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

Abstract

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.

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

“…Ten ml acetone (80%) was mixed with 0.5 g leaves (fresh) and ground thoroughly. After centrifugation of the extract for 3–4 min at 10,000×g, the supernatant was removed and the volumetric flask was marked at the final volume of 20 ml [ 22 , 47 ]. The optical density was measured with a spectrophotometer (Hitachi, Japan) at 480 and 510 nm.…”

“…Flavonols, flavanols, flavones, and flavanones in the leaf sample were estimated using a Shimadzu SCL10Avp (Kyoto, Japan) HPLC equipped with a detector, binary pump, and degasser following the method of Sarker and oba [ 47 , 49 ]. Flavonols, flavanols, flavones, and flavanones were separated using a column (STR ODS-II, 150 × 4.6 mm I.D., Kyoto, Japan).…”

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

“…Diphenyl-picrylhydrazyl (DPPH) radical degradation method (37,38) was used to estimate the antioxidant activity. We added 1 ml DPPH solution (250 µM) to 10 µl extract (in triplicate) in a test tube.…”

Characterization of Maize Near-Isogenic Lines With Enhanced Flavonoid Expression to Be Used as Tools in Diet-Health Complexity

“…These compounds are capable of interfering with electron-transfer reaction pathways to scavenge free radicals ( Sarker and Oba, 2019b , 2020b ; Sarker et al, 2020a ), making them promising candidates to counteract inflammation-associated chronic diseases. Though the health-promoting effects of phenolic compounds and flavonoids are well known ( Sarker and Oba, 2020c , d , e ; Sarker et al, 2020b ), clinical studies using purified phytochemicals have yielded conflicting results ( Liu, 2004 ; Vezza et al, 2016 ). For example, a study of more than 11,000 male physicians taking 50 mg β-carotene supplements daily for over 11 years showed no significant changes in terms of CVD incidence as compared to a placebo-receiving group ( Hennekens et al, 1996 ).…”