The antimicrobial and phytonutrient profile of Ocimum gratissimum

Many plant-derived compounds have been used as drugs, either in their original or semi-synthetic forms. Plant derived metabolites can also serve as lead compounds, which may be used as templates for the development of new drugs. Therefore, the aim of this study was to evaluate the phytochemical and antimicrobial activities of extract of O. gratissimum leaves on selected clinical pathogenic organisms. The plant materials were obtained through successive extractions using solvents of different polarities such as petroleum ether, ethanol and distilled water. The phytoconstituents were analyzed using standard procedures while antibacterial activities of the extracts were then evaluated by the hole-agar-well diffusion method. The minimum inhibitory concentration of the extract was determined against the isolated microorganism by agar dilution method. The presence of tannins, flavonoids, saponins, glycosides, steroids, triterpenoids and alkaloids in the different leaf extracts was established at varying concentration from the results. The ethanol extract was found to be the most potent, followed by the petroleum ether extract, while aqueous extract was the least potent. Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Candida albican were highly susceptible to the ethanol extracts, since it showed the most susceptible  higher zones of inhibition. The ability of the extracts to inhibit the growth of several bacterial and fungal species is an indication of the broad spectrum antimicrobial potential of leaf extract of O. gratissimum, which suggests the plant as a tool for bioprospecting for antibiotic and antifungal drugs.