An Overview of Essential Oils with Antibacterial Properties
Nur Sakinah Mahazir1, Siti Amira Othman1*
1 Faculty Applied Science and Technology, University Tun Hussein Onn Malaysia Pagoh, Johor
*Corresponding Author: [email protected] Accepted: 15 November 2021 | Published: 1 December 2021
DOI:https://doi.org/10.55057/ajfas.2021.2.4.1
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Abstract: Essential oils are now commonly utilised in the home and business because of their aromatherapy properties, which can help users relax. Plants with aromas, such as cinnamon, lemongrass, and peppermint, have essential oils produced from them. Essential oils' antioxidant, antibacterial, antifungal, antiviral, and anti-infectious characteristics make them useful in the food and pharmaceutical industries.
Keywords: essential oil, antimicrobial, antibacteria
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1. Introduction
Essential oils are natural compounds made from aromatic plant elements like cinnamon, lemongrass, or peppermint. It has strong antibacterial properties against a variety of microorganisms. Essential oils have numerous applications in the food and pharmaceutical industries due to their antioxidant, antibacterial, antifungal, antiviral, and anti-inflammatory characteristics (Rezaei et al., 2021). Essential oils can also be used as aromatherapy by releasing them into the air (smelling) or by massaging them into our bodies, giving us a calming sensation.
In dialysis patients, inhaling essential oils can have a calming and soothing impact, as well as reduce tension, improve memory, and reduce anxiety (Ebrahimi et al., 2021)(Nasiri & Boroomand, 2021). According to another researcher, different essential oils have distinct effects on users, for example, aromatherapy massage with rosemary oil made participants more alert, active, and pleasant than other smells (Nasiri & Boroomand, 2021). Thymol and carvacrol are the two main constituents of essential oils. Essential oils are usually put through a series of tests before being approved for use.
2. Literature Review
Essential oils, according to the researchers, have potent antibacterial and antiviral characteristics that prevent the production of mature biofilms. The eugenol and thymol monoterpernoids in plant essential oils show anti-caries activity against polymicrobial biofilms (Streptoccus sanguinis, S, mutans.). According to study, eugenol is effective against biofilms of two oral pathogens and can also be used in combination with azithromycin and fluconazole to treat oral infections. Essential oils derived from oregano, carnation, thyme, and cinnamon plants have the strongest antibacterial properties against S. mutans (Badekova et al., 2021). Skin-related microorganisms, dental cavities, and bacteria can all be controlled with essential oils and their extracts from certain plant species.
Terpenoids, aldehydes, and phenolic compounds are compounds found in essential oils that have antibacterial properties (Yang et al., 2021).
The classic approach for extracting vital plant oil is hydro-distilling (HD). However, time and energy consumption for this procedure are typically necessary, as well as low yields and deterioration of thermosensitive components (Mohamed Hanaa et al., 2012) (Razola-Díaz et al., 2021). As a replacement, green, and effective technology for the separation of essential plant oils without utilising organic solvent, microwave-assisted hydrodistillation integrated with the dielectrical microwave heating is offered. Another method of extraction aided by Microwave (MAE) that easily and swiftly diffuses essential oil from the raw material of plants. The output and quality of essential oil hence also decreases time and energy consumption. The vibration of water and other Polar molecules resulting from the radiation of the microwave are essentially the reason of essential oil separation utilising MAE. By this procedure, the temperature and pressure within plant cells increase immediately (Z. Liu et al., 2021).
3. Methodology
Several essential oils for determined anti-microbial activity were employed in this work. Essential oils are usually hydrophobic fluids consisting of volatile plant chemicals. They are volatile and unstable, waterproof and bioavailable they are low (Rezaei et al., 2021). They are also exceedingly light-sensitive, oxidising and heating.
Oregano essential oil
Oregano (Origanum vulgare) is an aromatic herb and also its dried aromatic sheets. Usually these herbs are used for seasonal meals. Hydrodistillation, ethanol removal, gas chromatography/mass spectrometry, and high-performance liquid chromatography technology have been used to obtain the essential oregano oil. The antimicrobial activity of oregano essential oil against S. mutans biofilm was investigated, and an anti-caries gel containing oregano extract and essential oil was created. The antibacterial activity of the gel on microbiological strains was determined in vitro.
For antibacterial activity, strains of the gram-positive bacteria Staphylococcus aureus were utilised, whereas strains of the gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, and the yeast fungus Candida albicans were used.
The bacteria's comparator is benzylpenicillin, and the yeast fungus C. albicans' comparator is nystatin. A suspension containing a standard number of viable bacterial cells was created for this study. In petri dishes, lawn was inoculated on the medium surface, and 0.01 ml anti-caries was applied to sterile filter paper discs. Discs with preparations were placed 2.5 cm from the centre of the dish circle, and the inoculation was incubated at 36°C for 24 hours. A homogenous bacterial lawn around the disc after inoculations aided the establishment of zones of total and partial bacterial growth inhibition (Badekova et al., 2021).
The biofilm was produced on the polystyrene surface of the flat bottom wells of 24 well cell culture plates using the S.mutans strain. In pure dimethyl sulfoxide, a stock concentration of oregano essential oil of 100 mg/ml was prepared (DMSO). The plate wells were dispensed with S. mutans biofilm formation and treatment enhanced with 1% sucrose. Then, at final concentrations of 2mg/ml, 4mg/ml, 6mg/ml, 8mg/ml, and 10mg/ml, the oregano essential oil solution. The strains were inoculated into the plate wells at a final dilution of 1:100 and incubated at 37°C for 24 hours
under anaerobic conditions. The plate wells included blank controls, S.mutans cells that had not been treated, and S.mutans cells that had only been treated with DMSO.
After 24 hours of incubation, the biomass of S.mutans biofilm was measured using a colorimetric technique.
Cinnamon Essential Oil
Cinnamon is widely employed in a variety of applications, including pharmaceuticals, seasonings, cosmetics, foods, beverages, commodity essences, and chemical industries. Cinnamon is also commonly utilised in natural medicine. Terpenes, limonene, cinnamaldehyde, and aromatic compounds in cinnamon essential oil show a high antibacterial action against foodborne pathogens such as Escherichia coli and Literia monocytogens (Yang et al., 2021). (X. Liu et al., 2021).
Essential oils have a short shelf life and have a detrimental impact on food odour due to their volatilization characteristics and sensitivity to external factors such as oxygen, light, and heat, according to Carvalho (2016). They have a strong scent and a limited water solubility, which limits their use. Liquid essential oils can be converted into solid nanocapsule powder using nanoencapsulation technology, which improves their stability. The method of high pressure homogenization (HPH) is used to make nanoemulsions.
Furthermore, the method's advantage is that the formation of nanoscale emulsions is independent of the component's hydrophilic-lipophilic balance. Small particles with a homogeneous particle size distribution and good stability can be created in this manner.
Saccharomyces cerevisiae was grown at 4°C on nutritional agar medium to determine antibacterial activity. A little amount of Saccharomyces cerevisiae was transferred from Bengal red medium to sterile water and cultivated at 28°C for 48 hours before being diluted to 106 CFU/mL. A small amount of bacterial starins was transferred from the nutrient agar medium to sterile water and cultured for 24 hours at 37°C with agitation before being diluted to 106 CFU/mL. (X. Liu et al., 2021).
Verbesina Essential Oil
The genus Verbesina (Asteraceae family) contains species that have been utilised by communities to make drinks, teas, infusions, and extracts that have been used as popular treatments for diabetes, hypertension, and antibacterial therapy. Their leaves were used to extract verbesina essential oil.
Seven microbial starins that cause respiratory and urinary tract infections were tested against the essential oil. Gram-positive bacteria included Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumonia. Gram-negative bacteria included Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumonia.
Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were used to measure antibacterial activity (MBC). In Mueller-Hinton broth, two-fold serial dilutions of each solution containing the essential oil from 0.5 to 1024 g/mL were made. After that, 10 litres of bacterial suspension were added. A resazurin solution (0.01 percent w/v) was utilised as a growth indicator, with the lowest concentration causing no colour change. Following that, 10 litres of the cultures were seeded on Muller Hilton Agar plates and cultured for 24 hours at 37 degrees Celsius to determine the minimal bactericidal concentration (MBC).
4. Result and discussion
Essential oil Result and discussion References
Oregano essential oil In the 24 well cell culture plates, treatment with oregano essential oil at a concentration of 2 mg/ml resulted in a small reduction in biofilm production in the bottom of the wells. S.mutans biofilm accumulation at the bottom of the wells in the 24 well cell culture plates was almost totally prevented by oregano essential oil at concentrations of 4mg/ml, 6mg/ml, 8mg/ml, and 10mg/ml.
S.mutans biofilm biomass was reduced by 9% in the presence of 2 mg/ml oregano essential oil compared to the untreated control bacterium. However, as compared to the untreated control bacteria, different concentrations of oregano essential oil significantly reduced S.mutans biofilm biomass by 98 percent.
According to another researcher, thymol and carvacrol monoterpenes derived from oregano essential oil have excellent bactericidal and antibiotic filtration action against S.mutans, suggesting that they could be used as a green option to prevent dental caries.
(Badekova et al., 2021)
Cinnamon essential oil The stability, solubility, and antibacterial activity of essential oils encapsulated in nanoemulsions were improved. CEO nanoemulsions were shown to be more visible on Escherichia coli (Gram-negative bacteria) than on Staphylococcus aureus (Gram- positive bacteria). Gram-negative bacteria were shown to be more responsive to antibiotics than gram- positive bacteria.
This is because the major component of the essential oil, cinnamonaldehydes, has target sites on the outer and inner membranes of Gram negative bacteria.
Cinnamonaldehydes rapidly reaches cell plasma and kills it when the outer membrane is disrupted. This causes cytoplasmic leakage and a powerful bactericidal action. The antibacterial activity of CEO nanoemulsion is broad, however the sensitivity of the test microorganism to the nanoemulsion varies depending on the strain.
(X. Liu et al., 2021)
Verbesina essential oil The antibacterial activity of verbesina essential oil was found to be superior to the antibiotic used as a standard (amikacin) in K. pneumonia, with lower MIC values for gram-negative bacteria.
Caryophyllene and germacrene D, which are found in Juniperus rigida and Hymenaea rubriflora essential oils, show antibacterial activity against K. pneumonia by causing cell wall and membrane morphological damage.
(de Veras et al., 2021)
Conclusion
To summarise, essential oils have strong antibacterial action, however pure extract essential oils have poor stability and water insolubility.The flaw could have an impact on the flavour of foods used in food products.One way for increasing the stability, solubility, and antibacterial action of essential oils is to use nanoemulsion (X. Liu et al., 2021). Furthermore, essential oils combined with polyvinyl alcohol (PVA), gum Arabic (GA), and chitosan (CS) can suppress bacterial development, making them promising options to wound dressing and packaging materials (Amalraj et al., 2020).
Acknowledgement
Authors would like to thank Universiti Tun Hussein Onn Malaysia for make this research possible.
References
Amalraj, A., Haponiuk, J. T., Thomas, S., & Gopi, S. (2020). Preparation, characterization and antimicrobial activity of polyvinyl alcohol/gum arabic/chitosan composite films incorporated with black pepper essential oil and ginger essential oil. International Journal of Biological Macromolecules, 151, 366–375. https://doi.org/10.1016/j.ijbiomac.2020.02.176
Badekova, K. Z., Atazhanova, G. A., Kacergius, T., Akhmetova, S. B., & Smagulov, M. K. (2021).
Composition and screening of Origanum vulgare essential oil for antimicrobial activity.
Journal of Taibah University Medical Sciences, xxxx.
https://doi.org/10.1016/j.jtumed.2021.05.009
de Veras, B. O., de Oliveira, J. R. S., de Menezes Lima, V. L., do Amaral Ferraz Navarro, D. M., de Oliveira Farias de Aguiar, J. C. R., de Medeiros Moura, G. M., da Silva, J. W., de Assis, C. R. D., Gorlach-Lira, K., de Assis, P. A. C., de Souza Barbosa, J. I., de Melo, M. R. C. S., de Oliveira, M. B. M., da Silva, M. V., & de Souza Lopes, A. C. (2021). The essential oil of the leaves of Verbesina macrophylla (Cass.) S.F.Blake has antimicrobial, anti-inflammatory and antipyretic activities and is toxicologically safe. Journal of Ethnopharmacology, 265(July 2020). https://doi.org/10.1016/j.jep.2020.113248
Ebrahimi, H., Mardani, A., Basirinezhad, M. H., Hamidzadeh, A., & Eskandari, F. (2021). The effects of Lavender and Chamomile essential oil inhalation aromatherapy on depression, anxiety and stress in older community-dwelling people: A randomized controlled trial.
Explore, 000. https://doi.org/10.1016/j.explore.2020.12.012
Liu, X., Chen, L., Kang, Y., He, D., Yang, B., & Wu, K. (2021). Cinnamon essential oil nanoemulsions by high-pressure homogenization: Formulation, stability, and antimicrobial activity. Lwt, 147(May). https://doi.org/10.1016/j.lwt.2021.111660
Liu, Z., Li, H., Cui, G., Wei, M., Zou, Z., & Ni, H. (2021). Efficient extraction of essential oil from Cinnamomum burmannii leaves using enzymolysis pretreatment and followed by microwave-assisted method. Lwt, 147(February). https://doi.org/10.1016/j.lwt.2021.111497 Mohamed Hanaa, A. R., Sallam, Y. I., El-Leithy, A. S., & Aly, S. E. (2012). Lemongrass
(Cymbopogon citratus) essential oil as affected by drying methods. Annals of Agricultural Sciences, 57(2), 113–116. https://doi.org/10.1016/j.aoas.2012.08.004
Nasiri, A., & Boroomand, M. M. tamed. (2021). The effect of rosemary essential oil inhalation on sleepiness and alertness of shift-working nurses: A randomized, controlled field trial.
Complementary Therapies in Clinical Practice, 43(July 2020).
https://doi.org/10.1016/j.ctcp.2021.101326
Razola-Díaz, M. del C., Guerra-Hernández, E. J., García-Villanova, B., & Verardo, V. (2021).
Recent developments in extraction and encapsulation techniques of orange essential oil. Food Chemistry, 354(December 2020). https://doi.org/10.1016/j.foodchem.2021.129575
Rezaei, A., Khavari, S., & Sami, M. (2021). Incorporation of thyme essential oil into the β- cyclodextrin nanosponges: Preparation, characterization and antibacterial activity. Journal of Molecular Structure, 1241, 130610. https://doi.org/10.1016/j.molstruc.2021.130610
Yang, K., Liu, A., Hu, A., Li, J., Zen, Z., Liu, Y., Tang, S., & Li, C. (2021). Preparation and characterization of cinnamon essential oil nanocapsules and comparison of volatile components and antibacterial ability of cinnamon essential oil before and after encapsulation.
Food Control, 123(November 2020). https://doi.org/10.1016/j.foodcont.2020.107783
