Abstract

Background and Objective: It has been proved that plant essential oils have antimicrobial effects. Stachys Lavandulifolia Vachl is a medicinal plant growing wild in many parts of Iran, and is used as a brewed drink to treat some diseases.

Material and Methods: Aerial parts of Stachys lavandulifolia Vachl at flowering were collected from the Sabalan mountainous   area of Ardabil and its essential oil was extracted using a Clevenger-type apparatus. A GC/MS machine was used to identify the chemical constituents of this Essential oil. We used microdilution method to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Essential oil against Listeria Monocytogenes ATCC19118 bacteria.

Result: Sixteen chemical compounds were identified in this essential oil. Of these, γ-terpinene (28%), Phenol (18.16%), Myrcene (17.87%), and α-Pinen (12.7%) were the major ones. The MIC and MBC of the essential oil for Listeria Monocytogenes bacteria were 600 and 2400 ppm, respectively.

Conclusion: Results showed that the Monoterpene and Sesquiterpene groups are the main constituents of this essential oil having bactericidal effects against Listeria Monocytogenes bacteria.

Keywords: Essential Oil, Stachys Lavandulifolia, Listeria Monocytogenes

ABSTRACT

         Background and Objective: Although antibiotics are commonly used for treatment of infectious diseases, these treatments are often associated with several problems such as unwanted side effects and resistance to antibiotics. The aim of this study was to evaluate the antibacterial effect of aqueous and alcoholic extracts of Nasturtium officinale on Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Listeria monocytogenes.

          Methods: All experiments were performed using the well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the aqueous and alcoholic extracts of N. officinale against the pathogenic bacteria studied were determined by microdilution method.

         Results: In the well diffusion method, S. aureus and L. monocytogenes were the most sensitive bacteria with MIC of 8 μg/ml, while E. coli and S. typhimurium were the most resistant bacteria to the aqueous and alcoholic extracts. In addition, the inhibitory activity of the alcoholic and aqueous extracts of N. officinale was higher against gram-positive bacteria compared to gram-negatives. The lowest MIC (6.25 μg/ml) and MBC (12.5 μg/ml) of the plant extract were against S. aureus.

          Conclusion: The aqueous and alcoholic extracts of N. officinale affect the growth of gram-positive bacteria (S. aureus and L. monocytogenes) but not the gram-negatives (S. typhimurium and E. coli). These extract could be used for treatment of infections.

        Keywords: Nasturtium Officinale, Aqueous Extract, Alcoholic Extract, Antibacterial Effect.

ABSTRACT
         Background and Objectives: Due to their antimicrobial, anticancer and antioxidant properties (due to the presence of free radical scavengers), essential oils and extracts of medicinal plants are of great importance as natural medicinal compounds in public health, treatment of diseases, and protection of raw and processed foods. 
           Methods: Chemical composition and content of essential oil of Thymus kotschyanus was determined by gas chromatography–mass spectrometry. The amount of phenolic and flavonoid compounds in the essential oil was determined by spectrophotometry using gallic acid and quercetin as standards. The antioxidant properties of the essential oil were evaluated by the DPPH method.
         Results: The analysis of essential oil with gas chromatography–mass spectrometry showed that thymol (51.1%), p-cymene (13.78%) and α-pinene (7.42%) are the main components. The amount of phenolic compounds was 82 ± 6.43 μg gallic acid/ml essential oil, while the flavonoid content was 30.79 ± 0.5 μg quercetin/ml essential oil. In terms of antioxidant activity, the IC50 value of T. kotschyanus essential oil was determined as 32.35 μg/ml, which is weaker than synthetic antioxidant butylated hydroxytoluen.
          Conclusion: The results indicate that the essential oil of T. kotschyanus has good antioxidant activity and can be used in combination with other preservatives to protect food against a variety of oxidative systems.
            Keywords: Essential Oil, Antioxidant Activity, Thymus Kotschyanus.