease prevention in humans and animals. Currently, an active trend in research focuses on chronic inflammation and oxidative stress, delineating their major pathogenetic role in age-related diseases and in some forms of cancer. The present study aims to investigate the potential effects of pseudocereal proteins and their derived peptides on chronic inflammation and oxidative stress. After purification and attribution to protein classes according to classic Osborne's classification, the immune-modulating, antioxidant, and trypsin inhibitor activities of proteins from quinoa (Chenopodium quinoa Willd.), amaranth (Amaranthus retroflexus L.), and buckwheat (Fagopyrum esculentum Moench) seeds have been assessed in vitro. The peptides generated by simulated gastro-intestinal digestion of each fraction have been also investigated for the selected bioactivities. None of the proteins or peptides elicited inflammation in Caco-2 cells; furthermore, all protein fractions showed different degrees of protection of cells from IL-1β-induced inflammation. Immune-modulating and antioxidant activities were, in general, higher for the albumin fraction. Overall, seed proteins can express these bioactivities mainly after hydrolysis. On the contrary, higher trypsin inhibitor activity was expressed by globulins in their intact form. These findings lay the foundations for the exploitation of these pseudocereal seeds as source of anti-inflammatory molecules.

Chromatography-Independent Fractionation and Newly Identified Molecular Features of the Adzuki Bean (Vigna angularis Willd.) β-vignin Protein

Adzuki seed β-vignin, a vicilin-like globulin, has proven to exert various health-promoting biological activities, notably in cardiovascular health. A simple scalable enrichment procedure of this protein for further nutritional and functional studies is crucial. In this study, a simplified chromatography-independent protein fractionation procedure has been optimized and described. The electrophoretic analysis showed a high degree of homogeneity of β-vignin isolate. Furthermore, the molecular features of the purified protein were investigated. The adzuki bean β-vignin was found to have a native size of 146 kDa, and the molecular weight determined was consistent with a trimeric structure. These were identified in two main polypeptide chains (masses of 56-54 kDa) that are glycosylated polypeptides with metal binding capacity, and one minor polypeptide chain with a mass 37 kDa, wherein these features are absent. The in vitro analysis showed a high degree of digestibility of the protein (92%) and potential anti-inflammatory capacity. The results lay the basis not only for further investigation of the health-promoting properties of the adzuki bean β-vignin protein, but also for a possible application as nutraceutical molecule.

Differential Impact of Salinity Stress on Seeds Minerals, Storage Proteins, Fatty Acids, and Squalene Composition of New Quinoa Genotype, Grown in Hyper-Arid Desert Environments

The effects of climate change and soil salinization on dryland ecosystems are already widespread, and ensuring food security is a crucial challenge. In this article, we demonstrate changes in growth performance and seed quality of a new high-yielding quinoa genotype (Q5) exposed to sodium chloride (NaCl), sodium sulfate (Na₂SO₄), and mixed salts (NaCl + Na₂SO₄). Differential responses to salt stress in growth performance, seed yield, and seed quality were identified. High salinity (mixed Na₂SO₄ + NaCl) reduces plant height by ∼30%, shoot and root dry weights by ∼29%, head panicle length and panicle weight by 36-43%, and seed yield by 37%, compared with control conditions. However, the 1,000-seed weight changes insignificantly under salinity. High content of essential minerals, such as Fe, Zn, and Ca in quinoa Q5 seeds produced under salinity, gives the Q5 genotype a remarkable advantage for human consumption. Biomarkers detected in our studies show that the content of most essential amino acids is unchanged under salinity. The content of amino acids Pro, Gly, and Ile positively correlates with Na⁺ concentration in soil and seeds, whereas the content of squalene and most fatty acids negatively correlates. Variation in squalene content under increasing salinity is most likely due to toxic effects of sodium and chlorine ions as a result of the decrease in membrane permeability for ion movement as a protective reaction to an increase in the sodium ion concentration. Low squalene accumulation might also occur to redirect the NADPH cofactor to enhance the biosynthesis of proline in response to salinity, as both syntheses (squalene and proline) require NADPH. This evidence can potentially be used by the food and pharmaceutical industries in the development of new food and health products.