PHYTOCHEMICAL SCREENING AND ANTIMICROBIAL EVALUATION OF AERIAL PART OF OCIMUM BASILICUM PLANT USING ETHANOL

This study investigated the phytochemical constituents and antimicrobial activity of the ethanol extract of the aerial part of Ocimum basilicum Linn. (sweet basil). The plant material was collected from Damboa Local Government Area, Borno State, Nigeria, air-dried, pulverized, and extracted using ethanol by maceration. The crude extract yielded 3% of a dark brown, amorphous residue. Qualitative phytochemical screening revealed the presence of flavonoids, cardiac glycosides, terpenoids, and tannins, while alkaloids, saponins, and anthraquinones were absent. Antimicrobial evaluation was carried out using the disc diffusion method against selected clinical isolates, including Bacillus subtilis and Klebsiella pneumoniae. The ethanol extract showed no observable inhibitory activity against any of the tested microorganisms at all concentrations compared with standard antibiotics. These findings suggest that although O. basilicum contains important secondary metabolites of pharmacological interest, the ethanol extract of its aerial parts does not possess significant antimicrobial properties under the conditions tested. The study recommends further investigation using different solvents, plant parts, extract fractions, and advanced analytical techniques to better characterize its bioactive constituents and explore other possible biological activities.