keywords: Antibacterial, alkaloids, flavonoids, Ocimum gratissimum, phytochemicals
The use of Ocimum gratissimum (scent leaf) as food and medicine could be attributed to its phytochemical and antimicrobial properties. This work is aimed at evaluating the phytochemicals and antibacterial activities of Ocimum gratissimum on some selected drug resistant bacteria. The antibacterial activities of the plant potent extracts were tested on the test isolates using Agar-well diffusion techniques. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extracts were determined according to the macro broth dilution technique. Phytochemical analysis of fresh and dried leaf extracts revealed the presence of tannins, alkaloids, flavonoids saponin, and terpeniods. Results obtained revealed that the cold water extracts of the fresh leaves was most potent, inhibiting all isolates with diameter zones of inhibition ranging from 16 to 20 mm, followed by ethanol extract of the dry leaves with zone range of 15 to 18 mm and hot water fresh leaf 11 to 18 mm, but E. coli showed total resistance to the cold water dry leaf extract. The extracts inhibited the growth of the bacterial isolates in a concentration dependent manner with MICs ranging between 50.5–150 mg/ml, while MBC ranged from 12.5–100 mg/ml. The findings from this study seem to provide the in vitro evidence that might justify O. gratissimum as a good candidate medicinal plant for further investigations, and that the active principles of the plant may be more polar in nature.