Betalains are nitrogen-containing plant pigments that can be red-violet (betacyanins) or yellow-orange (betaxanthins), currently employed as natural colourants in the food and cosmetic sectors. Betalains exhibit antimicrobial activity against a broad spectrum of microbes including multidrug-resistant bacteria, as well as single-species and dual-species biofilm-producing bacteria, which is highly significant given the current antimicrobial resistance issue reported by The World Health Organization. Research demonstrating antiviral activity against dengue virus, in silico studies including SARS-CoV-2, and anti-fungal effects of betalains highlight the diversity of their antimicrobial properties. Though limited in vivo studies have been conducted, antimalarial and anti-infective activities of betacyanin have been observed in living infection models. Cellular mechanisms of antimicrobial activity of betalains are yet unknown; however existing research has laid the framework for a potentially novel antimicrobial agent. This review covers an overview of betalains as antimicrobial agents and discussions to fully exploit their potential as therapeutic agents to treat infectious diseases.
Matched MeSH terms: Betalains/pharmacology; Betalains/therapeutic use
Phytochemicals belonging to the group’s phenols, terpenes, betalains, organosulfides, indoles and protein inhibitors are important components in fruits, vegetables, legumes, whole grains and nuts that have health promoting benefits and a variety of applications in food and pharmaceutical industries. Initially only a few of these important phytochemicals are produced commercially by chemical synthesis. However, recent developments in the field of biotechnology have provided metabolic engineering strategies that use microorganisms as cell factories for high production of these products. This review will discuss the general biosynthetic pathways, metabolic engineering and optimization strategies of functional phytochemicals that have received a lot of attention from investigators.
Alternanthera sessilis (red) (ASR) is an edible herbal plant with many beneficial health effects. This study aimed to investigate the antioxidant components and antioxidant activities of the edible leaves and stems of ASR extracted using solvent of varying polarities namely water, ethanol, ethyl acetate and hexane. ASR leaf extracts showed higher in both antioxidant components and activities than the stem extracts. Among the antioxidant components, the ethanol leaf extract showed higher phenolic (77.29 ± 1.02 mg GAE/g extract) content while the ethyl acetate leaf extract was rich in flavonoids (157.44 ± 10.19 mg RE/g extract), carotenoids (782.97 ± 10.78 mg BE/g extract) and betalains (betanin: 67.08 ± 0.49 mg/g extract; amaranthin: 93.94 ± 0.68 mg/g extract and betaxanthin: 53.92 ± 0.88 mg/g extract). Nevertheless, the ethanol leaf extract showed the highest DPPH radical scavenging activity and ABTS radical cation scavenging activity. It also exhibited highest ferric reducing activity among all the extracts. Four polyphenolic compounds from ASR leaf, namely ferulic acid, rutin, quercetin and apigenin, were identified and quantified using ultra high performance liquid chromatography. The existence of these compounds was further verified using tandem mass spectrometry. These current results indicate that ASR leaf particularly the ethanol extract has the potential to be exploited as a source of natural antioxidants.