Phytochemical screening and antimicrobial evaluation of ethanol extract and fractions of the leaf of Terminalia mantaly H. Perrier (Combretaceae)

Abstract

Medicinal plants contain bioactive chemical substances that are active against external invaders such as pathogenic microorganisms. These bioactive chemicals are primarily manufactured by plant for self defense but have been employed in the treatment of infectious diseases that affect humans due to their therapeutic benefits. The aim of this study is to carry out the phytochemical screen and to evaluate the antimicrobial activity of ethanol extract and fractions of Terminalia mantaly leaf. Plant materials were powdered and macerated with ethanol. The crude extract was fractionated with n-hexane, chloroform, ethyl acetate and ethanol successively using column chromatography and silica gel as adsorbent. Qualitative phytochemical screening of basic plant secondary metabolites was carried out using standard procedures. The ethanol plant extract and fractions were reconstituted in dimethylsulphoxide (DMSO) to 200 mg/ml concentration and Agar well Diffusion method was used in the antimicrobial sensitivity screening of clinical strain of enteric microorganisms. Gentamicin and Ketonazole were used as reference standard antibacterial and antifungal drugs respectively. Two-fold dilutions from 200 – 25 mg/ml were done for sensitive extracts and fraction to determine the Minimum Inhibitory Concentration (MIC) and the results obtained were expressed as Mean ± SEM (Standard error of mean). The results of Phytochemical screening revealed the presence of secondary metabolites such as alkaloids, saponins, tannins, flavanoids, steroids and glycosides in the crude extract while the results of the general antimicrobial assay of the extract and fractions showed a comparable potency with gentamicin against Streptococcus pneumonia, Staphylococcus aureus, Escherichia coli and ketoconazole against Aspergillus niger and Candida albicans. The study validated the forkloric uses of this plant as antimicrobial agent scientifically.