Abstract

The present study assesses the antibacterial activities of whole plant extracts of Ocimum americanum Linn. tested against pathogenic microorganisms. Preparation of different extracts viz., chloroform, petroleum ether, ethyl acetate and ethanol through cold maceration extraction method. Various extracts were investigated against strains of Streptococci, Staphylococci, Escherichia coli and Salmonella typhi by agar well diffusion method. Phytochemicals and functional groups were observed by gas chromatographymass spectrometry. Chloroform extract of Ocimum americanum showed significant antibacterial activity against all tested pathogens in the agar well diffusion method in which Salmonella typhi (18.42±0.85) mm was observed high zone of inhibition, whereas the lowest inhibition was observed in ethyl acetate extract against Streptococci (8.32±0.20) mm. Phytochemical studies reveal that the whole plant contains alkaloids, terpenoids, fixed oils and flavonoids as phytoconstituents. The gas chromatography-mass spectrometry method screened one bioactive phytochemical in the chloroform extract and two bioactive phytochemicals in the petroleum ether extract of Ocimum americanum. The recognition of phytochemical compounds is based on the peak area, retention time molecular weight, molecular formula, mass spectrometric fragment ions and pharmacological actions. Therefore, chloroform and ethyl acetate extracts of Ocimum americanum could act as an antibacterial agent and further studies are recommended for the isolation of compounds and toxicological studies.