Nigella sativa (black seed), Syzygium aromaticum (clove), and Commiphora myrrha (myrrh) are examples of medicinal plants that have gained popularity in the last decades due to their high contents of phytochemical constituents and consequently to their potent biological activities. Different extracts of the aforementioned medicinal plants were prepared, using organic solvents acetone and methanol, as well as a water extract; they were evaluated separately for their antibacterial activities against human pathogenic bacteria Staphylococcus aureus, Bacillus subtilis as Gram-positive bacteria and against Gram-negative Escherichia coli, and Pseudomonas aeruginosa. The experiment was carried out using agar well diffusion techniques. Different inhibition effects were observed, which could be mainly attributed to the presence of various chemical constituents. They can be used as such as good precursors for new antibacterial agents. Data from the present study showed that E. coli was the most sensitive bacterial strain, mostly to the clove methanol extract, followed by the acetone extract on Pseudomonas, Bacillus, and Staphylococcus. Black seed and myrrh solvent extracts showed similar activity against Bacillus more than against all other isolates. All aqueous extracts, except myrrh water extract, demonstrated negligible effect on the tested bacteria, indicating moderate activity against all isolates. This variation in the efficacy could be related to the bacterial structure as well as the major phytoconstituents.
IJPRAS
