Phytochemical analysis and antimicrobial potential of Amaranthus viridis L.

Abstract

The increasing emergence of antimicrobial resistance has intensified the search for alternative, plant based therapeutic agents. Amaranthus viridis is traditionally used in folk medicine and is reported to possess diverse bioactive compounds; however, its phytochemical composition and antimicrobial efficacy require further scientific validation. The present study aimed to analyze the phytochemical constituents of Amaranthus viridis L., and to evaluate the antibacterial and antifungal potential of its crude ethanolic extract and solvent fractions. The whole plant of A. viridis was extracted using ethanol and fractionated into n-hexane, ethyl acetate, chloroform and aqueous fractions. Phytochemical profiling was performed using gas chromatography mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR). Antibacterial and antifungal activities were assessed using the agar well diffusion method against selected gram positive and gram negative bacterial strains and pathogenic fungi at three concentrations (6, 9 and 12μg/mL). All experiments were conducted in triplicate. GC-MS analysis revealed the presence of several bioactive compounds, including fatty acids, esters, sterols, and other secondary metabolites, while FTIR analysis confirmed diverse functional groups such as alcohols, phenols, aldehyde, amides, and carboxylic acids. Among the tested samples ethyl acetate and n-hexane fractions exhibited notably higher antibacterial and antifungal activities compared to ethanolic, chloroform, and aqueous fractions, showing a concentration dependent response against most tested microorganisms. The findings demonstrate that Amaranthus viridis L. is a promising source of bioactive compounds with significant antimicrobial potential. The activity of non-polar and semi-polar fractions suggests that these extracts may contain key antimicrobial constituents. Further studies focusing on isolation, characterization, and mechanistic evaluation of these compounds are recommended for potential pharmaceutical applications.