Umakanta Sarker

Response of nutrients, minerals, antioxidant leaf pigments, vitamins, polyphenol, flavonoid and antioxidant activity in selected vegetable amaranth under four soil water content

Four selected vegetable amaranths were grown under four soil water content to evaluate their response in nutrients, minerals, antioxidant leaf pigments, vitamins, polyphenol, flavonoid and total antioxidant activity (TAC). Vegetable amaranth was significantly affected by variety, soil water content and variety × soil water content interactions for all the traits studied. Increase in water stress, resulted in significant changes in proximate compositions, minerals (macro and micro), leaf pigments, vitamin, total polyphenol content (TPC), and total flavonoid content (TFC) of vegetable amaranth. Accessions VA14 and VA16 performed better for all the traits studied. Correlation study revealed a strong antioxidant scavenging activity of leaf pigments, ascorbic acid, TPC and TFC. Vegetable amaranth can tolerate soil water stress without compromising the high quality of the final product in terms of nutrients and antioxidant profiles. Therefore, it could be a promising alternative crop in semi-arid and dry areas and also during dry seasons.

Phenotypic divergence in vegetable amaranth for total antioxidant capacity, antioxidant profile, dietary fiber, nutritional and agronomic traits

ABSTRACT A lot of variations in vegetable amaranth germplasm have been observed in Bangladesh. It has been used as a cheap source of antioxidants, nutrients, protein, and dietary fiber. But no efforts had not been taken to know the status of antioxidant content, polyphenol, flavonoid, antioxidant vitamins and minerals, dietary fiber, nutritional and agronomic traits. In this study, Forty-three vegetable amaranth genotypes were evaluated to determine the status of total antioxidant content, polyphenol, flavonoid, antioxidant vitamins and minerals, dietary fiber, nutritional and agronomic traits and the magnitude of genetic diversity based on the contribution of those traits for meaningful grouping and proper utilization in future breeding program. The experiment was carried out in an open experimental field at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh in a randomized complete block design with three replications. Multivariate (Principal component and cluster) analysis was done using numerical taxonomic techniques of Sneath, & Sokal. Four principal components contributed 98.61% of the variation. Biological yield and total antioxidant content was strongly associated with their related all agronomic traits. Total flavonoid content had a higher contribution to total antioxidant capacity compared to vitamin and mineral antioxidants. Contribution of antioxidant profile and agronomic traits was the highest in diversity of vegetable amaranth. Both high and low yielding genotypes had a high antioxidant profile. Therefore, high yielding genotypes (From cluster VI) could be used directly as high antioxidant profile varieties and low yielding genotypes as a source of donor parents in hybridization program. Cluster analysis grouped the genotypes into six clusters. The diverse genotypes in different clusters were identified. Genotypes with desirable genes of one cluster hybridized with promising genotypes of other diverge clusters could facilitate the accumulation of favorable genes in hybrids. Abbreviations: PCA: principal component analysis; PC: principal component; dw: dry weight; TFC: total flavonoid content; TAC: total antioxidant capacity; TPC: total polyphenol content; K: potassium; Ca: calcium; Mg: magnesium; Fe: iron; Mn: manganese; Cu: copper; Zn: zinc

Genotypic diversity in vegetable amaranth for antioxidant, nutrient and agronomic traits

In this investigation, magnitude of genetic divergence was studied in 25 vegetable amaranth using D2 statistics. The genotypes were grouped into 5 clusters with the highest number of genotypes (10) in cluster V. High inter-cluster distance indicated that genotypes of cluster III were far diverged from the genotypes in cluster I, II and IV, respectively. The PCA indicated prominent contribution of protein, foliage yield, leaf area and Zn content towards total divergence. Cluster I and Cluster III could be considered for excellent antioxidant and nutrients and high foliage yield. Cluster II for nutrients, cluster IV for antioxidant and nutrients and cluster V for antioxidant, nutrients, and foliage yield. Based on inter-cluster distance, intra-cluster and scatter diagram, the genotypes AA28, AA15, AA19, AA26, AA9 and AA17 would be potential genotypes for generating transgressive segregants.

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.

Augmentation of leaf color parameters, pigments, vitamins, phenolic acids, flavonoids and antioxidant activity in selected Amaranthus tricolor under s alinity 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.

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

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.

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

BackgroundBioactive 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.ResultsThe 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.ConclusionsIn 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.