An Ethnomedicinal Plant: Antibacterial Activities of Stachys Lavandulifolia Vahl Aqueous Extract against Common Pathogens

Enhancing microbial resistance to antibiotics and their probable side effects leads to the popularity of medicinal plants, so the need for novel antibacterial compounds with plant origin is felt more than ever. The object of the present study was to assess the antibacterial property of Stachys lavandulifolia Vahl aqueous extract (SLVAE) on Escherichia coli O157:H7 (EC), Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA) and Bacillus subtilis (BS). The aqueous extract was obtained using a rotary evaporator. Agar disk and well diffusion methods were used to investigate the antibacterial property of the SLVAE. In the agar disk diffusion test, distilled water was used as a negative control whereas streptomycin, oxytetracycline, gentamicin, difloxacin, chloramphenicol, ampicillin, and amikacin were used as positive controls. Macro broth tube test was accomplished to specified Minimum Inhibitory Concentration (MIC). Statistical comparison among groups means were done through one-way ANOVA followed by Duncan’s post-hoc test. P ≤ 0.01 was considered as significant. Indeed compared with many standard antibiotics, the extract showed the higher antibacterial property. Also SLVAE with 125, 15/62 and 7/81 mg/mL concentrations has prevented the growth of EC, SA/BS and PA, respectively, and with 125, 62/5 and 15/62 mg/mL concentrations has destroyed EC, SA/BS and PA, respectively (p≤0.01). SLVAE had the most antibacterial activity on PA.  In conclusion the obtained results indicated the antibacterial effect of SLVAE on EC, PA, SA, and BS. It seems that this plant can be used for the treatment of some bacterial infections as an antibiotic.