Evaluation of Anti-Bacterial Activity of Lavandula angustifalia Alcoholic and Aquatic Extracts on some Pathogenic Bacteria.

Lavender with the scientific name Lavadul angustifelia belongs to the mint family, and the extract and essence of this plant are widely used in traditional medicine. This study was conducted with the aim of investigating the antibacterial effects of alcoholic and aqueous extracts of lavender on some pathogenic bacteria. First, alcoholic and aqueous extracts of lavender were prepared by Soxhlet method, and then concentrations of 100 to 0.39% of this extract were prepared and their effect on standard strains of bacteria Bacillus subtilis, Streptococcus mutans, Listeria monocytogenes, Yersinia enterocolitica and Salmonella enteritidis determined by well diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts on the studied bacteria were measured by the micro-titer plate method with the reduction of resazurin dye. The results showed that the alcoholic and aqueous extracts of Lavander have a significant inhibitory effect on all five tested bacteria. By increasing the concentration of the extracts, their effect on the studied bacteria increased. Also, both extracts (aqueous and alcoholic) had a greater effect on gram-positive bacteria, so that both Lavender extracts showed the greatest effect on Bacillus subtilis and the least effect on Salmonella enteritidis. The inhibitory and lethality effects of the alcoholic extract was higher than that of the aqueous extract. Alcoholic and aqueous extracts of Lavandula angustifalia have significant inhibitory effects on the growth of pathogenic bacteria, especially gram-positive bacteria, so they can be used to against diseases caused by these bacteria.