Amaranthus tricolor (red amaranth), an indigenous source of nutrients, minerals, amino acids, phytochemicals, and assessment of its antibacterial activity

Abstract

Amaranthus tricolor (red amaranth) is an important member of the Amaranthus species ubiquitously cultivated worldwide for its valuable constituents. In this study, the determination of important nutrients, minerals, amino acids, phytochemicals, carotenes, antiradical activity, and antibacterial activity of the entire part of the red amaranth plant was performed. The analysis of the nutritional composition of the whole part of red amaranth shows that there was an appreciable quantity of protein (26.60 ± 0.42%), fat (4.49 ± 0.30%), fiber (6.67 ± 0.33%), and carbohydrate (39.80 ± 0.15%). Potassium (1080.02 ± 32.51 mg/100g dry weight) was found as a major trace element among others (Na, Ca, and Iron). Overall seventeen amino acids were identified and the most abundant amino acid in red amaranth was glutamic acid (23.61 ± 0.16 mg/g). However, lysine (14.32 ± 0.20 mg/g) was found to be higher than each of the essential amino acids in red amaranth. The value of total phenolic content, total flavonoid content, and total antioxidant activity in the methanolic extract of red amaranth was 30.27 ± 1.98 mg gallic acid equivalent/g, 16.75 ± 0.82 mg quercetin equivalent/g and 62.91 ± 3.35 mg ascorbic acid equivalent/g extract respectively. The IC 50 value for DPPH radical scavenging activity was 730.93 μg/mL. The selected vegetable also contained an appreciable amount of carotenes (15.37 ± 0.27 mg/100g). Plant extract had a modest extent of bacterial growth inhibition activity. Thus, red amaranth is a wonderful source of nutrients, a natural antiradical, and has other bioactive compounds that should be in a regular dietary item and useful for nutraceuticals. • Chemical composition (proximate contents, mineral contents, amino acids), phytochemical composition, and antibacterial activity of Amaranthus tricolor were determined. • Red amaranth was a wonderful source of protein, fiber, fat, minerals, and amino acids. • An appreciable content of phenolic acids, flavonoids, and carotenes that contributes to having a potent antiradical activity. • FTIR analysis shows the presence of hydroxyl group and carbonyl group in dry powder and methanolic extract. • Plant extract had a bacterial growth inhibition activity.