Antioxidant and Antimicrobial Effects of Baby Leaves of Amaranthus tricolor L. Harvested as Vegetable in Correlation with Their Phytochemical Composition

Abstract

Amaranth is used as a spinach replacement; therefore, it is sometimes called Chinese Spinach. So far, the activity of the plant has not been associated with the presence of specific compounds. Three cultivars of Amaranthus tricolor L. were investigated for their antioxidant and antimicrobial activities. The correlation between the bioactivity and metabolite profiles was investigated in order to indicate active compounds in A. tricolor. The phytochemical profile of a total of nine extracts was studied by HPLC-DAD-ESI/HRMS, revealing the presence of 52 compounds. The highest antioxidant activity was noticed in the Red cultivar (0.06 mmol TE/g DE (Trolox Equivalent/Dry Extract Weight) and was related to the presence of amino acids, flavonoids and phenolic acids, as well as individual compounds such as tuberonic acid hexoside. All studied extracts revealed antimicrobial activity. Gram-positive bacteria were more susceptible to N-(carboxyacetyl) phenylalanine, phenylalanine, tuberonic acid and succinic acid and Gram-negative bacteria to dopa, tryptophan, norleucine, tuberonic acid hexoside, quercetin-O-hexoside, luteolin-O-rhamnosylhexoside, luteolin-6-C-hexoside succinic acid, gallic acid-O-hexoside, dihydroxybenzoic acid and hydroxybenzoic acid. Maleic acid showed promising antifungal activity. In summary, A. tricolor is a good source of antioxidant and antimicrobial compounds.

Basella alba L. (Malabar Spinach) as an Abundant Source of Betacyanins: Identification, Stability, and Bioactivity Studies on Natural and Processed Fruit Pigments

“…The results obtained for Atriplex hortensis var. rubra and Amaranthus tricolor were in the range of 0.18–0.24 mmol/g DW and 0.015–0.060 mmol/g DW based on the ABTS test, respectively, and varied depending on the specific plant part.…”

HPLC-Based Metabolomic Analysis and Characterization of Amaranthus cruentus Leaf and Inflorescence Extracts for Their Antidiabetic and Antihypertensive Potential

“…Another distinctive feature of amaranth is the accumulated natural compounds, such as betalains, which give the plant-colored inflorescences, leaves, and stems. The main betalains in amaranth are amaranthin and its epimer isoamaranthin [9]. However, until very recently, the diversity of betalains has become evident [10].…”