Biochemistry of Amaranthus polyphenols and their potential benefits on gut ecosystem: A comprehensive review of the literature.

Abstract Ethnopharmacological relevance The genus Amaranthus is phytonutrients-rich plant distributed worldwide and has been recognized as having medicinal value in traditional use against several diseases and conditions. There are a large amount of research data on the polyphenol profiles of Amaranthus plants and their links with potential benefits against gastrointestinal disorders. Aim of the review This review article aims to provide a comprehensive review of Amaranthus phenolic compounds and their microbial metabolites, as well as the biological and/or pharmacological effects of those compounds/metabolites. Methodology The relevant information about the genus Amaranthus was collected from various sources and databases, including Google Scholar, Google Books, PubMed, Web of Science, Scopus, Science Direct, and other internet sources. The World Flora Online (2021) database was used to verify the scientific names of the plants. Results Comprehensive review of identified compounds in Amaranthus plants revealed the presence of phenolic acids, flavonoids, and coumarins in each part of the plants. The biotransformation by gut microbiota enzymes prominently produces diverse bioactive metabolites that are potentially active than their precursors. Lines of the evidence support the beneficial roles of Amaranthus extracts in several gastrointestinal diseases, particularly with the polar extracts of several plant parts. Dietary fibers in Amaranthus plants also coordinate the alteration of gut microbiota-related metabolisms and may be beneficial to certain gastrointestinal disorders in particular, such as constipation. Conclusions Amaranthus plants are rich in polyphenols and dietary fibers. Several microbial metabolites are biologically active, so alteration of gut microbiota is largely linked to the metabolic feature of the plants. Based on the evidence available to date, several Amaranthus plants containing a combination of phytonutrients, particularly polyphenols and dietary fibers, may be a promising candidate that is of interest to be further developed for use in the treatment of certain gastrointestinal conditions/disorders.