Antibacterial Effects of Aqueous and Ethanolic Extracts of Medicinal Plants Against Pathogenic Strains

Background Medicinal plants have been known since ancient times, as an anti-microbial spectrum against microorganisms. The production of secondary plant metabolites creates an important source of bactericide and various pharmaceutical drugs. In this study, the antimicrobial activity of aqueous and ethanolic extracts of the leaves of Glycyrrhiza glabra, Mentha spicata and Rosmarinus officinalis was evaluated against resistant strains of Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. Methods Antimicrobial effects of plants were investigated using a strain of Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus, at the standard bacterium laboratory of the Veterinary Department, University of Islamic Azad, Tehran, Iran. Results Minimum inhibitory concentration (MIC) values ranged from 6.25 to 100.0 ppm, while Minimum bactericidal concentration (MBC) ranged from 12.5 to 200 ppm. The ethanol extract of Glycyrrhiza glabra had the lowest MIC (6.25 ppm), while the ethanol extract of Rosmarinus officinalis and Mentha spicata had the highest MIC (100 ppm), respectively. The MBC of the ethanolic extract of G. glabra, with the highest bacteria strains, was valuable against the lowest (12.5 PPM). The MBC of the ethanolic extract of G. glabra was valuable against the lowest bacteria strains. Conclusions Our findings showed good antibacterial activity for G. glabra extract that can be utilized as a treatment for infections, caused by P. aeruginosa, E. coli and S. aureus.