Antibacterial Effects of Essential Oil of Hedge Nettle and Purslane Plants on Staphylococcus aureus: In Vitro and Animal Model

Antibacterial Effects of Essential Oil of Hedge Nettle and Purslane Plants on Staphylococcus aureus: In Vitro and Animal Model
Nader Kazemi,^1,* Zahra Asadi,²
1. Department of Microbiology, Biology Research Center, Zanjan Branch, Islamic Azad University, Zanjan, Iran
2. Department of Microbiology, Biology Research Center, Zanjan Branch, Islamic Azad University, Zanjan, Iran
Introduction: Infectious diseases are one of the most common diseases around the world which impose enormous financial burden on society. Staphylococcus aureus is an important causes of nosocomial infections and multi drug resistance. Although synthetic antibiotics have been able to play an important role in treatment of infectious diseases in past decades, however problems related to microbial resistance of antibiotics have caused that the medical plants to be considered as an alternative. On the other hand, medical properties of the extracts and essential oils against microbial as well as non microbial diseases have been known since ancient times and many studies have been performed on medical properties of the different plant species and their essential oil or extracts effects on microorganisms.
Methods: In this study, essential oil was prepared from dried leaves of the Stachys schtschegleevi and Portulaca oleracea, then anti-bacterial activities of the essential oil for Staphylococcus aureus was experimented, first by the method of well diffusion in agar, and later the amount of the MIC and MBC of the essential oils were measured by broth dilution method. In animal model study, first 5×105 CFU/ml of bacteria was intraperitoneally injected and after 24 hours, 0.5ml (as MBC concentration of each the essences) of essential oils, to female BALB/c mice was intrapertioneally injected. Then, the counting of bacterial clonies in spleen were determined with cultivation on Mueller Hinton agar after 7 days as the standard protocol.
Results: The experiment results concerning the determination of growth inhibition diameter in agar showed that the maximum of growth inhibition diameter is related to the essential oil of Stachys schtschegleevi (30 mm), and the minimum of growth inhibition diameter is related to essential oil of Portulaca oleracea (10 mm) at the highest concentration (400 mg/ml). The results of broth microdilution method on Staphylococcus aureus showed that the amounts of the MIC and MBC in essential oils of the Stachys schtschegleevi and Portulaca oleracea were the same and equal to 3.90 mg/ml and 7.181 mg/ml. any antimicrobial activity. In conditions of in vivo, spleen supernatant cultivation, the average number of bacteria for Stachys schtschegleevi and Portulaca oleracea essential oil were 2×102 CFU/ml and 6×102 CFU/ml respectively. These results showed significantly decrease in number of bacteria in all experimental groups (p˂0.5) compared to control group.
Conclusion: In general, the results of evaluations in experimental conditions and the animal model showed that the essential oils of Stachys schtschegleevi and Portulaca oleracea have the effective antibacterial activity against mentioned bacteria and can be useful to treatment of nosocomial infections.
Keywords: Antimicrobial, Essential oil, Portulaca oleracea, Stachys schtschegleevi, Staphylococcus aureus