Phytochemical analysis and antibacterial efficacy of Amaranthus tricolor (L) methanolic leaf extract against clinical isolates of urinary tract pathogens

Urinary tract infections (UTI) are the most common form of bacterial infections, affecting people throughout their lifespan. The present study was designed to evaluate the antibacterial activity of Amaranthus tricolor leaf extract and its phytoconstituents against clinical isolates of urinary tract infections. In the present study, the leaf extract of A. tricolor was prepared by cold maceration using methanol. The preliminary phytochemical screening performed indicated the presence of carbohydrates, aminoacids, proteins, steroids, alkaloids, glycosides, flavonoids and tannins. Clinical isolates of urinary tract pathogens such as Staphylococcus saprophyticus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Proteus vulgaris were used for the study. The antibacterial property was determined by agar well diffusion method and minimum inhibitory concentration (MIC) were determined for crude A. tricolor leaf methanolic extract by resazurin microtitre plate assay method. The results indicate that the methanolic leaf extract of A. tricolor has a notable antibacterial activity against tested microorganisms. The maximum antibacterial activity was observed against E. coli (17.7±0.57 mm). A moderate activity was observed against P. vulgaris (16.6±0.57 mm) and minimum activity against E. faecalis (13.3±1.15mm) with respect to that of zone diameter exhibited by the organisms. The minimum inhibitory concentration was ranged from 5.0 to 0.36 mg/ml. The A. tricolor leaf extract was found to contain some bioactive compounds with pronounced antibacterial activity, however further phytochemical studies and their characterization will be needed to isolate the active constituents and evaluate the antimicrobial activities against a wider range of microbial pathogens.