Variations in the polyphenol content of seeds of field grown Amaranthus genotypes

Nutritional and bioactive properties and antioxidant potential of Amaranthus tricolor, A. lividus, A viridis, and A. spinosus leafy vegetables

Climate change results in continuous warming of the planet, threatening sustainable crop production around the world. Amaranth is an abiotic stress-tolerant, climate-resilient, C4 leafy orphan vegetable that has grown rapidly with great divergence and potential usage. The C4 photosynthesis allows amaranth to be grown as a sustainable future food crop across the world. Most amaranth species grow as weeds in many parts of the world, however, a few amaranth species can be also found in cultivated form. Weed species can be used as a folk medicine to relieve pain or reduce fever thanks to their antipyretic and analgesic properties. In this study, nutritional value, bioactive pigments, bioactive compounds content, and radical scavenging potential (RSP) of four weedy and cultivated (WC) amaranth species were evaluated. The highest dry matter, carbohydrate content, ash, content of iron, copper, sodium, boron, molybdenum, zinc, β-carotene and carotenoids, vitamin C, total polyphenols (TP), RSP (DPPH), and RSP (ABTS+) was determined in Amaranthus viridis (AV). On the other hand, A. spinosus (AS) was found to have the highest content of protein, fat, dietary fiber, manganese, molybdenum, and total flavonoids (TF). In A. tricolor (AT) species the highest total chlorophyll, chlorophyll a and b, betaxanthin, betacyanin, and betalain content was determined. A. lividus (AL) was evaluated as the highest source of energy. AV and AT accessions are underutilized but promising vegetables due to their bioactive phytochemicals and antioxidants.

Plant-Based Antioxidants in Gluten-Free Bread Production: Sources, Technological and Sensory Aspects, Enhancing Strategies and Constraints

The recognized contribution of antioxidant compounds to overall health maintenance and spotted deficiencies in celiac patients' diets has driven more intensive research regarding antioxidant compounds' inclusion in gluten-free bread (GFB) production during the last decade. The presented review gathered information that provided insights into plant-based antioxidant sources which are applicable in GFB production through the resulting changes in the technological, sensory, and nutritional quality of the resulting antioxidant-enriched GFB. The influence of the bread-making process on the antioxidant compounds' content alteration and applied methods for their quantification in GFB matrices were also discussed, together with strategies for enhancing the antioxidant compounds' content, their bioaccessibility, and their bioavailability, highlighting the existing contradictions and constraints. The addition of plant-based antioxidant compounds generally improved the antioxidant content and activity of GFB, without a profound detrimental effect on its technological quality and sensory acceptability, and with the extent of the improvement being dependent on the source richness and the amount added. The determination of a pertinent amount and source of plant-based antioxidant material that will result in the production of GFB with desirable nutritional, sensory, and technological quality, as well as biological activity, remains a challenge to be combated by elucidation of the potential mechanism of action and by the standardization of quantification methods for antioxidant compounds.

Physical and Chemical Characterization and Bioavailability Evaluation In Vivo of Amaranth Protein Concentrate

Special attention is being paid to the study of amaranth proteins. They are characterized by a high biological value that significantly exceeds those of grain crops. The production of protein concentrate from amaranth flour includes preliminary enzymatic hydrolysis, extraction of the resulting mixture, protein precipitation, microfiltration, and freeze-drying. In our study, the obtained amaranth protein concentrate was limited by valine, with an amino acid score of 74%. The true digestibility of the amaranth protein concentrate determined in vivo was 97.6 ± 0.3%, which was significantly lower than that of casein (99.3 ± 0.2%). The protein digestibility-corrected amino acid score value of the concentrate was 72.2%. The obtained concentrate was a rich source of selenium, copper, magnesium, manganese, and iron. Ferulic acid was the only polyphenolic compound found in the amaranth protein concentrate, but its content was significantly greater compared to the original flour. Saponins were not removed completely during the process of obtaining the amaranth protein concentrate. We identified 15 saponins in the concentrate, mainly of the bidesmoside type, the sapogenins of which are related derivatives of oleanolic acid. Thus, the developed amaranth protein concentrate can be used as an ingredient in functional food products, with a high biological value.

Evaluation of Agricultural Traits, Phytochemical Contents, and Antioxidant Activities in the Leaves of Amaranth Accessions of Nine Species

Amaranthus species are widely cultivated as dietary crops and are promising sources of phytochemical compounds with antioxidant properties. To explore Amaranthus as a potential medical resource, 289 accessions (nine species) were cultivated, and their agricultural characteristics, total phenolic content (TPC), rutin contents, and antioxidant activities [2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)] were studied. Wide variations in agricultural traits, phytochemical contents, and antioxidant activities were observed between the accessions and across species. The effects of agricultural traits were evaluated, and the results indicated that yellow-flowered amaranth genotypes could be important because of their high values of TPC, rutin contents, DPPH, and ABTS. In addition, leaf length, days until 50% flowering, days until 50% heading and days until maturity, showed positive correlations with TPC, rutin contents, DPPH, and ABTS. The whole dataset was subjected to principal component analysis, and distinctive aggregation was observed across the Amaranthus species. In total, 289 accessions were clustered into three groups, and seven genotypes were determined as being good medical resources due to their high phytochemical content and antioxidant activities. Our findings provide important information for the development of new varieties with high phytochemical contents and high levels of antioxidant activity.

Colorant Pigments, Nutrients, Bioactive Components, and Antiradical Potential of Danta Leaves (Amaranthus lividus)

In the Indian subcontinent, danta (stems) of underutilized amaranth are used as vegetables in different culinary dishes. At the edible stage of the danta, leaves are discarded as waste in the dustbin because they are overaged. For the first time, we assessed the colorant pigments, bioactive components, nutrients, and antiradical potential (AP) of the leaves of danta to valorize the by-product (leaf) for antioxidant, nutritional, and pharmacological uses. Leaves of danta were analyzed for proximate and element compositions, colorant pigments, bioactive constituents, AP (DPPH), and AP (ABTS+). Danta leaves had satisfactory moisture, protein, carbohydrates, and dietary fiber. The chosen danta leaves contained satisfactory magnesium, iron, calcium, potassium, manganese, copper, and zinc; adequate bioactive pigments, such as betacyanins, carotenoids, betalains, β-carotene, chlorophylls, and betaxanthins; and copious bioactive ascorbic acid, polyphenols, flavonoids, and AP. The correlation coefficient indicated that bioactive phytochemicals and colorant pigments of the selected danta leaves had good AP as assessed via ABTS+ and DPPH assays. The selected danta leaves had good ROS-scavenging potential that could indicate massive possibilities for promoting the health of the nutraceutical- and antioxidant-deficit public. The findings showed that danta leaves are a beautiful by-product for contributing as an alternate origin of antioxidants, nutrients, and bioactive compounds with pharmacological use.

Characterization of Phytochemicals, Nutrients, and Antiradical Potential in Slim Amaranth

Slim amaranth (A. hybridus) having a C₄ photosynthetic pathway with diverse variability is a climate-resilient crop that tolerates abiotic stresses. Owing to the high productivity of the C₄ pathway, we have been searching for suitable accessions as preferable high-yielding antioxidant-enriched cultivars with ample bioactive compounds, or for future breeding programs to improve bioactive compounds as a source of natural antioxidants. Twelve slim amaranth accessions were tested for nutraceuticals, phytopigments, radical scavenging capacity (two different assays), vitamins, total flavonoids, and total polyphenols content. Slim amaranth leaves contained ample dietary fiber, protein, moisture, and carbohydrates. The current investigation demonstrated that there was remarkable K, Ca, Mg (8.86, 26.12, and 29.31), Fe, Mn, Cu, Zn, (1192.22, 275.42, 26.13, and 1069.93), TP, TF (201.36 and 135.70), pigments, such as chlorophyll a, ab, and b, (26.28, 38.02, and 11.72), betalains, betaxanthins, betacyanins (78.90, 39.36, 39.53,), vitamin C (1293.65), β-carotene, total carotenoids, (1242.25, 1641.07), and TA (DPPH, ABTS⁺) (27.58, 50.55) in slim amaranth leaves. The widespread variations were observed across the studied accessions. The slim amaranth accessions, AH11, AH10, and AH12, exhibited high profiles of antioxidants including high potentiality to quench radicals and can be selected as preferable high-yielding antioxidant-enriched cultivars with ample bioactive compounds. Phytopigments, flavonoids, vitamins, and phenolics of slim amaranth leaves showed intense activity of antioxidants. Slim amaranth could be a potential source of proximate phenolics, minerals, phytopigments, vitamins, and flavonoids for gaining adequate nutraceuticals, bioactive components, and potent antioxidants. Moderate yielding accessions having moderate phytochemicals can be used to develop new high-yielding antioxidant-enriched cultivars for future breeding programs to improve bioactive compounds as a source of natural antioxidants.

Phytonutrients, Colorant Pigments, Phytochemicals, and Antioxidant Potential of Orphan Leafy Amaranthus Species

The underutilized Amaranthus leafy vegetables are a unique basis of pigments such as β-cyanins, β-xanthins, and betalains with radical scavenging capacity (RSC). They have abundant phytonutrients and antioxidant components, such as pigments, vitamins, phenolics, and flavonoids. Eight selected genotypes (four genotypes from each species) of underutilized Amaranthus leafy vegetables were evaluated for phytonutrients, pigments, vitamins, phenolics, flavonoids, and antioxidants in a randomized complete block design under ambient field conditions with three replicates. The studied traits showed a wide range of variations across eight genotypes of two species of Amaranthus leafy vegetables. The highest fat, β-xanthins, K, dietary fiber, Mg, β-cyanins, Mn, chlorophyll ab, Zn, TP, TF, betalains, chlorophyll a content, and (RSC) (DPPH) and RSC (ABTS+) were obtained from A. tricolor accessions. Conversely, the highest protein, Cu, carbohydrates, Ca, and chlorophyll b content were obtained from A. lividus accessions. The highest dry matter, carotenoids, Fe, energy, and ash were obtained from A. tricolor and A. lividus. The accession AT2 confirmed the highest vit. C and RSC (DPPH) and RSC (ABTS+); AT5 had the highest TP content; and AT12 had the highest TF content. A. tricolor accessions had high phytochemicals across the two species, such as phytopigments, vitamins, phenolics, antioxidants, and flavonoids, with considerable nutrients and protein. Hence, A. tricolor accessions can be used as high-yielding cultivars comprising ample antioxidants. The correlation study revealed that vitamin C, pigments, flavonoids, β-carotene, and phenolics demonstrated a strong RSC, and showed a substantial contribution to the antioxidant potential (AP) of A. tricolor. The investigation exposed that the accessions displayed a plentiful origin of nutritional values, phytochemicals, and AP with good quenching ability of reactive oxygen species (ROS) that provide enormous prospects for nourishing the mineral-, antioxidant-, and vitamin-threatened community.

Biochemistry of Amaranthus polyphenols and their potential benefits on gut ecosystem: A comprehensive review of the literature

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Amaranthus is phytonutrients-rich plant distributed worldwide and has been recognized as having medicinal value in traditional use against several diseases and conditions. There are a large amount of research data on the polyphenol profiles of Amaranthus plants and their links with potential benefits against gastrointestinal disorders.

AIM OF THE REVIEW

This review article aims to provide a comprehensive review of Amaranthus phenolic compounds and their microbial metabolites, as well as the biological and/or pharmacological effects of those compounds/metabolites.

METHODOLOGY

The relevant information about the genus Amaranthus was collected from various sources and databases, including Google Scholar, Google Books, PubMed, Web of Science, Scopus, Science Direct, and other internet sources. The World Flora Online (2021) database was used to verify the scientific names of the plants.

RESULTS

Comprehensive review of identified compounds in Amaranthus plants revealed the presence of phenolic acids, flavonoids, and coumarins in each part of the plants. The biotransformation by gut microbiota enzymes prominently produces diverse bioactive metabolites that are potentially active than their precursors. Lines of the evidence support the beneficial roles of Amaranthus extracts in several gastrointestinal diseases, particularly with the polar extracts of several plant parts. Dietary fibers in Amaranthus plants also coordinate the alteration of gut microbiota-related metabolisms and may be beneficial to certain gastrointestinal disorders in particular, such as constipation.

CONCLUSIONS

Amaranthus plants are rich in polyphenols and dietary fibers. Several microbial metabolites are biologically active, so alteration of gut microbiota is largely linked to the metabolic feature of the plants. Based on the evidence available to date, several Amaranthus plants containing a combination of phytonutrients, particularly polyphenols and dietary fibers, may be a promising candidate that is of interest to be further developed for use in the treatment of certain gastrointestinal conditions/disorders.

Color attributes, betacyanin, and carotenoid profiles, bioactive components, and radical quenching capacity in selected Amaranthus gangeticus leafy vegetables

Four selected A. gangeticus accessions were evaluated in terms of color attributes, phytopigments, including betaxanthin, betacyanin, and carotenoid profiles, proximate, minerals, and antioxidant capacity (AC). Color attributes, phytopigments, proximate, minerals, and AC of A. gangeticus significantly varied across the accessions. For the first time, we identified four betacyanin compounds, such as amaranthine, iso-amaranthine, betanin, iso-betanin. We also identified five carotenoid compounds zeaxanthin neoxanthin, violaxanthin, lutein, and pro-vitamin A in A. gangeticus accessions. A. gangeticus contained adequate carbohydrates, protein, moisture, and dietary fiber. We found adequate iron, manganese, copper, zinc, sodium, molybdenum, boron, potassium, calcium, magnesium, phosphorus, sulfur in A. gangeticus accessions. The accessions LS7 and LS9 had considerable color attributes, betacyanin, and carotenoid compounds, proximate, nutraceuticals, betalain, betaxanthin, and AC that could be used as preferable potent antioxidant varieties for consumption as sources of phytopigments, nutraceuticals, and antioxidants. The correlation study revealed that antioxidant constituents of A. gangeticus accession were strongly associated with AC. The identified components of betacyanin and carotenoid in A. gangeticus demands detail pharmacological study. The baseline data on color attributes, betacyanin, and carotenoid profiles, betaxanthins, betalains, and AC obtained in this present study could contribute to the scientific evaluation of pharmacologically active principles in A. gangeticus.

Nutraceuticals, phytochemicals, and radical quenching ability of selected drought-tolerant advance lines of vegetable amaranth

BACKGROUND

Vegetable amaranth is a source of natural phytopigments and functional components of the commercial food industry for sustainable health benefits across the globe. It is guessed that recently identified amaranth (drought-tolerant) genotypes may contain ample phytopigments and phytochemicals suitable to extract juice as drinks. Hence, phytopigments and phytochemicals content of amaranth were assessed in detail for suitability as drinks to feed the phytochemicals deficient community across the globe.

RESULTS

The selected amaranth contained adequate carbohydrates, protein, moisture, and dietary fiber, phytopigments, minerals, phytochemicals including the ability to scavenge radicals. Nine flavonoids compounds were estimated in amaranth genotypes including six flavonols, one flavanol, one flavone, and one flavanone. It is the first effort in which we identified one flavonol such as myricetin, one flavanol, such as catechin, one flavone i. e., apigenin, and one flavanone, like naringenin in drought-tolerant vegetable amaranth. Across six flavonols, quercetin and rutin were the most noteworthy compounds followed by myricetin and isoquercetin. Across the accessions, AT7 and AT15 had abundant phytochemicals, and radical quenching ability including considerable proximate, nutraceuticals, and phytopigments in comparison to the accessions AT3 and AT11. AT15 demonstrated the maximum total flavonols including the highest rutin and hyperoside. AT7 showed high total flavonols including the highest quercetin, isoquercetin, myricetin, and kaempferol. The association of values revealed that studied phytopigments and phytochemicals of vegetable amaranth accessions demonstrated good radical quenching ability of 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and 2,2- Diphenyl-1-picrylhydrazyl equivalent to Trolox.

CONCLUSIONS

These advance lines AT7 and AT15 had abundant nutraceuticals, phytopigments, and phytochemicals including radical quenching ability. These lines might significantly contribute to the promotion of health benefits and feeding the community across the globe deficit in nutraceuticals and antioxidants. Identified flavonoid compounds open the new route for pharmacological study.

Bioactive Components and Radical Scavenging Activity in Selected Advance Lines of Salt-Tolerant Vegetable Amaranth

Four selected advance lines of salt-tolerant vegetable amaranth were evaluated for proximate, nutraceuticals, pigments, phytochemicals, and antioxidants components antioxidants activity in completely randomized block design (RCBD) design in three replicates. Salt-tolerant vegetable amaranth contained adequate carbohydrates, protein, moisture, and dietary fiber. The remarkable contents of iron, manganese, copper, zinc, sodium, molybdenum, boron, potassium, calcium, magnesium, phosphorus, sulfur, betacyanins, betalains, betaxanthins, chlorophylls, ascorbic acid, polyphenols, flavonoids, and antioxidant potentiality were found in salt-tolerant vegetable amaranth. The genotypes LS7 and LS9 had abundant proximate, nutraceuticals, pigments, phytochemicals, and antioxidants compared to the genotypes LS3 and LS5. Salt-tolerant vegetable amaranth demonstrated high content of flavonoid compounds including flavonols such as rutin, kaempferol, isoquercetin, myricetin, hyperoside, and quercetin; flavanol, such as catechin; flavone such as apigenin; and flavanone, such as naringenin. For the first time, we identified one flavonol such as myricetin; one flavanol, such as catechin; one flavone such as apigenin; and one flavanone, such as naringenin in salt-tolerant vegetable amaranth. Across six flavonols, rutin and quercetin were identified as the most prominent compounds followed by isoquercetin and myricetin in selected salt-tolerant vegetable amaranths. Across the genotypes, LS7 exhibited the highest flavonols such as rutin, kaempferol, isoquercetin, myricetin, hyperoside, and quercetin as well as the highest flavanols, such as catechin; flavones such as apigenin; and flavanones, such as naringenin. It revealed from the correlation study that antioxidant components of salt-tolerant vegetable amaranth genotypes exhibited good radical quenching capacity of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl equivalent to Trolox. The two genotypes LS7 and LS9 of vegetable amaranth containing excellent sources of proximate, nutraceuticals, pigments, phytochemicals, and antioxidants components could be used as potent antioxidants to attaining nutrients and antioxidant sufficiency in the saline prone area of the globe. We can extract colorful juice from the genotypes LS7 and LS9 as drink purposes for consuming the nutraceuticals and antioxidant deficient community in the saline prone area around the world. However, further detail experimentation is required to confirm the standardization and stabilization of functional components of vegetable amaranth for extraction of juice as drinks.

Nutritional and bioactive constituents and scavenging capacity of radicals in Amaranthus hypochondriacus

A. hypochondriacus leaves contained ample phytopigments including betalain, anthocyanin, β-xanthin, β-cyanin, and bioactive phytochemicals of interest in the industry of food. We have been evaluating the possibility of utilizing phytopigments of amaranth and bioactive constituents for making drinks. Therefore, we evaluated bioactive phytopigments and compounds including the potentiality of antioxidants in A. hypochondriacus leaves. A. hypochondriacus leaves have abundant protein, carbohydrates, and dietary fiber. We found considerable levels of inorganic minerals including magnesium, calcium, potassium (3.88, 3.01, 8.56 mg g-1), zinc, manganese, copper, iron (16.23, 15.51, 2.26, 20.57 µg g-1), chlorophyll b, chlorophyll ab chlorophyll a (271.08, 905.21, 636.87 μg g-1), scavenging capacity of radicals (DPPH, ABTS+) (33.46, 62.92 TEAC μg g-1 DW), total polyphenols (29.34 GAE μg g-1 FW), β-xanthin, betalain, β-cyanin (584.71, 1,121.93, 537.21 ng g-1), total flavonoids (170.97 RE μg g-1 DW), vitamin C, β-carotene, carotenoids (184.77, 82.34, 105.08 mg 100 g-1) in A. hypochondriacus leaves. The genotypes AHC6, AHC4, AHC11, AHC5, and AHC10 had a good scavenging capacity of radicals. Polyphenols, phytopigments, flavonoids, and β-carotene of A. hypochondriacus had potential antioxidant activity. Extracted juice of A. hypochondriacus can be an ample source of phytopigments and compounds for detoxification of reactive oxygen species (ROS) and attaining nutritional and antioxidant sufficiency.

Polyphenol and flavonoid profiles and radical scavenging activity in leafy vegetable Amaranthus gangeticus

BACKGROUND

Red amaranth (Amaranthus gangeticus L.) has great diversity in Bangladesh, India, and South East Asia with multipurpose uses. The bright red-violet colored A. gangeticus is a popular and low-cost leafy vegetable in the Asian continent including Bangladesh and India because of attractive leaf color, taste, adequate nutraceuticals, phenolic compounds, and sole source of betalains. The natural colors and phenolic compounds of this species have a significant role in promoting the health-benefit including the scavenging capacity of radicals, the colorant of food products, and play a vital role in the industry of foods. However, phenolic profiles and radical scavenging activity of this species have not been evaluated. Hence, for the first time, four selected advance lines of A. gangeticus were characterized for phenolic profiles, antioxidant constituents, and antioxidant potentiality.

RESULTS

A. gangeticus genotypes are abundant sources of phenolic profiles and antioxidant constituents with good radical quenching capacity that differed across the genotypes. Twenty-five phenolic acids and flavonoids, such as protocatechuic acid, salicylic acid, gentisic acid, gallic acid, β-resorcylic acid, vanillic acid, p-hydroxybenzoic acid, chlorogenic acid, ellagic acid, syringic acid, ferulic acid, kaempferol, m-coumaric acid, trans-cinnamic acid, quercetin, p-coumaric acid, apigenin, caffeic acid, rutin, sinapic acid, isoquercetin, naringenin, myricetin, catechin, and hyperoside were identified in A. gangeticus accessions. A. gangeticus accessions LS7 and LS9 demonstrated ample phenolic acids, flavonoids, antioxidant constituents, and antioxidant potentiality. It revealed from the correlation study that antioxidant components of A. gangeticus genotypes exhibited good radical scavenging activities. The genotypes LS7 and LS9 could be directly used as phenolic profiles, antioxidant constituents, and antioxidant activity enrich cultivars.

CONCLUSIONS

The identified compounds of phenolic acids and flavonoids in A. gangeticus privilege the comprehensive study of pharmacology. The basic information on phenolic profiles and antioxidant constituents achieved in the present study will provide the scientist's forum for the scientific assessment of these compounds in A. gangeticus.

Leaf pigmentation, its profiles and radical scavenging activity in selected Amaranthus tricolor leafy vegetables

The selected A. tricolor accessions contained abundant color attributes, betacyanin, carotenoids, betalains, betaxanthins, and antioxidants potentiality that varied in terms of genotypes. For the first time, we identified 4 betacyanins, and 5 carotenoid compounds in A. tricolor genotypes. The genotype VA14 and VA16 had abundant color attributes, betacyanin such as amaranthine, iso-amaranthine, betanin, iso-betanin, and antioxidants potentiality. These two genotypes having an excellent source of color attributes, betacyanins, betalains, betaxanthins, and antioxidants potentiality could be used as potent antioxidant varieties. The genotype VA11 and VA16 had abundant carotenoid components, such as zeaxanthin, lutein, violaxanthin, neoxanthin, total xanthophylls, and beta-carotene. The genotype VA11 and VA16 had abundant carotenoid components that could be used as carotenoid enrich varieties. It revealed from the correlation study that pigment profiles of A. tricolor genotypes exhibited high quenching capacity of radicals. These accessions have high antioxidant potentials and great opportunity to make drinks, preservatives, and colorant of food products to feed the community deficient in antioxidants. The identified components of betacyanins and carotenoids in A. tricolor require comprehensive pharmacological study. The baseline data on color attributes, betacyanins profile, carotenoids profile, betaxanthins, betalains and antioxidant potentiality obtained in the present study could contribute to pharmacologists for evaluating these components scientifically in A. tricolor.

Phenolic profiles and antioxidant activities in selected drought-tolerant leafy vegetable amaranth

Four selected advance lines of drought-tolerant leafy vegetable amaranth were characterized for phenolic profiles, vitamins, and antioxidant activities. The selected advance lines exhibited differences in terms of genotypes with remarkable phenols, vitamins, flavonoids content, and potential radical quenching capacity. We identified twenty-five phenolic and flavonoid compounds including protocatechuic acid, salicylic acid, gentisic acid, gallic acid, β-resorcylic acid, vanillic acid, p-hydroxybenzoic acid, chlorogenic acid, ellagic acid, syringic acid, ferulic acid, kaempferol, m-coumaric acid, trans-cinnamic acid, quercetin, p-coumaric acid, apigenin, caffeic acid, rutin, sinapic acid, isoquercetin, naringenin, myricetin, catechin, and hyperoside. The selected advance lines VA14 and VA16 had abundant phenols, vitamins, flavonoids, and antioxidants potentiality. The selected drought-tolerant leafy vegetable amaranth showed high antioxidant potentiality as phenols, vitamins, flavonoids of these lines had a significant positive correlation with antioxidant capacities equivalent to Trolox using 2,2-diphenyl-1-picrylhydrazyl and ABTS+. Therefore, drought-tolerant leafy vegetable amaranth VA14 and VA16 can be grown in semi-arid and drought-prone areas in the world to attaining vitamins and antioxidant sufficiency. The phenolic and flavonoids compounds identified in drought-tolerant leafy vegetable amaranth demand a comprehensive pharmacological study. The baseline data on phenolic and flavonoids compounds obtained in the present study will contribute to the scientist forum for the scientific evaluation of these compounds in vegetable amaranth.

The Response of Salinity Stress-Induced A. tricolor to Growth, Anatomy, Physiology, Non-Enzymatic and Enzymatic Antioxidants

An investigation was carried out to elucidate growth, anatomical, physiological, and major ROS detoxification pathways involved in the tolerance of A. tricolor under salinity stress. Both VA14 and VA3 varieties exhibited the reduction in relative water content (RWC), photosynthetic pigments, growth, increased electrolyte leakage (EL), and leaf anatomy adaptation under salinity stress, whereas VA14 was well adapted and performed better compared to VA3. Higher ROS accumulation was demonstrated in the sensitive variety (VA3) in comparison to the tolerant variety (VA14). Salinity stress changed the cellular antioxidant pool by increasing total carotenoids, ascorbate, proline, total polyphenol content (TPC), total flavonoid content (TFC), and total antioxidant capacity (TAC) in both varieties. Although a higher increment was demonstrated in the tolerant variety, the proline increment was much more pronounced in the sensitive variety. Non-enzymatic antioxidant, ascorbate, carotenoids, TPC, TFC, TAC, and antioxidant enzymes SOD and APX were noted to be a major H2O2 detoxifier in the tolerant A. tricolor variety, where there is a comparatively lower H2O2 load. It was complemented by GPOX and CAT activity at a comparatively higher H2O2 load (in the sensitive variety). SOD contributed to the dismutation of superoxide radical (SOR) both in the tolerant and sensitive varieties; however, it greatly contributed to the dismutation of SOR in the tolerant variety. The increase in SOD, ascorbate, and APX makes it predominantly evident that SOD and the AsA-GSH cycle had greatly contributed to quench reactive oxygen species (ROS) of the tolerant variety of A. tricolor.

The Probable Use of Genus amaranthus as Feed Material for Monogastric Animals

This review presents, discusses, and provides a comprehensive understanding of the potential use of amaranth as feed for monogastric animals. Amaranth is an ancient nutritious crop that has been cultivated for multiple purposes. In America, Asia, and Africa, the leaves of amaranth species are used as vegetables. The change in climatic conditions globally has resulted in shortages of rainfall, unpredictable weather, and lack of inputs such as fertilizer. This has led to scarcity of protein sources in the market and instability in prices which makes it necessary to consider alternative ingredients in poultry, pigs, fish, and rabbits feed formulation. Amaranth is rich in fiber, proteins, vitamins, minerals, and phenolic compounds which have some health benefits in animals and can be used to improve productivity. It also contains anti-nutritional factors which can be reduced by several processing methods. Moreover, its use in monogastric nutrition is useful because amaranth has shown to improve monogastric productivity without having any adverse effect on animals' productivity. Thus, from this review, it can be concluded that amaranth leaves and grains can be used successfully in monogastric animals though different processing methods which might need to be employed in order to reduce anti-nutritional factors before use in animals.

Polyphenols in amaranth (A. manteggazianus) flour and protein isolate: Interaction with other components and effect of the gastrointestinal digestion

In this work, there were analysed the interaction between phenolics present in amaranth flour (F) and amaranth protein isolate (I) with other components, as well as the effect of the gastrointestinal digestion on them (Fd and Id). Extractions were performed under different conditions (temperature, acid, organic solvent, alkali). Methanol/water extracts (25 °C and 80 °C) from F showed the presence of isoquercetin/rutin, quercetin, kaempferol and two unidentified peaks (II and III). In the presence of acid (much more evident at 80 °C), the extraction of some components increased: catechin, 4-hydroxibenzoic acid, isoquercetin/rutin, II, III. When methanol/acetone/water extraction was performed, p-coumaric acid and a new unidentified peak (IV) were observed. About 15% of the total phenol -namely; p-coumaric, rutin/isoquercetin, and kaempferol- were linked to the protein fraction. After the proteins were isolated (I), the amount of some of the compounds which were originally present in a soluble form (e. g. catechin) and in the protein-bound fraction were decreased. Simulated gastrointestinal digestion of flour released some phenolics (catechin, phenolic acids) that were ligated to proteins, and they significantly incremented the ORAC and ABTS activity of most of the extracts. Isoquercetin/rutin, quercetin and kaempferol remained after digestion. Extracts from the digested protein isolate presented differences in the composition and lower ORAC and/or ABTS activities for some of them. The study of the effect of the simulated gastrointestinal digestion process on bioaccessibility and on antioxidant activity (an aspect that, to our knowledge, has not been previously studied on amaranth polyphenols) yielded promising results, which suggest that amaranth flour is a potential antioxidant functional ingredient.

Seed characterization and early nitrogen metabolism performance of seedlings from Altiplano and coastal ecotypes of Quinoa

BACKGROUND

Early seed germination and a functional root system development during establishment are crucial attributes contributing to nutrient competence under marginal nutrient soil conditions. Chenopodium quinoa Willd (Chenopodiaceae) is a rustic crop, able to grow in marginal areas. Altiplano and Coastal/Lowlands are two representative zones of quinoa cultivation in South America with contrasting soil fertility and edaphoclimatic conditions. In the present work, we hypothesize that the ecotypes of Quinoa from Altiplano (landrace Socaire) and from Coastal/Lowland (landrace Faro) have developed differential adaptive responses in order to survive under conditions of low availability of N in their respective climatic zones of Altiplano and Lowlands. In order to understand intrinsic differences for N competence between landraces, seed metabolite profile and germinative capacity were studied. Additionally, in order to elucidate the mechanisms of N uptake and assimilation at limiting N conditions during establishment, germinated seeds of both landraces were grown at either sufficient nitrate (HN) or low nitrate (LN) supply. We studied the photosynthetic performance, protein storage, root morphometrical parameters, activity and expression of N-assimilating enzymes, and the expression of nitrate transporters of roots in plants submitted to the different treatments.

RESULTS

Seeds from Socaire landrace presented higher content of free N-related metabolites and faster seed germination rate compared to Faro landrace. Seedlings of both ecotypes presented similar physiological performance at HN supply, but at LN supply their differences were exalted. At LN, Socaire plants showed an increased root biomass (including a higher number and total length of lateral roots), a differential regulation of a nitrate transporter (a NPF6.3-like homologue) belonging to the Low Affinity Transport System (LATS), and an upregulation of a nitrate transporter (a NRT2.1-like homologue) belonging to the High Affinity nitrate Transport System (HATS) compared to Faro. These responses as a whole could be linked to a higher amount of stored proteins in leaves, associated to an enhanced photochemical performance in Altiplano plants, in comparison to Lowland quinoa plants.

CONCLUSIONS

These differential characteristics of Socaire over Faro plants could involve an adaptation to enhanced nitrate uptake under the brutal unfavorable climate conditions of Altiplano.

Nutrients, minerals, antioxidant pigments and phytochemicals, and antioxidant capacity of the leaves of stem amaranth

We evaluated 17 genotypes of stem amaranth (Amaranthus lividus) in terms of dietary fiber, moisture, carbohydrates, fat, ash, gross energy, protein, minerals, phytopigments, total antioxidant capacity (TAC), vitamins, total flavonoids (TFC), total polyphenols (TPC) and their variations. Stem amaranth leaves have abundant dietary fiber, moisture, carbohydrates, and protein. We found significant amount of potassium, calcium, magnesium (9.61, 24.40, and 29.77 mg g-1 DW), iron, manganese, copper, zinc, (1131.98, 269.89, 25.03, and 1006.53 µg g-1 DW), phytopigments such as chlorophyll a, chlorophyll ab chlorophyll b, (27.76, 42.06, and 14.30 mg 100 g-1 FW), betalain, betaxanthin, betacyanin (62.92, 31.81, 31.12 µg 100 g-1 FW), total carotenoids, beta-carotene (1675.38, 1289.26 µg g-1 FW), vitamin C (1355.46 µg g-1 FW), TPC, TFC (228.63 GAE and 157.42 RE µg g-1 DW), and TAC (DPPH, ABTS+) (26.61, 51.73 TEAC µg g-1 DW) in the leaves of stem amaranth. Genotypes exhibited a wide range of variations. Three genotypes DS40, DS30, and DS26 could be used as an antioxidant profile enriched stem amaranth. Phenolics, phytopigments, flavonoids, and vitamins of stem amaranth leaves exhibited strong antioxidant activity. Stem amaranth could be a potential source of dietary fiber, moisture, carbohydrates, protein, minerals, phenolics, phytopigments, flavonoids, and vitamins in our daily diet for attaining nutritional and antioxidant sufficiency.

Nutrients, minerals, pigments, phytochemicals, and radical scavenging activity in Amaranthus blitum leafy vegetables

A. blitum is good sources of abundant natural antioxidant phytopigments such as anthocyanin, betalain, betaxanthin, and betacyanin and antioxidant phytochemicals of interest in the food industry. The chances of utilizing amaranth pigments and phytochemicals had been evaluated for extracting colorful juice as drink purposes. Hence, the presence of nutrients, phytopigments, phytochemicals, and radical scavenging activity of selected A. blitum leafy vegetables were evaluated. Leaves of A. blitum have considerable fiber, moisture, protein, and carbohydrates. It has considerable magnesium, calcium, potassium (30.42, 24.74, 10.24 mg g-1), zinc, iron, copper, manganese, (878.98, 1153.83, 26.13, 207.50 µg g-1), phytopigments such as chlorophyll a, chlorophyll ab, chlorophyll b, (63.69, 90.60, 29.32 mg 100 g-1), betalain, betaxanthin, betacyanin (112.01, 58.38, 53.63 µg 100 g-1), vitamin C (1848.15 µg g-1), total carotenoids, β-carotene (1675.38, 1281.66 µg g-1), TPC, TFC (253.45 GAE and 162.97 RE µg g-1 DW), and TAC (29.46, 55.72 µg g-1 DW in Tolax equivalent DPPH and ABTS+ radical scavenging capacity) in A. blitum. The accessions DS3, DS6, DS8, and DS12 exhibited the highest TAC in Trolox equivalent DPPH and ABTS+ radical scavenging capacity, flavonoids, and considerable phytopigments. These accessions had excellent antioxidant profiles along with high yielding potentiality. Hence, A. blitum provides an excellent source of proximate, phenolics, minerals, flavonoids, vitamins, and phytopigments to address the nutritional and antioxidant deficiency in daily diet.

Nutritional and antioxidant components and antioxidant capacity in green morph Amaranthus leafy vegetable

Amaranth has two morphological types described as red and green morphs. Previous studies have extensively characterised red morph amaranth regarding both morphological and chemical properties including antioxidant activity, antioxidant phytochemical profile, mineral content and proximate composition. However, there is scarce information concerning green morph amaranth. Hence, the present study evaluated 12 green morph genotypes for proximate composition, antioxidant activity, antioxidant pigments, minerals, and phytochemicals. Green morph amaranth was found to contain abundant carbohydrates, dietary fiber and protein. We found notable levels of inorganic minerals including potassium, calcium, magnesium, iron, manganese, copper and zinc. Antioxidant capacity quantified as free radical quenching capacity varied between 27 and 48 μg g-1 Trolox equivalents. We additionally quantified antioxidants, including total phenolics, total flavonoid equivalents and vitamin C, as well as the antioxidant pigments carotenoids, chlorophylls and betalains. These data indicated that four green morph genotypes could be considered as enriched in their antioxidant profiles. Green morph amaranth could be a potential source of nutritional components and antioxidant phytochemicals in the human diet providing opportunities to address mineral nutrient deficiencies and provide an antioxidant rich food.

Protein, dietary fiber, minerals, antioxidant pigments and phytochemicals, and antioxidant activity in selected red morph Amaranthus leafy vegetable

Amaranth has two morphological types (morphs), one is red and another is green morph. Red morph amaranth is a marvelous source of nutrients, antioxidant pigments, minerals, and phytochemicals compared to green morph amaranth. For this purpose, we selected 25 red morph genotypes to evaluate in terms of proximate, minerals, antioxidant pigments and phytochemicals and antioxidant activity in RCBD design in three replicates. The leaves of red morph amaranth are an excellent source of dietary fiber, carbohydrates, moisture, and protein. We found remarkable potassium, calcium, magnesium (24.96, 10.13, 30.01 mg g-1), iron, manganese, copper, zinc (1089.19, 243.59, 25.77, 986.61 μg g-1), chlorophyll a, chlorophyll b (31.79, 16.05 mg 100 g-1), β-cyanins, total flavonoids (102.10 RE μg g-1 DW), β-xanthins, betalains (33.30, 33.09, 66.40 μg 100 g-1), carotenoids, total phenolics (172.23 GAE μg g-1 DW), β-carotene (1225.94, 1043.18 μg g-1), vitamin C (955.19 μg g-1), and antioxidant activity (DPPH and ABTS+) (19.97 and 39.09 TEAC μg g-1 DW) in the red morph amaranth leaves. We can select the genotype RA5, RA8, RA18, RA22, and RA25 as antioxidant-enriched red morph amaranth. It revealed that amaranth β-cyanins, phenolics, betalains, flavonoids, β-xanthins, carotenoids, vitamin C, and β-carotene had strong antioxidant activity. These phytochemicals contributed significantly in the antioxidant potentials of red morphs amaranth. Red morph amaranth could be a potential source of nutrients, antioxidant pigments, minerals, and phytochemicals as these compounds scavenged ROS and served as potential antioxidants in our daily diet to attaining nutritional and antioxidant sufficiency.

Antioxidant constituents of three selected red and green color Amaranthus leafy vegetable

Red color (A. tricolor) genotypes are an excellent source of pigments, such as betalain (1122.47 ng g-1 FW), β-xanthin (585.22 ng g-1 FW), β-cyanin (624.75 ng g-1 FW), carotenoids (55.55 mg 100 g-1 FW), and antioxidant phytochemicals, such as vitamin C (122.43 mg 100 g-1 FW), TFC (312.64 RE µg g-1 DW), TPC (220.04 GAE µg g-1 DW), TAC (DPPH and ABTS+) (43.81 and 66.59 TEAC µg g-1 DW) compared to green color (A. lividus) genotype. Remarkable phenolic acids, such as salicylic acid, vanillic acid, protocatechuic acid, gallic acid, gentisic acid, β-resorcylic acid, p-hydroxybenzoic acid, syringic acid, ellagic acid, chlorogenic acid, sinapic acids, trans-cinnamic acid, m-coumaric acid, caffeic acid, p-coumaric acid, ferulic acid, and flavonoids, such as rutin, hyperoside, isoquercetin, myricetin, quercetin, apigenin, kaempferol, and catechin were observed in the red color amaranth genotypes, which was much higher compared to the green color amaranth genotype. We newly identified four flavonoids such as quercetin, catechin, myricetin, and apigenin in amaranth. Among the three selected advanced genotypes studied the red color genotype VA13 and VA3 had abundant antioxidant pigments, phytochemicals, phenolic acids, flavonoids, and antioxidant activity could be selected for extracting colorful juice. Correlation study revealed that all antioxidant constituents of red color amaranth had strong antioxidant activity. The present investigation revealed that two red color genotypes had an excellent source of antioxidants that demand detail pharmacological study.

Salinity stress enhances color parameters, bioactive leaf pigments, vitamins, polyphenols, flavonoids and antioxidant activity in selected Amaranthus leafy vegetables

BACKGROUND

Amaranthus tricolor is a unique source of betalain (β-cyanin and β-xanthin) and a source of natural antioxidants, such as leaf pigments, vitamins, polyphenols and flavonoids in leafy vegetables. It has substantial importance for the food industry, since these compounds detoxify reactive oxygen species in humans and are involved in defense against several diseases. In addition, previous research has shown that salt stress elevates these compounds in many leafy vegetables. Therefore, we evaluated the effect of salinity stress on these compounds.

RESULTS

Three selected A. tricolor genotypes were studied under three salinity levels to evaluate the response of these compounds. Genotype, salinity stress and their interactions significantly affected all the traits studied. A significant and remarkable increase in L, a*, b*, chroma, β-cyanin, β-xanthin, betalain, total carotenoids, β-carotene, ascorbic acid, total polyphenolic content, total flavonoid content and total antioxidant capacity were observed under 50 and 100 mmol L^-1 NaCl concentrations. Bioactive leaf pigments, β-carotene, vitamin C, phenolics and flavonoids showed good antioxidant activity due to positive and significant interrelationships with total antioxidant capacity.

CONCLUSIONS

Amaranthus tricolor can tolerate salinity stress without compromising the high quality of the final product. Therefore, it could be a promising alternative crop in saline-prone areas around the globe. © 2018 Society of Chemical Industry.

Salinity stress accelerates nutrients, dietary fiber, minerals, phytochemicals and antioxidant activity in Amaranthus tricolor leaves

Impact of salinity stress were investigated in three selected Amaranthus tricolor accessions in terms of nutrients, dietary fiber, minerals, antioxidant phytochemicals and total antioxidant activity in leaves. Salinity stress enhanced biochemical contents and antioxidant activity in A. tricolor leaves. Protein, ash, energy, dietary fiber, minerals (Ca, Mg, Fe, Mn, Cu, Zn, and Na), β-carotene, ascorbic acid, total polyphenol content (TPC), total flavonoid content (TFC), total antioxidant capacity (TAC) (DPPH and ABTS+) in leaves were increased by 18%, 6%, 5%, 16%, 9%, 16%, 11%, 17%, 38%, 20%, 64%, 31%, 22%, 16%, 16%, 25% and 17%, respectively at 50 mM NaCl concentration and 31%, 12%, 6%, 30%, 57%, 35%, 95%, 96%, 82%, 87%, 27%, 63%, 82%, 39%, 30%, 58% and 47%, respectively at 100 mM NaCl concentration compared to control condition. Contents of vitamins, polyphenols and flavonoids showed a good antioxidant activity due to positive and significant interrelationships with total antioxidant capacity. It revealed that A. tricolor can tolerate a certain level of salinity stress without compromising the nutritional quality of the final product. This report for the first time demonstrated that salinity stress at certain level remarkably enhances nutritional quality of the leafy vegetable A. tricolor. Taken together, our results suggest that A. tricolor could be a promising alternative crop for farmers in salinity prone areas- in the tropical and sub-tropical regions with enriched nutritional contents and antioxidant activity.

Drought stress enhances nutritional and bioactive compounds, phenolic acids and antioxidant capacity of Amaranthus leafy vegetable

BACKGROUND

Bioactive compounds, vitamins, phenolic acids, flavonoids of A. tricolor are the sources of natural antioxidant that had a great importance for the food industry as these detoxify ROS in the human body. These natural antioxidants protect human from many diseases such as cancer, arthritis, emphysema, retinopathy, neuro-degenerative cardiovascular diseases, atherosclerosis and cataracts. Moreover, previous literature has shown that drought stress elevated bioactive compounds, vitamins, phenolics, flavonoids and antioxidant activity in many leafy vegetables. Hence, we study the nutritional and bioactive compounds, phenolic acids, flavonoids and antioxidant capacity of amaranth under drought stress for evaluation of the significant contribution of these compounds in the human diet.

RESULTS

The genotype VA3 was assessed at four drought stress levels that significantly affected nutritional and bioactive compounds, phenolic acids, flavonoids and antioxidant capacity. Protein, ash, energy, dietary fiber, Ca, K, Cu, S, Mg, Mn, Mo, Na, B content, total carotenoids, TFC, vitamin C, TPC, TAC (DPPH), betacarotene, TAC (ABTS+), sixteen phenolic acids and flavonoids were remarkably increased with the severity of drought stress. At moderate and severe drought stress conditions, the increments of all these components were more preponderant. Trans-cinnamic acid was newly identified phenolic acid in A. tricolor. Salicylic acid, vanilic acid, gallic acid, chlorogenic acid, Trans-cinnamic acid, rutin, isoquercetin, m-coumaric acid and p-hydroxybenzoic acid were the most abundant phenolic compounds in this genotype.

CONCLUSIONS

In A. tricolor, drought stress enhanced the quantitative and qualitative improvement of nutritional and bioactive compounds, phenolic acids, flavonoids and antioxidants. Hence, farmers of semi-arid and dry areas of the world could be able to grow amaranth as a substitute crop.

Augmentation of leaf color parameters, pigments, vitamins, phenolic acids, flavonoids and antioxidant activity in selected Amaranthus tricolor under salinity stress

Amaranthus tricolor genotype VA13 was evaluated under four salinity stress in terms of color parameters, leaf pigments, β-carotene, vitamin C, TPC, TFC, TAC, phenolic acids and flavonoids. Salinity stress significantly increases all the studied traits. The increments of all these compounds were high under moderate and severe salinity stress compared to control condition. In this study, trans-cinnamic acid was newly identified phenoic acid in A. tricolor. Salicylic acid, vanilic acid, trans-cinnamic acid, gallic acid, chlorogenic acid, rutin, isoquercetin and m-coumaric acid were the most abundant phenolic compounds of amaranth that increased with the severity of salinity stress. A. tricolor leaves are good source of pigments, β-carotene, vitamin C, bioactive compounds, phenolic acids, flavonoids and antioxidants. In salt-stressed amaranth, correlation studies revealed strong antioxidant activity of leaf pigments, β-carotene, vitamin C, TPC, TFC. These bioactive compounds played a vital role in scavenging ROS and could be beneficial to human nutrition by serving as a good antioxidant and antiaging source in human health benefit. A. tricolor cultivated under salinity stress conditions can contribute a high quality of the final product in terms of leaf pigments, bioactive compounds, phenolic acids, flavonoids and antioxidants. It can be a promising alternative crop in saline-prone areas.

Drought Stress Effects on Growth, ROS Markers, Compatible Solutes, Phenolics, Flavonoids, and Antioxidant Activity in Amaranthus tricolor

Four selected Amaranthus tricolor cultivars were grown under four irrigation regimes (25, 50, 80, and 100% field capacity) to evaluate the mechanisms of growth and physiological and biochemical responses against drought stress in randomized complete block design with three replications. Drought stress led to decrease in total biomass, specific leaf area, relative water content (RWC), photosynthetic pigments (chlorophyll a, chlorophyll b, chlorophyll ab), and soluble protein and increase in MDA, H₂O₂, EL, proline, total carotenoid, ascorbic acid, polyphenols, flavonoids, and antioxidant activity. However, responses of these parameters were differential in respect to cultivars and the degree of drought stresses. No significant difference was observed in control and LDS for most of the traits. The cultivars VA14 and VA16 were identified as more tolerant to drought and could be used for further evaluations in future breeding programs and new cultivar release programs. Positively significant correlations among MDA, H₂O₂, compatible solutes, and non-enzymatic antioxidant (proline, TPC, TFC, and TAC) suggested that compatible solutes and non-enzymatic antioxidant played vital role in detoxifying of ROS in A. tricolor cultivar. The increased content of ascorbic acid indicated the crucial role of the ASC-GSH cycle for scavenging ROS in A. tricolor.

Phytochemicals in quinoa and amaranth grains and their antioxidant, anti-inflammatory, and potential health beneficial effects: a review

Quinoa (Chenopodium quinoa Willd.) and amaranth (Amaranthus cruentus L.) are pseudocereal grains rich in both macronutrients and micronutrients including vitamins and minerals. The proteins are particularly of high nutritional quality due to the outstanding balance of essential amino acids. However, recent research strongly suggests that nonessential nutrients such as phytochemicals of quinoa and amaranth may also have potential health beneficial effects. This review focuses on the phytochemical composition of quinoa and amaranth seeds, the antioxidant and anti-inflammatory activities of hydrophilic (e.g. phenolics, betacyanins) and lipophilic (e.g. fatty acids, tocopherols, and carotenoids) nutrients, and how these contribute to the potential health benefits, especially in lowering the risk of the oxidative stress related diseases e.g. cancer, cardiovascular disease, diabetes, and obesity. The gap between current knowledge and future research needs have also been identified.

Indigenous leafy vegetables of Eastern Africa - A source of extraordinary secondary plant metabolites

Indigenous African leafy vegetables vary enormously in their secondary plant metabolites whereat genus and the species have a great impact. In African nightshade (Solanum scabrum), spiderplant (Cleome gynandra), amaranth (Amaranthus cruentus), cowpea (Vigna unguiculata), Ethiopian kale (Brassica carinata) and common kale (Brassica oleracea) the specific secondary metabolite profile was elucidated and gained detailed data about carotenoids, chlorophylls, glucosinolates and phenolic compounds all having an appropriate contribution to health beneficial properties of indigenous African leafy vegetables. Exemplarily, various quercetin glycosides such as quercetin-3-rutinoside occur in high concentrations in African nightshade, spiderplant, and amaranth between ~1400-3300μg/g DW. Additionally the extraordinary hydroxycinnamic acid derivatives such as glucaric isomers and isocitric acid isomers are found especially in amaranth (up to ~1250μg/g DW) and spiderplant (up to 120μg/g DW). Carotenoids concentrations are high in amaranth (up to101.7μg/g DW) and spiderplants (up to 64.7μg/g DW) showing high concentrations of β-carotene, the pro-vitamin A. In contrast to the ubiquitous occurring phenolics and carotenoids, glucosinolates are only present in the Brassicales species Ethiopian kale, common kale and spiderplant characterized by diverse glucosinolate profiles. Generally, the consumption of a variety of these indigenous African leafy vegetables can be recommended to contribute to different benefits such as antioxidant activity, increase pro-vitamin A and anticancerogenic compounds in a healthy diet.

Antioxidant properties and preliminary evaluation of phytochemical composition of different anatomical parts of amaranth

Antioxidant properties of amaranth extracts isolated sequentially by acetone and methanol/water from defatted plant leaves, flowers, stems and seeds were assessed by ABTS(+•), DPPH(•), ORAC and total phenols content (TPC) assays. In addition, antioxidant properties of solid plant material were evaluated by the direct QUENCHER method using the same assays. Leaves and flowers of amaranth as well as their extracts possessed the highest antioxidant activities. Radical scavenging capacity in ABTS(+•) assay for leaves, flowers, stems and seeds evaluated by QUENCHER method were 144.24 ± 2.41, 112.33 ± 7.45, 19.05 ± 1.13 and 21.82 ± 1.06 μmol trolox equivalents in 1 g of dry weight, respectively. On-line HPLC-DPPH(•) assay was used to determine the activity of separated compounds and it was observed that rutin was the main radical scavenger in amaranth extracts. Preliminary screening of extract composition was performed by UPLC/ESI-QTOF-MS and rutin, nicotiflorin, isoquercitrin, 4-hydroxybenzoic and p-coumaric acids were identified by measuring their accurate mass and retention time.

Nutritional Components of Amaranth Seeds and Vegetables: A Review on Composition, Properties, and Uses

 A few decades ago Amaranthus was rediscovered as a most promising plant genus that may provide high-quality protein, unsaturated oil, and various other valuable constituents. Since then research has focused on various Amaranthus spp. and has been rapidly expanding, and a large number of reports have been published. Several review articles focusing on different aspects, such as botanical, agrotechnological, compositional, biological, chemical, and technological properties, as well as applications and health effects, have also been published since then. This comprehensive review is focused on amaranth composition, antioxidant properties, applications, and processing. The composition includes macrocomponets (lipids, proteins, carbohydrates, and dietary fiber) and other important constituents, such as squalene, tocopherols, phenolic compounds, phytates, and vitamins. These aspects of amaranth studies have not been comprehensively reviewed for a long time.

Phytochemical Composition, Antioxidant and Xanthine Oxidase Inhibitory Activities of Amaranthus cruentus L. and Amaranthus hybridus L. Extracts

This paper describes a preliminary assessment of the nutraceutical value of Amaranthus cruentus (A. cruentus) and Amaranthus hybridus (A. hybridus), two food plant species found in Burkina Faso. Hydroacetonic (HAE), methanolic (ME), and aqueous extracts (AE) from the aerial parts were screened for in vitro antioxidant and xanthine oxidase inhibitory activities. Phytochemical analyses revealed the presence of polyphenols, tannins, flavonoids, steroids, terpenoids, saponins and betalains. Hydroacetonic extracts have shown the most diversity for secondary metabolites. The TLC analyses of flavonoids from HAE extracts showed the presence of rutin and other unidentified compounds. The phenolic compound contents of the HAE, ME and AE extracts were determined using the Folin–Ciocalteu method and ranged from 7.55 to 10.18 mg Gallic acid equivalent GAE/100 mg. Tannins, flavonoids, and flavonols ranged from 2.83 to 10.17 mg tannic acid equivalent (TAE)/100 mg, 0.37 to 7.06 mg quercetin equivalent (QE) /100 mg, and 0.09 to 1.31 mg QE/100 mg, respectively. The betacyanin contents were 40.42 and 6.35 mg Amaranthin Equivalent/100 g aerial parts (dry weight) in A. cruentus and A. hybridus, respectively. Free-radical scavenging activity expressed as IC₅₀ (DPPH method) and iron reducing power (FRAP method) ranged from 56 to 423 µg/mL and from 2.26 to 2.56 mmol AAE/g, respectively. Xanthine oxidase inhibitory activities of extracts of A. cruentus and A. hybridus were 3.18% and 38.22%, respectively. The A. hybridus extract showed the best antioxidant and xanthine oxidase inhibition activities. The results indicated that the phytochemical contents of the two species justify their traditional uses as nutraceutical food plants.

Variation of polyphenols and betaines in aerial parts of young, field-grown Amaranthus genotypes

Amaranthus hybridus and Amaranthus mantegazzianus are commonly cultivated and the entire young fresh plants consumed as vegetables in regions of Africa and Asia. A. hybridus and A. mantegazzianus were cultivated at four sites in three climate regions of the world: Santa Rosa, Argentina; Lleida, Spain; and Prague and Olomouc, both in the Czech Republic. The contents of flavonoids (isoquercitrin, rutin, nicotiflorin), hydroxybenzoic acids (protocatechuic acid, 4-hydroxybenzoic acid, vanillic acid), hydroxycinnamic acids (caffeic acid, p-coumaric acid, ferulic acid), hydroxycinnamyl amides (N-trans-feruloyltyramine, N-trans-feruloyl-4-O-methyldopamine), and betaines (glycinebetaine, trigonelline) were determined. The variation in phytochemical content due to species and cultivation site was analyzed utilizing the multivariate statistical methods of principal component analysis (PCA) and graphical model (GM). The Argentinean samples differed from the three other locations due to higher contents of most compounds. The samples from Spain and the Czech Republic differed from each other in the content of the negatively correlated metabolites trigonelline and the flavonoids. The two amaranth species were separated primarily by a higher content of trigonelline and the two hydroxycinnamyl amides in A. mantegazzianus. The GM showed that the quantities of the different analytes within each compound group were intercorrelated except in the case of the betaines. The betaines carried no information on each other that was not given through correlations with other compounds. The hydroxycinnamic acids were a key group of compounds in this analysis as they separated the other groups from each other (i.e., carried information on all of the other groups). This study showed the contents of polyphenols and betaines in the aerial parts of vegetable amaranth to be very dependent on growth conditions, but also revealed that some of the compounds (trigonelline and the two hydroxycinnamyl amides) may be useful as features of a taxonomic classification.