Nazanin Fathi ^1,2, Feridoun Parnia¹ , Golnaz Rashidi ³, Masume Sattar ⁴, Elnaz Maleki Dizaj ^5,6,7,8,*

¹ Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran

² Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

³ Department of Immunology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

⁴ Islamic Azad University, Urmia branch, Urmia, Iran

⁵ East Azerbaijan Blood Transfusion Organization, Tabriz, Iran

⁶ Islamic Azad University, Bonab branch, Bonab, Iran

⁷ Dental and Periodontal Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

⁸ Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran

*Correspondence:

Elnaz Maleki Dizaj, East Azerbaijan Blood Transfusion Organization, Tabriz, Iran, Dental and Periodontal Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

Tel: +98 (41) 33353162, E-mail: emd1990biologist@yahoo.com

Abstract

Nowadays, traditional medicine is advanced universally as an significant source for health care of the world’s population. In the current study, we tested the antibacterial activity of 3 essential oils (Rosemary oil, Eucalyptus radiata oil, Cinnamon bark oil ) against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). An antimicrobial test based on minimum inhibitory concentration (MIC) was performed to assess the essential oils antimicrobial efficiency. Among 3 essential oils, cinnamon bark oil, showed the lowest MIC and rosemary oil had high MIC. The finding also showed that E. coli was least susceptible to 3 essential oils in this study. This study showed that the tested essential oils can be used as an optimistic antibacterial agent against the selected microorganisms.

Keywords: Essential oils, Traditional medicine, Antibacterial activity

Introduction

According to reports, essential oils are recognized to show antimicrobial action against different types of bacteria. It has been reported and confirmed that medicinal plant’s essential oils can be used for different infections especially for respiratory tract infections and colds. Traditionally, inhalation of these essential oils has been used to treat bronchitis or sinusitis [1-4]. Recently, the progress in sciences has presented new therapeutic ideas for with decreased toxicity and improved efficacy [5-8]. Development of medicinal plant- based therapy may gain more and more effective outcomes with controlling dose and toxicity.

1. aureus is a main human pathogen that causes a wide variety of clinical appearances. It is a Gram-positive, round shaped bacterium that frequently found in the upper respiratory tract and on the skin. This bacteria does not generally cause infection on healthy skin; but, if it is permitted to enter the bloodstream or internal tissues, it may cause a variety of potentially serious infections [9-12].

Edwards-Jones et al tested the antimicrobial effect of some essential oils against S. aureus. Based on their results a combination of geranium and tea tree oil was most active against the methicillin-sensitive S. aureus (Oxford strain). They suggested that the tested essential oils and essential oil vapours can be useful as antibacterial agents and for use in the treatment of MRSA infection [13].

1. coli is a Gram-negative bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms. Some classes of E. colican cause diarrhea, while others cause urinary tract infections, respiratory infection or other diseases [14-17]. Burt et al quantified the antibacterial possessions of five essential oils on a non-toxigenic strain of E. coli O157:H7 at three different temperatures. Their data showed that oregano and light thyme essential oils, especially once improved by agar stabilizer, showed an effective outcome in reducing the number or preventing the growth of E. coli O157:H7 in foods [18].

The current work was aimed to evaluate the antimicrobial activities of 3 essential oils including rosemary oil, eucalyptus radiata oil, cinnamon bark oil against S. aureus and E. coli using MIC test.

Material and methods

The essential oils were purchased from Royca compony, Iran, Thran. Mueller Hinton agar, Mueller Hinton Broth, and nutrient dextrose agar were supplied from Merck Chemicals compony. (Germany).

Bacterial strains

The microorganisms used in this study (Staphylococcus aureus PTCC 1112, Escherichia coli PTCC 1338) were obtained from Iran’s Biotechnology Institute of Scientific and Technical Research (Tehran, Iran).

Inoculum preparation method

The standard bacteria activated firstly and then the selected bacteria were cultured in agar media. Transferring a single colony from the stock into Mueller Hinton Broth and its nightly incubation (at 37°C) were the next steps. In the final phase, we needed to obtain 0.5 McFarland standard turbidity. So, to this end the cells were centrifugated, washed and re-suspended in saline solution.

Determination of MICs

MIC determination was performed by broth microtiter method according CLSI protocol. For detecting the MICs the sterile 96-well microtiter plates (Greiner, Germany) by broth microdilution method was used. Two fold serial dilution method was used to prepare essential oils serial dilutions. In the next step, 100 μl of essential oils diluted solutions was moved into microtiter plates, and then 20 µl of standardized microorganism suspensions was added and incubated at 37 °C for 24 h. Finally, turbidity of wells was measured spectrophotometrically (Ultrospec 2000, Pharmacia Biotech, UK) at the wave length of 620 nm. Each test was done in triplicate. All actions were performed under sterile situations.

Results

MIC results

Based on the MIC tests, among 3 essential oils, cinnamon bark, showed the lowest MIC and Eucalyptus radiata oil had high MIC. The finding also showed that E. coli was least susceptible to 3 essential oils in this study. The results for MICs are collected in Table 1.

Table 1. The results for MICs (µg/ml).

Discussion

According to MIC values, the essential oil containing aldehyde (cinnamon bark oil ) were the most active, followed by that containing alcohol components (eucalyptus radiata oil,). The analysis of cinnamon bark oil by Singh et al showed the presence of 13 components that cinnamaldehyde was found as the major component [19]. A main component of eucalyptus oil in percentage weight was 1,8-cineole, however a main bioactive component was reported to be α-terpineol with eight-fold higher activity than 1,8-cineole against S. aureus in a work by Shigeharu Inouye et al. rosemary oil is reported to contain numerous components with similar percentage however camphor was supposed to be a main bioactive component [2].

Several reports have shown that the Gram-positive bacteria are more susceptible to essential oils than Gram-negative bacteria. The obtained results in this study also displayed that E. coli was least susceptible to 3 essential oils. This outcome can be related to the presence of an outer membrane in Gram-negative bacteria, that influenced hydrophilic polysaccharide chains as a wall to hydrophobic essential oils [2, 20, 21].

Conclusion

An antimicrobial test based on minimum inhibitory concentration (MIC) was performed to assess the essential oils antimicrobial efficiency. It is concluded that the tested essential oils can be used as an optimistic antibacterial agent against the selected microorganisms.

References

1. Fathi, N., E. Ahmadian, S. Shahi, L. Roshangar, H. Khan, M. Kouhsoltani, S.M. Dizaj, and S. Sharifi, Role of vitamin D and vitamin D receptor (VDR) in oral cancer. Biomedicine & Pharmacotherapy, 2019; 109: 391-401.
2. Inouye, S., T. Takizawa, and H. Yamaguchi, Antibacterial activity of essential oils and their major constituents against respiratory tract pathogens by gaseous contact. Journal of antimicrobial chemotherapy, 2001; 47: 565-573.
3. Nahaei, M.R., P. Rahbarfam, M. Kalajahi, S.M. Dizaj, and F. Lotfipour, Antibacterial Activity of Anti-Aphthous Spray and Oral Drop: Two Thymus Commercial Products. Pharmaceutical Sciences, 2017; 23: 166.
4. Anaraki, M.R., A. Jangjoo, F. Alimoradi, S.M. Dizaj, and F. Lotfipour, Comparison of Antifungal Properties of Acrylic Resin Reinforced with ZnO and Ag Nanoparticles. Pharmaceutical Sciences, 2017; 23: 207-214.
5. Zununi Vahed, S., N. Fathi, M. Samiei, S. Maleki Dizaj, and S. Sharifi, Targeted cancer drug delivery with aptamer-functionalized polymeric nanoparticles. Journal of drug targeting, 2018: 1-22.
6. Fathi, N., G. Rashdi, and S. Sharifi, STAT3 and apoptosis challenges in cancer. International Journal of Biological Macromolecules, 2018.
7. Ghotaslou, R., S. Sharifi, M.T. Akhi, and M.H. Soroush, Epidemiology, clinical features, and laboratory detection of Mycoplasma pneumoniae infection in East Azerbaijan, Iran. Turkish Journal of Medical Sciences, 2013; 43: 521-524.
8. Haghshenas, B., Y. Nami, M. Haghshenas, A. Barzegari, S. Sharifi, D. Radiah, R. Rosli, and N. Abdullah, Effect of addition of inulin and fenugreek on the survival of microencapsulated Enterococcus durans 39C in alginate-psyllium polymeric blends in simulated digestive system and yogurt. Asian Journal of pharmaceutical sciences, 2015; 10: 350-361.
9. Lowy, F.D., Staphylococcus aureus infections. New England journal of medicine, 1998; 339: 520-532.
10. Dizaj, S.M., F. Lotfipour, M. Barzegar-Jalali, M.-H. Zarrintan, and K. Adibkia, Physicochemical characterization and antimicrobial evaluation of gentamicin-loaded CaCO3 nanoparticles prepared via microemulsion method. Journal of Drug Delivery Science and Technology, 2016; 35: 16-23.
11. Maleki Dizaj, S., F. Lotfipour, M. Barzegar-Jalali, M.-H. Zarrintan, and K. Adibkia, Ciprofloxacin HCl-loaded calcium carbonate nanoparticles: preparation, solid state characterization, and evaluation of antimicrobial effect against Staphylococcus aureus. Artificial cells, nanomedicine, and biotechnology, 2017; 45: 535-543.
12. Maleki Dizaj, S., F. Lotfipour, M. Barzegar-Jalali, M.-H. Zarrintan, and K. Adibkia, Application of Box–Behnken design to prepare gentamicin-loaded calcium carbonate nanoparticles. Artificial cells, nanomedicine, and biotechnology, 2016; 44: 1475-1481.
13. Edwards-Jones, V., R. Buck, S.G. Shawcross, M.M. Dawson, and K. Dunn, The effect of essential oils on methicillin-resistant Staphylococcus aureus using a dressing model. Burns, 2004; 30: 772-777.
14. Shahi, S., S.Z. Vahed, N. Fathi, and S. Sharifi, Polymerase chain reaction (PCR)-based methods: Promising molecular tools in dentistry. International Journal of Biological Macromolecules, 2018.
15. Odonkor, S.T. and J.K. Ampofo, Escherichia coli as an indicator of bacteriological quality of water: an overview. Microbiology research, 2013; 4: 2.
16. Sharifi, S., M. Samiei, S.Z. Vahed, S. Sunar, and S.M. Dizaj, A brief view on principle, mechanism and advantages of NanoPCR. Journal of Advanced Chemical and Pharmaceutical Materials, 2018; 1: 67-72.
17. Ghotaslou, R., A. Yaghoubi, and S. Sharify, Urinary Tract Infections in Hospitalized Patients during 2006 to 2009 in. J Cardiovasc Thorac Res, 2010; 2: 39-42.
18. Burt, S.A. and R.D. Reinders, Antibacterial activity of selected plant essential oils against Escherichia coli O157: H7. Letters in applied microbiology, 2003; 36: 162-167.
19. Singh, G., S. Maurya, and C.A. Catalan, A comparison of chemical, antioxidant and antimicrobial studies of cinnamon leaf and bark volatile oils, oleoresins and their constituents. Food and Chemical Toxicology, 2007; 45: 1650-1661.
20. Smith-Palmer, A., J. Stewart, and L. Fyfe, Antimicrobial properties of plant essential oils and essences against five important food-borne pathogens. Letters in applied microbiology, 1998; 26: 118-122.
21. Dizaj, S.M., A. Mennati, S. Jafari, K. Khezri, and K. Adibkia, Antimicrobial activity of carbon-based nanoparticles. Advanced pharmaceutical bulletin, 2015; 5: 19.