A comparison of antibacterial activity of aqueous, Ethanol, and Methanol extracts of olive in two polluted and clean regions

Olive is medicinal which is nowadays grown as an ornamental plant in cities. Given the tendency of people to use herbs, it appears essential to explore whether the plants grown in cities have the same properties as the naturally grown plants or some of their traits are changed due to the pollution of the air in the cities. The antimicrobial effect of olive leaf extracts on the activity of two gram-positive (i.e. Bacillus subtilis and Staphylococcus areous) and gram-negative bacterium (i.e. Pseudomonas aeroginosa and Escherichia coli) was explored under laboratory condition. Olive Olea europaea leaves were collected from a clean (district 22) and polluted (district 6 and 7) areas. Different aqueous, ethanol, and methanol concentrations (10, 20, and 50%) were prepared. To compare the antimicrobial effects of extracts, broad-spectrum antibiotics ciprofloxacin disks (CP) and Ceftizoxime (CT) were used. The analyses indicated that there was a significant difference in the activity of olive leave in clean and polluted areas and different methods of extraction. The highest amount of antimicrobial properties was observed in ethanol extracts. These extracts had antibacterial effect on Escherichia coli, Pseudomonas aeroginosa, and Bacillus subtilis, in clean area. Thereby, people should be informed that the olives planted in the polluted regions of Tehran (street, park, or houses) are merely ornamental and do not have medicinal value.