Dental Research Journal

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 16  |  Issue : 3  |  Page : 153--159

The antibacterial activity of “Satureja hortensis” extract and essential oil against oral bacteria


Leila Golpasand Hagh1, Atefe Arefian1, Ahmad Farajzade2, Sana Dibazar3, Neda Samiea1,  
1 Department of Periodontology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
2 Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
3 Department of Operative and Esthetic Dentistry Dental Faculty, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

Correspondence Address:
Dr. Sana Dibazar
Dental Faculty, Ahvaz Jundishapur University of Medical Sciences, Ahvaz
Iran

Abstract

Background: Recently, there has been an increasing growth in research on medical plant's effect on dental plaque bacteria. The aim of this study was to determine the antibacterial effects of Satureja hortensis extract and its essential oil (EO) on Streptococcus salivarius, Streptococcus sanguis, and Streptococcus mutans as important bacteria in early supragingival dental plaque formation. Materials and Methods: In this in vitro study, different concentrations of S. hortensis extract and its EO were prepared using double dilution method. The disc diffusion method was used to determine antibacterial activity. Based on these measurements, the minimal inhibitory concentration value was reported for each bacterium. Antibiotics used as positive controls in this study were erythromycin (15 μg) and tetracycline (30 μg). t-test and ANOVA were used for statistical analysis (P < 0.05). Results: Aqueous and methanolic extract did not show significant antibacterial activity, but the EO significantly inhibited the growth of the test bacteria compared to positive control (P < 0.05). High concentrations of EO processed greater antimicrobial effects against three oral bacteria than other low concentrations (P < 0.0001). For S. mutans, the inhibition effect of tetracycline 30 μg was similar with 50% (P = 0.789) and 25% (P = 0.158) dosages of the EO. For S. salivarius, the effect of tetracycline 30 μg was similar to 50% dosages of the EO (P = 0.122). For S. sanguis, the effect of erythromycin 15 μg was lower than 50% (P = 0.0006) and 25% (P = 0.003) dosages of the EO. The inhibition effects of all concentrations of EO were higher for S. sanguis. S. salivarius and S. sanguis are more sensitive than S. mutans to S. hortensis EO. Conclusion: Due to the strong antibacterial effect of S. hortensis EO on the oral bacteria growth, it can be served as herbal mouth rinse, while to confirm this antibacterial effect, further clinical studies are necessary.



How to cite this article:
Hagh LG, Arefian A, Farajzade A, Dibazar S, Samiea N. The antibacterial activity of “Satureja hortensis” extract and essential oil against oral bacteria.Dent Res J 2019;16:153-159


How to cite this URL:
Hagh LG, Arefian A, Farajzade A, Dibazar S, Samiea N. The antibacterial activity of “Satureja hortensis” extract and essential oil against oral bacteria. Dent Res J [serial online] 2019 [cited 2019 Jul 19 ];16:153-159
Available from: http://www.drjjournal.net/text.asp?2019/16/3/153/255741


Full Text



 Introduction



Dental caries and periodontal diseases are two of the most important infectious diseases in the community at present.[1],[2] Accumulation of microbial plaque on tooth surfaces is one of the first stages of caries process and periodontal diseases.[3] The microbial plaque consists of a wide spectrum of bacteria with complex interactions. The dominant microbial composition of the dental plaque, which is often affected by the oral environment, can determine the potential for damage.[4] The basic stage in plaque formation is the ability of adherence for microorganism to dental and tissue surfaces. In early dental plaque formation, primarily Gram-positive cocci can attach to dental surfaces.[5] Recently, molecular methods such as proteomics and 16S rRNA sequencing demonstrate the predominant species of Streptococcus mutans, Streptococcus salivarius, Streptococcus sanguis, and Streptococcus mitis in the supragingival plaque.[6] Over time, Gram-negative bacteria are added to the plaque and complicate the plaque environment and so increase the potential for damage.[7]

Plaque control and good oral hygiene might be helpful in prevention and achievement of good treatment outcomes in this respect.[8] Different mechanical and chemical plaque control techniques have been introduced. However, many individuals do not properly use mechanical plaque control techniques.[9],[10] It has been demonstrated that even if adequate time is spent, only half of the plaque can be removed.[11]

In 2002, emphasis was put on the use of mouth rinses by the International Association for Dental Research as an adjunct to control plaque.[12] In this context, various mouth rinses were introduced to help control plaque. Of all these, chlorhexidine (CHX) is used as the most important antiplaque mouth rinse.[13] A systematic study has shown that CHX at concentrations of 0.06% to 0.2% is effective in decreasing bacterial plaque. In this respect, its overall dose is important for its efficacy.[14] Studies have shown that the optimal dose of CHX is 20 mg twice daily.[15] There is a direct relationship between the concentration of CHX and the incidence of complications at doses >0.1%.[16],[17],[18] Due to their side effects, including a change in taste and formation of stains on the teeth, and also the presence of chemical agents such as alcohol, preservatives, and synthetic pigments, many patients are not interested in the long-term use of chemical mouth rinses.[19],[20],[21] Therefore, in recent years, the idea of the use of herbal agents with antibacterial effects in the formulation of mouth rinses has drawn some attention to minimize complications.

Satureja L. (savory, saturei) is a plant with 30 different species belonging to the Lamiaceae family. This herbal medicine is indigenous to the Mediterranean area.[22] The aerial parts of the plant are white to pale pink-violet in color and its odor is a stimulant and has invigorating effects.[22],[23] Previous studies have reported a wide range of biologic properties for this plant, including antioxidative, anti-inflammatory, and analgesic effects.[24],[25]

A study by Adiguzel et al. revealed the antifungal and antibacterial effects of this plant against the fungi and bacteria in foodstuff.[26] In addition, a study by Sabzghabaee et al. showed the positive effect of its extract on the treatment of denture stomatitis due to Candida albicans.[27]

The aim of the present in vitro study was to evaluate the effect of Satureja hortensis L. extract on three important bacteria in early dental plaque formation, with S. mutans being the most important etiologic agent for dental caries pathogenicity and S. sanguis and S. salivarius as predominant microorganisms in pit and fissures of new erupted teeth and tongue covering plaque, respectively, through determination of minimal inhibitory concentration (MIC).[28],[29],[30],[31]

 Materials and Methods



In this in vitro study, to evaluate the antibacterial activity of S. hortensis extract and essential oil (EO) on test bacteria, different concentrations of aqueous and methanol extracts and EO were classified under six groups as follows:

Group 1 = 1.5625%Group 2 = 3.125%Group 3 = 6.25%Group 4 = 12.5%Group 5 = 25%Group 6 = 50%.

Plant material

The plant (S. hortensis L.) used in this work was collected from Hamidiyeh (Ahvaz, Khuzestan, Iran) in February 2015. After identifying the species by the herbarium section staff, the plant leaves were separated from shadow dried materials and then were powdered in a grinder.

Preparation of the aqueous and methanol extracts

The dried and powdered plant leaves (100 g) were extracted successively with 500 cc of methanol and 500 cc of water using Soxhlet extractor for 48 h at a temperature not exceeding the boiling point of the solvent. The aqueous and methanol extracts were filtered through Whatman filter paper and then concentrated in vacuo at 40°C by means of a rotary evaporator. The residues obtained were stored in a freezer until future tests.[32],[33],[34]

Isolation of the essential oil

One hundred gram of the fresh aerial parts of the plants collected was submitted to 500 cc of water distillation for 5 h using a Clevenger-type apparatus. Then, the EO was stored until future tests.

Microbial strains

The extracts and the EO were tested against three oral bacteria (S. mutans PTCC1683, S. salivarius PTCC1448, and S. sanguis PTCC1449). These bacteria were provided by the Iranian Type Culture Collection and then the lyophilized strains were inoculated on blood agar and then incubated for 18 h at 37°C. The precultures of bacteria were prepared for the susceptibility tests. For this purpose, the bacteria strains were taken by sterile inoculating loop touching to 4–5 colonies raised from pure microorganism culture, and these strains were inoculated in physiologic serum at the concentration of 1 × 108 CFU/ml (in order to achieve the McFarland no: 0.5 density) and then incubated at 37°C.

Disc diffusion assay

Extracts and EO were diluted in dimethyl sulfoxide (DMSO) to the different test concentrations (for extract test, concentrations were 5, 2.5, 1.25, 0.625, 0.3125, and 0.15625 mg/ml, and for EO test, concentrations were 50%, 25%, 12.5%, 6.25%, 3.125%, and 1.5625%). Antimicrobial tests were carried out by the disc diffusion method. The discs (6 mm diameter) were impregnated with 30 μl of the extracts and oil dilution and placed on the inoculated blood agar. Negative controls were prepared using the same solvents to dissolve the extracts and EO (DMSO). Tetracycline (30 μg) and erythromycin (15 μg) were used as positive reference standards to determine the sensitivity of a strain of each tested microbial species. The inoculated plates were incubated at 37°C for 18 h. Antimicrobial activity was evaluated by measuring the zone of inhibition against the test microorganisms. The least concentration of each extract and EO showing a clear zone of inhibition were taken as the MIC. The assays were performed three times for each bacterium.

Statistical analysis

Analysis of the results was performed by t-test and ANOVA using SPSS statistics software (version 16; SPSS Inc, Chicago, IL, USA) P > 0.05 was considered to be significant.

 Results



According to the results of this study, aqueous extract and methanol extract did not show significant antibacterial activity against the test bacteria compared to positive control as there was no inhibition zone even in high concentrations. However, the EO significantly inhibited the growth of the test bacteria.

Average and standard deviation of the inhibition zones of the bacteria by EO, negative control (DMSO), and positive control (tetracycline 30 μg and erythromycin 15 μg) are summarized in [Table 1].{Table 1}

The results demonstrated that there was a significant difference in inhibition zones of different concentrations. High concentrations of EO processed greater antimicrobial effects against three oral bacteria than other low concentrations (P < 0.0001).

For all bacteria, negative control DMSO did not show any inhibition zone.

The inhibition zone of different concentrations, except 1.5625% and 3.125% of concentrations for S. mutans and 1.5625% for S. salivarius and S. sanguis, was significant compared to negative control (P < 0.05).

For S. mutans, the inhibition effect of tetracycline 30 μg was similar to 50% (P = 0.789) and 25% (P = 0.158) dosages of the EO and was higher compared to lower concentrations.

For S. salivarius, the effect of tetracycline 30 μg was similar to 50% dosages of the EO (P = 0.206) and was higher compared to lower concentrations.

For S. sanguis, the effect of erythromycin 15 μg was lower than 50% (P = 0.0006) and 25% (P = 0.003) dosages of the EO and was similar to other concentrations.

The inhibition effects of 6.25% and 50% of concentrations of the EO were higher for S. sanguis and similar for S. salivarius and S. mutans.

The inhibition effects of 12.5% and 25% of concentrations of the EO for S. sanguis were higher amounts than S. mutans, and the differences were not significant for S. salivarius.

The MIC values of EO on target bacteria were as follows: S. mutans 3.125%, S. salivarius 1.5625%, and S. sanguis 1.5625%. Hence, S. salivarius and S. sanguis are more sensitive than S. mutans to S. hortensis EO [Table 2].{Table 2}

 Discussion



The results of the present study showed that the aqueous extract tested had no antibacterial effects on the three microorganisms evaluated; however, EO had strong antibacterial effect on S. mutans, S. salivarius, and S. sanguis. In the present in vitro study, to evaluate the effect of the extract and EO of S. hortensis on the three dominant microorganisms in the oral cavity, the MIC technique was used. In the majority of cases, MIC, minimum bactericidal concentration, minimum fungicidal concentration, MIC50, and lethal dose 50 (minimum lethal concentration) are used to evaluate the efficacy and effect of herbal components and for comparison of the required concentration to exhibit the growth of microorganisms.[35] The results of MIC test in the present study showed the antibacterial effects of 3.125% concentration on S. mutans and 1.56% concentration on S. sanguis and S. salivarius.

EOs are herbal components that have been prepared using hydrodistillation, steam distillation, or solvent extraction techniques and usually have a molecular weight <500 d.[36]

Herbal medicines have been used in different fields of traditional medicine. Currently, their efficacy has been shown with the use of new techniques for the analysis and identification of their chemical structure with scientific evidence.[37] EOs are usually the product of a combination of terpenoids and phenylpropanoids.[38] Several studies on different aspects of EOs have demonstrated their different properties, including antineoplastic (with necrosis and apoptosis of cancerous cells),[35],[39] antimutagenic (through inhibition of synthesis of P450),[40] antifungal and antioxidative (due to the presence of thymol and carvacrol),[41],[42] antiviral (through inhibition of viral proliferation), and anti-inflammatory (by inhibition of the release of free radicals) properties.[37] These products are lipophilic and therefore have the capacity to penetrate through the cell wall and cellular membranes. These compounds increase the permeability after they affect polysaccharides, phospholipids, and fatty acids of the cell membrane. In addition, they can affect the proton-pump mechanism and deactivate cellular enzymes after denaturing the plasma proteins to cause cellular death.[43],[44],[45]

The chemical structure and EO content of different species of Satureja L. are different. Evaluation of EO in S. hortensis L. has shown a high content of phenolic components, including carvacrol and γ-terpinene.[46] The concentrations of these compounds in descending order are as follows: carvacrol, cymene, α-pinene, terpineol, thymol, β-pinene, linalool, and borneol.[47] It should be pointed out, apart from the genus of the plant, the conditions affecting its growth, climate and geographical location, seasonal and temperature changes, and even conditions after its harvest affect the chemical composition of EOs.[48]

In a study by Zeidán-Chuliá et al. on the antibacterial properties of S. hortensis L. EO and M. Salvia fruticosa on Fusobacterium nucleatum, it was shown that both herbal EOs exhibited effective antibacterial properties against bacterial species above. However, the effect of S. hortensis L. was stronger due to a higher concentration of terpenes.[49]

In addition, Sharifi-Rad et al. evaluated the antineoplastic and antibacterial effects of EO of Satureja intermedia C.A. on S. salivarius and S. mutans and reported their effect on these bacterial species. The difference in MIC between the present study and the study above might be attributed to differences in concentrations of the ingredients of the herbal extracts; in this context, monoterpene hydrocarbons, γ-terpinene, thymol, and p-cymene exhibited the highest concentrations, respectively, and carvacrol comprised only a small percentage of the extract.[22]

Carvacrol is the chief ingredient of EO of this plant and an increase in the concentration of carvacrol and thymol results in an increase in its antibacterial activity; however, it should be pointed out that the antibacterial activity does not increase with only an increase in concentrations of these two compounds and the presence of other ingredients at proper concentrations will improve the performance of other ingredients with their synergistic effects.[50],[51] The most important mechanism of action of the EO of the plant under study is its ability to penetrate into the bacterial cell and its effect on the vital organelles of the microorganism after disrupting the permeability of the cell wall and cell membrane through its effect on the lipids of the cell membrane.[52] In addition, the ability of EOs to penetrate into microbial biofilms that are resistant to the penetration and effect of antibiotics[53] is an advantage apart from their antimicrobial properties, which might induce persistent and more effective effects in mouth rinses.

It should be emphasized that in vitro nature of the present study and other similar studies is some of the limitations here. In this context, the clinical use of EO in mouth rinses is associated with some complex issues. Based on the results of a study by Mohtashami et al., the concentrations of ingredients of EOs do not remain unchanged when they are stored under different conditions, with an increase in the concentration of carvacrol and a decrease in the concentration of ingredients with a low boiling point.[46]

Given the reciprocal effects of EO ingredients to induce proper antimicrobial effects, further studies are necessary to evaluate the antimicrobial effects of this extract under different storage conditions. In addition, the ingredients in the extract that are used for chemotherapy purposes in addition to their antimicrobial properties possibly exert toxic effects on the oral cavity mucosa, possibly inducing allergic reactions.[54] On the other hand, the oral cavity is a dynamic environment with different enzymes; therefore, it is possible that the ingredients of EO might undergo changes under the influence of oxidation and enzymatic reactions.[55],[56] Therefore, further and more comprehensive clinical studies are necessary before their clinical applications.

 Conclusion



Aqueous extract and methanol extract did not show significant antibacterial activity against the test bacteria, but the EO significantly inhibited the growth of the test bacteria. S. salivarius and S. sanguis are more sensitive than S. mutans to S. hortensis EO.

So due to the strong antibacterial effect of S. hortensis EO on the oral bacteria growth, it can be served as a herbal mouth rinse, but further clinical studies are necessary.

Financial support and sponsorship

This project was financially supported by Ahvaz Jundishapur University of Medical Sciences.

Conflicts of interest

The authors of this manuscript declare that they have no conflicts of interest, real or perceived, financial or nonfinancial in this article.

References

1Lamster IB. Antimicrobial mouthrinses and the management of periodontal diseases. Introduction to the supplement. J Am Dent Assoc 2006;137 Suppl 11:5S-9S.
2Marcenes W, Kassebaum NJ, Bernabé E, Flaxman A, Naghavi M, Lopez A, et al. Global burden of oral conditions in 1990-2010: A systematic analysis. J Dent Res 2013;92:592-7.
3Zaura E, Keijser BJ, Huse SM, Crielaard W. Defining the healthy “core microbiome” of oral microbial communities. BMC Microbiol 2009;9:259.
4Marsh PD, Zaura E. Dental biofilm: Ecological interactions in health and disease. J Clin Periodontol 2017;44 Suppl 18:S12-22.
5Palmer RJ Jr., Gordon SM, Cisar JO, Kolenbrander PE. Coaggregation-mediated interactions of streptococci and actinomyces detected in initial human dental plaque. J Bacteriol 2003;185:3400-9.
6Metwalli KH, Khan SA, Krom BP, Jabra-Rizk MA. Streptococcus mutans, Candida albicans, and the human mouth: A sticky situation. PLoS Pathog 2013;9:e1003616.
7Nyvad B, Fejerskov O. Transmission electron microscopy of early microbial colonization of human enamel and root surfaces in vivo. Scand J Dent Res 1987;95:297-307.
8Arora V, Tangade P, Ravishankar TL, Tirth A, Pal S, Tandon V. Efficacy of dental floss and chlorhexidine mouth rinse as an adjunct to toothbrushing in removing plaque and gingival inflammation – A three way cross over trial. J Clin Diagn Res 2014;8:ZC01-4.
9López-Jornet P, Plana-Ramon E, Leston JS, Pons-Fuster A. Short-term side effects of 0.2% alcohol-free chlorhexidine mouthrinse in geriatric patients: A randomized, double-blind, placebo-controlled study. Gerodontology 2012;29(4):292-8.
10Barnett F. Prevention of sports-related dental trauma: The role of mouthguards. Pract Proced Aesthet Dent 2003;15:391-4.
11Hancock EB, Newell DH. Preventive strategies and supportive treatment. Periodontol 2000 2001;25:59-76.
12DeVore L. The rinse cycle new research supports the benefits of adjunctive therapy with mouthrinses. RDH 2002;22:82-3.
13Jones CG. Chlorhexidine: Is it still the gold standard? Periodontol 2000 1997;15:55-62.
14Van Strydonck DA, Slot DE, Van der Velden U, Van der Weijden F. Effect of a chlorhexidine mouthrinse on plaque, gingival inflammation and staining in gingivitis patients: A systematic review. J Clin Periodontol 2012;39:1042-55.
15Cumming BR, Löe H. Optimal dosage and method of delivering chlorhexidine solutions for the inhibition of dental plaque. J Periodontal Res 1973;8:57-62.
16Flötra L, Gjermo P, Rölla G, Waerhaug J. Side effects of chlorhexidine mouth washes. Scand J Dent Res 1971;79:119-25.
17Van Strydonck DA, Timmerman MF, van der Velden U, van der Weijden GA. Plaque inhibition of two commercially available chlorhexidine mouthrinses. J Clin Periodontol 2005;32:305-9.
18Pizzo G, Guiglia R, Imburgia M, Pizzo I, D'Angelo M, Giuliana G, et al. The effects of antimicrobial sprays and mouthrinses on supragingival plaque regrowth: A comparative study. J Periodontol 2006;77:248-56.
19McCoy LC, Wehler CJ, Rich SE, Garcia RI, Miller DR, Jones JA, et al. Adverse events associated with chlorhexidine use: Results from the department of veterans affairs dental diabetes study. J Am Dent Assoc 2008;139:178-83.
20Haffajee AD, Yaskell T, Socransky SS. Antimicrobial effectiveness of an herbal mouthrinse compared with an essential oil and a chlorhexidine mouthrinse. J Am Dent Assoc 2008;139:606-11.
21Mor-Reinoso C, Pascual A, Nart J, Quirynen M. Inhibition of de novo plaque growth by a new 0.03 % chlorhexidine mouth rinse formulation applying a non-brushing model: A randomized, double blind clinical trial. Clin Oral Investig 2016;20:1459-67.
22Sharifi-Rad J, Sharifi-Rad M, Hoseini-Alfatemi SM, Iriti M, Sharifi-Rad M, Sharifi-Rad M, et al. Composition, cytotoxic and antimicrobial activities of Satureja intermedia C.A. Mey essential oil. Int J Mol Sci 2015;16:17812-25.
23Milos M, Radonic A, Bezic N, Dunkic V. Localities and seasonal variations in the chemical composition of essential oils of Satureja montana L. and S. cuneifolia Ten. Flavour Fragr J 2001;16:157-60.
24Eminagaoglu O, Tepe B, Yumrutas O, Akpulat HA, Daferera D, Polissiou M, et al. The in vitro antioxidative properties of the essential oils and methanol extracts of Satureja spicigera (K. Koch.) Boiss. and Satureja cuneifolia ten. Food Chem 2007;100:339-43.
25Ghazanfari G, Minaie B, Yasa N, Nakhai LA, Mohammadirad A, Nikfar S, et al. Biochemical and histopathological evidences for beneficial effects of Satureja khuzestanica Jamzad essential oil on the mouse model of inflammatory bowel diseases. Toxicol Mech Methods 2006;16:365-72.
26Adiguzel A, Ozer H, Kilic H, Cetin B. Screening of antimicrobial activity of essential oil and methanol extract of Satureja hortensis on foodborne bacteria and fungi. Czech J Food Sci 2007;25:81.
27Sabzghabaee AM, Davoodi N, Ebadian B, Aslani A, Ghannadi A. Clinical evaluation of the essential oil of “Satureja hortensis” for the treatment of denture stomatitis. Dent Res J (Isfahan) 2012;9:198-202.
28Prabu GR, Gnanamani A, Sadulla S. Guaijaverin – A plant flavonoid as potential antiplaque agent against Streptococcus mutans. J Appl Microbiol 2006;101:487-95.
29MacFarlane TW, Helnarska SJ. The microbiology of angular cheilitis. Br Dent J 1976;140:403-6.
30Topazian RG, Goldberg MH. Management of Infections of the Oral and Maxillofacial Regions. Philadelphia: WB. Saunders, 1981;232-66.
31Zomorodian K, Ghadiri P, Saharkhiz MJ, Moein MR, Mehriar P, Bahrani F, et al. Antimicrobial activity of seven essential oils from Iranian aromatic plants against common causes of oral infections. Jundishapur J Microbiol 2015;8:e17766.
32Waterman PG, Mole S. Analysis of Phenolic Plant Metabolites. Oxford; Blackwell Scientific; 1994:238pp.
33Parekh J, Jadeja D, Chanda S. Efficacy of aqueous and methanol extracts of some medicinal plants for potential antibacterial activity. Turk J Biol 2005;29:203-10.
34Shahi F, Hashemi A, Abdolmaleki K, Shahi Z, Amraei S. Antibacterial effects of Quercus brantii fruits and Stachys lavandulifolia methanol extracts on imipenemase-type metallo-beta lactamase-producing Pseudomonas aeruginosa. Res J of Pharmacognosy 2017;4:59-66.
35Bakkali F, Averbeck S, Averbeck D, Idaomar M. Biological effects of essential oils – A review. Food Chem Toxicol 2008;46:446-75.
36Nakatsu T, Lupo AT, Chinn JW, Kang RK. Biological activity of essential oils and their constituents. Stud Nat Prod Chem 2000;21:571-631.
37Raut JS, Karuppayil SM. A status review on the medicinal properties of essential oils. Ind Crops Prod 2014;62:250-64.
38Carson CF, Hammer KA, Riley TV. Melaleuca alternifolia (Tea tree) oil: A review of antimicrobial and other medicinal properties. Clin Microbiol Rev 2006;19:50-62.
39Dudai N, Weinstein Y, Krup M, Rabinski T, Ofir R. Citral is a new inducer of caspase-3 in tumor cell lines. Planta Med 2005;71:484-8.
40Gomes-Carneiro MR, Dias DM, De-Oliveira AC, Paumgartten FJ. Evaluation of mutagenic and antimutagenic activities of alpha-bisabolol in the Salmonella/microsome assay. Mutat Res 2005;585:105-12.
41Rao A, Zhang Y, Muend S, Rao R. Mechanism of antifungal activity of terpenoid phenols resembles calcium stress and inhibition of the TOR pathway. Antimicrob Agents Chemother 2010;54:5062-9.
42Miguel MG. Antioxidant and anti-inflammatory activities of essential oils: A short review. Molecules 2010;15:9252-87.
43Saad NY, Muller CD, Lobstein A. Major bioactivities and mechanism of action of essential oils and their components. Flavour Fragr J 2013;28:269-79.
44Oussalah M, Caillet S, Lacroix M. Mechanism of action of Spanish oregano, Chinese cinnamon, and savory essential oils against cell membranes and walls of Escherichia coli O157:H7 and Listeria monocytogenes. J Food Prot 2006;69:1046-55.
45Burt S. Essential oils: Their antibacterial properties and potential applications in foods – A review. Int J Food Microbiol 2004;94:223-53.
46Mohtashami S, Rowshan V, Tabrizi L, Babalar M, Ghani A. Summer savory (Satureja hortensis L.) essential oil constituent oscillation at different storage conditions. Ind Crops Prod 2018;111:226-31.
47Gursoy UK, Gursoy M, Gursoy OV, Cakmakci L, Könönen E, Uitto VJ, et al. Anti-biofilm properties of Satureja hortensis L. essential oil against periodontal pathogens. Anaerobe 2009;15:164-7.
48Hussain AI, Anwar F, Hussain Sherazi ST, Przybylski R. Chemical composition, antioxidant and antimicrobial activities of basil (Ocimum basilicum) essential oils depends on seasonal variations. Food Chem 2008;108:986-95.
49Zeidán-Chuliá F, Keskin M, Könönen E, Uitto VJ, Söderling E, Moreira JC, et al. Antibacterial and antigelatinolytic effects of Satureja hortensis L. essential oil on epithelial cells exposed to Fusobacterium nucleatum. J Med Food 2015;18:503-6.
50Sefidkon F, Sadeghzadeh L, Teymouri M, Asgari M, Ahmadi S. Antimicrobial effects of the essential oils of two Satureja species (S. khuzistanica Jamzad and S. bachtiarica Bunge) in two harvesting time. Iran J Med Aromatic Plants 2007;23:174-182.
51Ben Arfa A, Combes S, Preziosi-Belloy L, Gontard N, Chalier P. Antimicrobial activity of carvacrol related to its chemical structure. Lett Appl Microbiol 2006;43:149-54.
52Trombetta D, Castelli F, Sarpietro MG, Venuti V, Cristani M, Daniele C, et al. Mechanisms of antibacterial action of three monoterpenes. Antimicrob Agents Chemother 2005;49:2474-8.
53Galvão LC, Furletti VF, Bersan SM, da Cunha MG, Ruiz AL, de Carvalho JE, et al. Antimicrobial activity of essential oils against Streptococcus mutans and their antiproliferative effects. Evid Based Complement Alternat Med 2012;2012:751435.
54Vigan M. Essential oils: Renewal of interest and toxicity. Eur J Dermatol 2010;20:685-92.
55Turek C, Stintzing FC. Stability of essential oils: A review. Compr Rev Food Sci Food Saf 2013;12:40-53.
56Najafian S. Storage conditions affect the essential oil composition of cultivated Balm Mint Herb (Lamiaceae) in Iran. Ind Crops Prod 2014;52:575-81.