Examining the antibacterial activity of Artemisia dracunculus L. extracts using different methods of extraction

The status of medicinal plants in Iranian traditional medicine and rich existence of herbal sources and current problems in curing infections, on the other hand led the scientists to study medicinal plants more accurately. Tarragon (Artemisia dracunculus L.) is a herbaceous plant from Asteraceae family, available in planted and farming forms in Iran. This study aimed to examine the antibacterial activity of Artemisia dracunculus L. in various extraction methods. The Maceration and Soxhlet methods were used to Methanolic extract of Artemisia dracunculus L. and the antibacterial effect of extracts was conducted in various concentrations on Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa microorganisms by Disk diffusion, Well Diffusion, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) methods. The results indicated that both extracts obtained by Maceration and Soxhlet methods had antibacterial effects only on two gram-positive bacteria including Staphylococcus aureus and Bacillus subtilis. Both gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa, were resistant to the extracts in all concentrations. In the current study, the antibacterial properties of two methanolic extract which obtaiened by maceration and soxhlet methods were examined. According to results, the extract gained by maceration method showed higher antibacterial properties in copmparision with soxhlet method. The maceration obtained extract showed antibacterial properties on gram-positives bacteria in all applied concentration while in soxhlet extract that was only in 200 mg/ml. Gramnegative bacteria had no sensetivity to both extracts in all applied concentrations. The higher sensitivity in gram-positive bacteria to the extracts may result from the fact that gram-negative bacteria contain an outer membrane and a periplasmic space that are not seen in gram-positive bacteria. The outer membrane of gram-negative bacteria is known as a barrier against various antibiotic molecules penetration. On the other hand, this membrane prevents hydrophilic penetration into the bacteria. The periplasmic space contains many enzymes enable it to dissect outer molecules that come from the outer space.