Potential antitumor properties of a protein isolate obtained from the seeds of Amaranthus mantegazzianus

The effect of environmental stressors on the anticancer potential of Amaranthus hypochondriacus aqueous extracts and fractions

Some Amaranthus species have been shown to have pharmacological properties such as activity against cancer, and it is also used as a traditional herbal medicine in many rural parts of the world. The (3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide assay was used as a screening tool to determine the approximate cell viability inhibitory concentrations of methanol and aqueous crude extracts of Amaranthus spp. The extracts were screened using small-cell lung cancer (H69V), hepatocellular carcinoma (HepG2/C3A) and non-cancerous kidney cells (Vero) cell lines. Viability was assessed following exposure to a series of concentrations of each extract and A. hypochondriacus showed cytotoxicity of 70.55 µg/mL against H69V with a Si index of 1.8. The fractionated aqueous extract of 40 °C-treated A. hypochondriacus under well-watered conditions had a higher viability inhibition on H69V and Vero cell lines compared to the A. caudatus, A. cruentus and A. spinosus crude extracts. In conclusion, A. hypochondriacus could serve as a potential source of anticancer phytoconstituents for drug development.

Plant-derived rennet: research progress, novel strategies for their isolation, identification, mechanism, bioactive peptide generation, and application in cheese manufacturing

Rennet, an aspartate protease found in the stomach of unweaned calves, effectively cuts the peptide bond between Phe105-Met106 in κ-casein, hydrolyzing the casein micelles to coagulate the milk and is a crucial additive in cheese production. Rennet is one of the most used enzymes of animal origin in cheese making. However, using rennet al.one is insufficient to meet the increasing demand for cheese production worldwide. Numerous studies have shown that plant rennet can be an alternative to bovine rennet and exhibit a good renneting effect. Therefore, it is crucial and urgent to find a reliable plant rennet. Based on our team's research on rennet enzymes of plant origin, such as from Dregea sinensis Hemsl. and Moringa oleifer Lam., for more than ten years, this paper reviews the relevant literature on rennet sources, isolation, identification, rennet mechanism, functional active peptide screening, and application in cheese production. In addition, it proposes the various techniques for targeted isolation and identification of rennet and efficient screening of functionally active peptides, which show excellent prospects for development.

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.

The nutraceutical properties and health benefits of pseudocereals: a comprehensive treatise

This review article depicts the possible replacement of staple cereal sources with some pseudocereals like Chia, Quinoa, Buckwheat, and Amaranth, which not only provide recommended daily allowance of all nutrients but also help to reduce the chances of many non-communicable infections owing to the presence of several bioactive compounds. These pseudocereals are neglected plant seeds and should be added in our routine diet. Besides, they can serve as nutraceuticals in combating various diseases by improving the health status of the consumers. The bioactive compounds like rutin, quercetin, peptide chains, angiotensin I, and many other antioxidants present in these plant seeds help to reduce the oxidative stress in the body which leads toward better health of the consumers. All these pseudocereals have high quantity of soluble fiber which helps to regulate bowel movement, control hypercholesterolemia (presence of high plasma cholesterol levels), hypertension (high blood pressure), and cardiovascular diseases. The ultimate result of consumption of pseudocereals either as a whole or in combination with true cereals as staple food may help to retain the integrity of the human body which increases the life expectancy by slowing down the aging process.

Nutritional Quality of Four Novel Porridge Products Blended with Edible Cricket (Scapsipedus icipe) Meal for Food

Currently, no data exist on the utilization of the newly described cricket species (Scapsipedus icipe) meal as additive in food products, though they have high protein (57%) with 88% total digestibility as well as a variety of essential amino acids. This article presents the first report on the effects of processing techniques and the inclusion of cricket meal (CM) on the nutrient and antinutrient properties of four porridge products compared to a popularly consumed commercial porridge flour (CPF). Porridge enriched with CM had significantly higher protein (2-folds), crude fat (3.4–4-folds), and energy (1.1–1.2-folds) levels than the CPF. Fermented cereal porridge fortified with CM had all three types of omega-3 fatty acids compared to the others. The vitamin content across the different porridge products varied considerably. Germinated cereal porridge with CM had significantly higher iron content (19.5 mg/100 g). Zinc levels ranged from 3.1–3.7 mg/100 g across the various treatments. Total flavonoid content varied significantly in the different porridge products. The phytic acid degradation in germinated and fermented porridge products with CM was 67% and 33%, respectively. Thus, the fortification of porridge products with cricket and indigenous vegetable grain powder could be considered an appropriate preventive approach against malnutrition and to reduce incidences in many low-and middle-income countries.

ACC deaminase-producing Ensifer adhaerens KS23 enhances proximate nutrient of Pisum sativum L. cultivated in high altitude

A phytohormone producing, N2-fixing and 1-aminocyclopropane-1-carboxylate (ACC) deaminase synthesizing bacterium Ensifer adhaerens KS23 effectively increased the yield and nutritional contents of Pisum sativum var. Arkel. The isolate KS23 showed positive ACC deaminase activity with 174.2 (nmol of α-ketobutyrate/g-1 biomass½ h-1) a 9.7-fold increase in glutathione S-transferase activity. The proximate analysis exhibited an increased yield of protein (21.45%), carbohydrate (38.90%), sulphur (29.94%) starch (27.52%), total ash (35.57%), fat content (27.5%), nitrogen (24.06%) and hydrogen (17.91%) in treated seeds of P. sativum as compared to untreated crop seeds in field trials at Srikot village, Srinagar-246,174 (Garhwal) India. The most desirable essential and non-essential amino-acids content was also enhanced simultaneously by E. adhaerens KS23 as compared to non-treated crop seeds. This study revealed the enhancement of various nutritional contents resulting in quality improvement and an increase in growth productivity of pea. This study provides an encouraging result that may benefit the marginal income of farmers belonging mainly to hilly regions who are dependent on traditional methods of farming and thus improving their economy.

A N-acetyl-D-galactosamine-binding lectin from Amaranthus gangeticus seeds inhibits biofilm formation and Ehrlich ascites carcinoma cell growth in vivo in mice

AGL, a 15-kDa lectin from Amaranthus gangeticus seeds was isolated using ion-exchange and gel filtration chromatography. AGL contained 8.55% of neutral sugar and became specifically inhibited by N-acetyl-D-galactosamine. Hemagglutination activity of the lectin was maximum over the pH range of 4.0-6.0 and temperatures of 30-60 °C though it lost the activity when treated with urea and EDTA. With an LC₅₀ value of 250 μg/ml, AGL showed mild toxicity against Artemia nauplii. It inhibited the growth of pathogenic bacteria like Shigella boydii, Shigella dysenteriae and Staphylococcus aureus when treated for 8 and 16 h, respectively, but lost the antibacterial activity during a 24 h treatment. AGL could not inhibit the growth of Escherichia coli and mitogenic growth (7.0-9.0%) was observed instead. AGL inhibited 37.14%, 65.71% and 82.85% of biofilm formation of Escherichia coli at the concentrations of 250, 500 and 1000 μg/ml, respectively. Marked inhibition of the proliferation of Ehrlich ascites carcinoma cells was determined when treated with various doses of AGL. AGL inhibited 65.89% and 81.25% of the in vivo growth of EAC cells in mice at the doses of 2.0 and 4.0 mg/kg/day, respectively. Significant alteration of the expression of apoptosis related genes Fas, NF-kB and MAPK were observed.

Exploring the potentials of underutilized grain amaranth (Amaranthus spp.) along the value chain for food and nutrition security: A review

The burden of malnutrition in Africa calls for deeper exploration of underutilized species which are rich in nutrients and have the potential to reduce food and nutrition insecurity. The common staple crops are not able to meet daily requirements for both macro- and micro-nutrients. In order to lessen this burden; protein, calorie and micronutrient deficiencies must be properly addressed for optimal growth and development to be attained. African indigenous underutilized vegetables can play a significant role in the food security of vulnerable groups like under-five children and women in both urban and rural settings. The potential of grain amaranth in meeting the nutrition needs of humans has remained a subject of interest in scientific research. Amaranth is considered one of the most commonly produced and consumed indigenous vegetables on the African continent with high nutritional potentials but yet to be fully exploited. This review therefore aims at discussing the current knowledge of the inherent potentials of grain amaranths, its current application in the food industry and proposes a framework for actions and partnerships required to scale up and improve amaranth value chain.

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.

PepSAVI-MS Reveals a Proline-rich Antimicrobial Peptide in Amaranthus tricolor

Traditional medicinal plants are a rich source of antimicrobials; however, the bioactive peptide constituents of most ethnobotanical species remain largely unexplored. Herein, PepSAVI-MS, a mass spectrometry-based peptidomics pipeline, was implemented for antimicrobial peptide (AMP) discovery in the medicinal plant Amaranthus tricolor. This investigation revealed a novel 1.7 kDa AMP with strong activity against Escherichia coli ATCC 25922, deemed Atr-AMP1. Initial efforts to determine the sequence of Atr-AMP1 utilized chemical derivatization and enzymatic digestion to provide information about specific residues and post-translational modifications. EThcD (electron-transfer/higher-energy collision dissociation) produced extensive backbone fragmentation and facilitated de novo sequencing, the results of which were consistent with orthogonal characterization experiments. Additionally, multistage HCD (higher-energy collisional dissociation) facilitated discrimination between isobaric leucine and isoleucine. These results revealed a positively charged proline-rich peptide present in a heterogeneous population of multiple peptidoforms, possessing several post-translational modifications including a disulfide bond, methionine oxidation, and proline hydroxylation. Additional bioactivity screening of a simplified fraction containing Atr-AMP1 revealed activity against Staphylococcus aureus LAC, demonstrating activity against both a Gram-negative and a Gram-positive bacterial species unlike many known short chain proline-rich antimicrobial peptides.

Antiproliferative Effect of Amaranth Proteins and Peptides on HT-29 Human Colon Tumor Cell Line

Antiproliferative effect of Amaranthus mantegazzianus proteins and peptides released after simulated gastrointestinal digestion (DH% 37.8 ± 3.8) was investigated on human colon cancer cell line HT-29. Inhibition of proliferation of HT-29 cells was exhibited after a 24 h treatment with different concentrations of amaranth protein isolate (API) and the peptides released after digestion (DGS), presenting IC₅₀ values of 1.35 ± 0.12 and 0.30 ± 0.07 mg soluble protein/mL, respectively. Lactate dehydrogenase assay indicated that both samples caused the loss of membrane integrity and cell lysis over HT-29 cells, and DAPI fluorescence microscopies evidenced typical apoptotic features. Moreover, Annexin V-FITC flow cytometry showed a significant increase of early apoptotic and late apoptotic/necrotic HT-29 cells compared to untreated ones, and caspase-3 assay confirmed the apoptosis induction with a 43.0 ± 10.3 and 65.8 ± 12.7% increase of caspase-3 activity produced by a 2 mg/mL treatment of API and DGS, respectively. In conclusion, amaranth peptides successfully released after simulated gastrointestinal digestion would exert a potential antiproliferative activity over HT-29 tumor cells. This effect was linked to the induction of cell necrosis and apoptosis, supporting the idea of using amaranth proteins as a potential food alternative ingredient for functional foods.

Effect of plant growth promoting Bacillus spp. on nutritional properties of Amaranthus hypochondriacus grains

Amaranth (Amaranthus hypochondriacus Linn.) is an important pseudocereal crop having important nutrients along with the indispensable amino-acids. The present study was aimed to study the effect of plant growth promoting bacilli on proximate constituents of amaranth grains, including three of the essential amino acids (methionine, lysine and, tryptophan). The combination of Bacillus pumilus and Bacillus subtilis showed a significant increase in different proximate constituents, including crude protein (22.13%), dry matter (32.25%), fat (30.77%), and carbohydrate (49.08%) in amaranth grains. Similarly, a significant increase in essential amino-acids (methionine 47.68%, lysine 59.41% and, tryptophan 38.05%) was recorded. This study suggests that the combination of Bacillus pumilus BS-27 and Bacillus subtilis BS-58 provides the natural, persistent and durable potential to enhance the nutritive value of the crop. Therefore, present study was designed to explore the enhancement of most desirable amino acid synthesis in amaranth due to application of plant growth promoting Bacillus spp.

Antioxidant Activity of Zein Hydrolysates from Zea Species and Their Cytotoxic Effects in a Hepatic Cell Culture

In recent years, food proteins with bioactivity have been studied for cancer treatment. Zein peptides have shown an important set of bioactivities. This work compares the cytotoxic activity of zein hydrolyzed, extracted from four Zea species: teosinte, native, hybrid, and transgenic (Teo, Nat, Hyb, and HT) in a hepatic cell culture. Zein fraction was extracted, quantified, and hydrolyzed. Antioxidant capacity and cytotoxicity assays were performed on HepG2 cells. The levels of expression of caspase 3, 8, and 9 were evaluated in zein-treated cell cultures. Zea parviglumis showed the highest zein content (46.0 mg/g) and antioxidant activity (673.40 TE/g) out of all native zeins. Peptides from Hyb and HT showed high antioxidant activity compared to their native counterparts (1055.45 and 724.32 TE/g, respectively). Cytotoxic activity was observed in the cell culture using peptides of the four Zea species; Teo and Nat (IC50: 1781.63 and 1546.23 ng/mL) had no significant difference between them but showed more cytotoxic activity than Hyb and HT (IC50: 1252.25 and 1155.56 ng/mL). Increased expression of caspase 3 was observed in the peptide-treated HepG2 cells (at least two-fold more with respect to the control sample). These data indicate the potential for zein peptides to prevent or treat cancer, possibly by apoptosis induction.

Antiproliferative Activity of Walnut (Juglans regia L.) Proteins and Walnut Protein Hydrolysates

Proteins from Juglans regia L. were isolated. Then, proteins were hydrolyzed with different enzymes. Antiproliferative activity of proteins and of the protein hydrolysates of J. regia L. were evaluated using the sulforhodamine B method. Glutelin and prolamin proteins presented a high antiproliferative activity against cancer cells PC-3 (prostate) and K-562 (leukemia) with values of 43.9 and 84.4 μg/mL, respectively. The highest inhibitory effect observed was 50% at 0.25 μg/mL concentration in gastrointestinal digestion with pepsin and corolase pp in a dose-dependent manner against cancer cell UACC62 (melanoma). Pepsin hydrolysate showed inhibitory effects against cancer cell UACC62 (melanoma) with a concentration of 71.0 μg/mL. The effects were studied in a dose-dependent manner. The hydrolysate obtained with neutrase enzyme presented inhibitory effects against cancer cell UACC62 (melanoma) at a concentration of 25 μg/mL. Neither proteins nor protein hydrolysates presented cytotoxicity against normal cell assay VERO (epithelial).

High Hydrostatic Pressure (HHP)-Induced Structural Modification of Patatin and Its Antioxidant Activities

Patatin represents a group of homologous primary storage proteins (with molecular weights ranging from 40 kDa to 45 kDa) found in Solanum tuberosum L. This group comprises 40% of the total soluble proteins in potato tubers. Here, patatin (40 kDa) was extracted from potato fruit juice using ammonium sulfate precipitation (ASP) and exposed to high hydrostatic pressure (HHP) treatment (250, 350, 450, and 550 MPa). We investigated the effect of HHP treatment on the structure, composition, heat profile, and antioxidant potential, observing prominent changes in HHP-induced patatin secondary structure as compared with native patatin (NP). Additionally, significant (p < 0.05) increases in β-sheet content along with decreases in α-helix content were observed following HHP treatment. Thermal changes observed by differential scanning calorimetry (DSC) also showed a similar trend following HHP treatment; however, the enthalpy of patatin was also negatively affected by pressurization, and free sulfhydryl content and surface hydrophobicity significantly increased with pressurization up to 450 MPa, although both interactions progressively decreased at 550 MPa. The observed physicochemical changes suggested conformational modifications in patatin induced by HHP treatment. Moreover, our results indicated marked enhancement of antioxidant potential, as well as iron chelation activities, in HHP-treated patatin as compared with NP. These results suggested that HHP treatment offers an effective and green process for inducing structural modifications and improving patatin functionality.

Biochemical analysis and antitumour effect of Abrus precatorius agglutinin derived peptides in Ehrlich's ascites and B16 melanoma mice tumour model

Anticancer and immunostimulatory properties of tryptic digest peptides of Abrus precatorius agglutinin protein (10kDAGP) have already been reported. Here attempt has been made to further validate anticancer properties of 10kDAGP peptides in Ehrlich's ascites carcinoma (EAC) and B16 melanoma (B16M) bearing mice models and to analyze 10kDAGP by anion exchange chromatography and RP-HPLC for obtaining the bioactive fraction from the total peptide pool. 10kDAGP treatment decreased the tumour pack volume by ∼82% for EAC and 58.8% for B16M. It also showed increase in ex vivo proliferation of splenocyte and thymocyte isolated from tumour bearing mice and increase in TNF-α and Interferon-γ in splenocyte culture supernatant. From chromatographic analysis it was found that anionic peptide fraction may be responsible for anti-proliferative activities of 10kDAGP. As most anticancer peptides are cationic in nature, further studies regarding bioactivity of anionic peptide fraction may lead to novel anticancer peptides and pathways of action.

State of knowledge on amaranth grain: a comprehensive review

Amaranth grain is a highly nutritional pseudocereal with a superior amount of proteins when compared to true cereals. It is a reasonably well-balanced food with functional properties that have been shown to provide medicinal benefits. The health benefits attributed include decreasing plasma cholesterol levels, stimulating the immune system, exerting an antitumor activity, reducing blood glucose levels and improving conditions of hypertension and anemia. In addition, it has been reported to possess anti-allergic and antioxidant activities. The present article provides a comprehensive overview of amaranth grain that focuses on recent research reporting its use in the clinical practice and its possible benefits to human health.

Amaranth lunasin-like peptide internalizes into the cell nucleus and inhibits chemical carcinogen-induced transformation of NIH-3T3 cells

Because an unbalanced diet is an important risk factor for several illnesses, interest has increased in finding novel health-promoting foods. Amaranth produces seeds that not only have substantial nutritional properties but that also contain phytochemical compounds as rutin and nicotiflorin and peptides with antihypertensive and anticarcinogenic activities. We report that a cancer-preventive peptide in amaranth has activities similar to those of soybean lunasin. The amaranth lunasin-like peptide, however, requires less time than the soybean lunasin to internalize into the nucleus of NIH-3T3 cells, and inhibits histone acetylation (H(3) and H(4) in a 70 and 77%, respectively). The amaranth lunasin-like peptide inhibited the transformation of NIH-3T3 cells to cancerous foci. The open reading frame (ORF) of amaranth lunasin corresponds to a bifunctional inhibitor/lipid-transfer protein (LTP). LTPs are a family of proteins that in plants are implicated in different functions, albeit all linked to developmental processes and biotic and abiotic stress resistance. Our results open new intriguing questions about the function of lunasin in plants and support that amaranth is a food alternative containing natural peptides with health-promoting benefits.