Antibacterial efficacy of Lemon Grass Oil (Cymbopogon citratus) on the type of bacteria and its count in Dental Aerosols

 

David Ditto Sharmin¹, K. Revathi², Jaideep Mahendra³, D. Anandhi⁴, M. Arun⁵,

J. Jasmine Vigila⁶

¹Ph.D. Scholar, Meenakshi Academy of Higher Education and Research (MAHER), Chennai.

²Directorate of Research, Meenakshi Academy of Higher Education and Research (MAHER), Chennai.

³Directorate of Research and Professor, Periodontology, Meenakshi Ammal Dental College, Maduravoyal, Chennai

⁴Assistant Professor, Biochemistry, Meenakshi Ammal Dental College, Chennai.

⁵Lab Technician, Meenakshi Ammal Dental College, Chennai.

⁶Ph.D. Scholar, Meenakshi Academy of Higher Education and Research (MAHER), Chennai.

 

ABSTRACT:

Dental aerosol disinfection should be considered as one of the most serious issues as they have very harmful microbial flora which could lead to multiple serious infections that commonly infect the operator, assistant, or the patients. Essential oils of nature like Lemon Grass have been proven recently to possess a greater action against gram-positive and gram-negative bacteria, Candida species, Streptococcus mutans, which are considered as the most prevalent oral microbial flora. Hence this study is aimed to determine the antibacterial effect of the Lemon Grass oil on dental aerosol bacteria around the dental unit during the dental procedure. Dental chairs with patients during treatment were included for the study where 5 agar plates with and without Lemon Grass oil application were placed in each chair at a distance of 1 – 1.5 m from the patient's mouth for 48hours and were incubated. Types of bacteria and its count were evaluated. Results showed significant contamination of bacteria in all plates without Lemon Grass oil application, whereas significant contamination was observed in all positive control plates. Lemon Grass represents an antibacterial source that can be as effective as modern medicine against pathogenic microorganisms especially the gram-positive and gram-negative bacteria which are usually present in dental aerosols.

 

 

INTRODUCTION:

Infection control is one of the main concerns in maintaining good hygiene within the dental office. Aerosol disinfection should be considered as a significant issue as they present with numerous infectious microbial flora and hence attempt should be made to eradicate them as they might result in serious complications.

 

Dental Aerosols contain a mixture of microorganisms as they incorporate the utilization of modern high-speed rotating instruments and subgingival scaling instruments within the mouth of the patients in the department of Endodontics and Periodontics respectively.¹ The extend of those aerosol spreads and their level of bacterial contamination has become a critical factor in the growing concern because the number of patients with antibiotic-resistant Staphylococcus aureus colonization has been increased.² Occurrence of those aerosol contaminations is unavoidable as many dental procedures incorporate the utilization of kit like headpieces, three-way syringes, polishing burs and rubber cups, use of compressed air, ultrasonic scalers, and dry operating sites.³ When inhaled, their smaller size allows penetration to the alveoli of the lower respiratory tract, where infectivity is greatly increased.⁴ Dental aerosol is taken into account to be risky because it not only affects the dentist but also whom all enter the office like clinicians, staff, patients, people accompanying patients, service people, etc.⁵ Therefore it has become a primary concern to prevent the spread of infection through aerosol and also to protect all instruments and immunocompromised patients at dental surgeries in hospital environments.

 

Though many medications in the era have been proven for their effectiveness against aerosol contamination, they possess marked adverse effects. Henceforth in recent times, there has been a marked shift towards herbal cures attributable to the pronounced cumulative and irreversible reactions of contemporary drugs.^6,7 Reddy et al., 2001, Atleb et al., 2003 have already reported the beneficiaries and antimicrobial activities of many plants.^8,9 The Clinical efficacy of many previously present antibiotics is being threatened by the emergence of multidrug-resistant pathogens¹⁰. Many infectious diseases have been known to be treated with natural remedies throughout the history of mankind. Natural products, either as pure compounds or as standardized plant extract, provide unlimited opportunities for brand spanking new drug leads owing to the unrivalled availability of chemical diversity. There is an eternal and urgent need to discover new antimicrobial compounds with diverse chemical structures and novel mechanisms of action for brand spanking new and re-emerging infectious diseases¹¹ Therefore researchers are increasingly turning their attention to folk medicine, trying to find new ends up in the development of better drugs against microbial infection.¹² However, the studies of antimicrobial activities of lemongrass are very limited towards the pathogenic bacteria in dental aerosols. Lemon Grass oil has been found to possess bactericidal, anti-bacterial, and anti-fungal properties, which are reminiscent of Penicillin in its effectiveness (Lutterodt et al., 1999).¹³ Mirghani et al., 2012 considered plant-based medicine as a secure alternative because they incline to possess similar or more efficacy than synthetic drugs without adverse reactions.¹⁴ Hence this study is aimed to determine the antibacterial effect of the lemongrass oil on dental aerosol bacteria around the dental unit during the dental procedure.

 

MATERIALS AND METHODS:

Data were collected for one year in two dental school clinics (clinic I - Department of Endodontics and clinic II – Department of Periodontics). Both the dental clinics were sufficed with a good air-conditioned indoor environment with separate cabins which were separated uniformly with dividers which contained 15 chairs each. Both the clinics received more than 80 patients with fallout samples (N 80).

Clinic-I and Clinic-II consisted of 30 chairs and all the chairs were included for the study placing 5 agar plates in each chair (150 plates) at a distance of 1 – 1.5 m from the patient’s mouth (Figure 1.). Apart from these two separate plates were placed as negative controls in the Central Research Laboratory department (CRL) where they did not receive any fallout samples. Sheep blood agar plates were used for sample collection during the procedures. The placement of plates in each chair is mentioned as follows,

1.     Lemon Grass oil 100%

2.     Lemon Grass 50%

3.     Lemon Grass 25%

4.     control

5.     control

 

Lemon Grass oils were applied to the plates employing the spread plate technique. (Figure 2.) In Clinic-I and II, the plates were opened for 30 minutes. After sample collection, the plates were transported to the CRL where they were incubated at room temperature 37°C for 48 hours. The colonies were analyzed macro and microscopically, being carried out micro-cultures to observe the bacterial structures, and later the species were identified using Berger’s manual. Biochemical tests were done to determine the pathogenicity of different bacteria.

 

Essential Oil Preparation:

The Lemon Grass Oil (Cymbopogon citratus) was purchased from Thai-China Flavours and Fragrances Co., Ltd., (510/3-4 SoiNgamwongwan 25, Muang, Nonthaburi 11000) shipped through amazon.

For all the concentrations, a standardized mix of a quantity of 150µl was used to perform the spread plate technique and their various concentrations were diluted using Dimethyl Sulfoxide (DMSO) as given below.

 

Essential oils and DMSO ratio (150 µl):

100% - 150 µl: 0 (Full strength)

50% - 75µl: 75µl (Lemon Grass: DMSO)

25% - 50µl: 100µl (Lemon Grass: DMSO)

 

 

Figure 1.

 

Spread plate technique

 

Figure 2.

 

Figure 3.

 

RESULTS:

Table 1. Clinic-I

 

Table 2. Clinic-II

 

The results showed significant contamination with all positive control samples without essential oil application in both the observation clinics during the procedures. Figure 3, Table 1 and 2 show the results of the bacterial fallout collection during dental procedures. The mean density of aerobic oral bacteria was 930 CFU/m²/h from each plate in Clinic - I and 1230 CFU/m²/h from every plate in Clinic - II.

 

Finally, in Clinic-I we observed the total contamination of Gram-negative rods which consisted of Escherichia coli species (51.25%) and Klebsiella species (23.19%). Apart from that we also found Gram-positive cocci, namely staphylococcus species (16.33%), and Gram-positive rods, namely Bacillus species (9.23%). Whereas in clinic-II the Gram-negative rods were found in abundant and most prominent ones were Escherichia coli species (57.33%) followed by Gram-positive cocci, namely staphylococcus species (22.66%) and the least two were Gram-negative rods, namely Klebsiella species (15.33%) and Gram-positive rods, namely Bacillus species (04.68%).

 

In both the clinics, Escherichia coli was found at a higher percentage as compared to other bacteria. Negative Control plates which were placed in the CRL department showed a negative result for all organisms. Contamination was practically non-existent (0%) in plates with essential oil application and also in negative controls.

 

DISCUSSION:

Aerosols are airborne substances that contain micro-organisms. Bio aerosols are those that occur as a consequence of certain dental treatments which pays the way for the spread of infection. These sorts of infection through splatter from the patient's mouth is taken into account as a significant risk not only to the dentist but also to many other health care providers.  Dental equipments like dental headpieces, airway syringes, ultrasonic scalers, and polishing units are known to produce aerosols during the procedures.¹⁵ Hence during this study, dental aerosols produced during the dental procedures carried out in Clinic I and Clinic II were considered. it is stated that the size of the particle may vary from 0.001μm to quite 100 μm. the tiniest particle size (ranging between 0.5 μm and 10 μm) has the foremost effective potential to penetrate the respiratory passages and thus the lungs, possessing the power to transmit the disease. periodontal disease, being multi-factorial, the mouth harbours innumerable bacteria and viruses from the tract, saliva, and dental plaque. These microorganisms get aerosolized when coming in touch with the dental equipment. Aerosols might not only contain bacteria but also HIV and tubercle bacillus.¹⁶ Therefore, within the present study, the bacterial contamination present within the dental aerosols was collected and identified for their varieties and pathogenicity. Aerosols may accommodate microorganisms like multi-resistant Staphylococcus aureus, influenza, legionnaire's disease, pneumonia, mumps, chickenpox, cytomegalovirus infection, hepatitis B and C virus infection, herpes simplex virus types 1 and a couple of infections, human immunodeficiency virus, etc.¹⁷

 

Usually, diseases just like the cold, sinusitis, and pharyngitis of the upper respiratory tract and Pneumonia, Tuberculosis, SARS, and Avian influenza of the lower respiratory tract has been reported with the aerosol contamination, Ragunath et al.¹⁸ For microbial air contamination, the average units of 45100-75000CFU/ m2/h in medical wards were given by Fischer et al.¹⁹ However, the results of the current study showed lesser counts than the suggested values, it also revealed that the positive control plates without Lemon Grass oil application showed the presence of various sorts of bacteria like Gram-positive cocci, namely Staphylococcus, Gram-negative bacilli, namely Klebsiella, and Escherichia species. Which was similar with the study done by Rautemaa et al 2006, where the microbial contamination in dental aerosol was proven within a distance of 1- 1.5m.²⁰

 

It was evident in an exceedingly study meted out by Micink 1969 that the extent of contamination was found to increase 1-1.5m from the patient's mouth and beyond that distance, the cross-infection was found to be minimal.²¹ Therefore in this study, considering the very best level of bacterial contamination all the agar plates were placed at a distance of 1 to 1.5m from the patient's mouth in both departments.

 

The adverse reactions of chemotherapeutics and the intensive antibiotic resistance exhibited by recent pathogens have led to the screening of medicinal plants for their innate antimicrobial potential.²² The Flower extract of Murraya paniculata shows antibacterial and antifungal activity.²³ Just like the two previous studies Lemon Grass which is also a plant-based extract is considered a preferred and important medicinal plant because it has various properties like: antibacterial, antifungal, antioxidant, antiseptic, astringent, anti-inflammatory, analgesic, antipyretic, and carminative property.^24,25 Essential Lemongrass oil is extracted from lemongrass which belongs to the family Gramineae and it falls during a section of Andropogon called Cymbopogamand its antibacterial and antifungal properties are akin to that of penicillin in its effectiveness.²⁶ Hence within the present study, it was more appropriate to use lemongrass oil than any other essential oils as it would possess a more robust antimicrobial activity against dental aerosol and also provide a much better aroma. The lemongrass essential oil even can retard the expansion of several sorts of microorganisms mainly at a degree ≤ of twenty-two.²⁷ Concerning this study, in the current study, the efficacy of lemongrass oil in various concentrations 100%, 50%, and 25% has been checked. The antibacterial activity was cent percent even in its minimal concentration (25%) and there was no significant difference within the antibacterial activity in any of the dilutions.

 

The healing properties of plants are due to the presence of characteristic secondary metabolites namely phenols, flavonoids, alkaloids, etc., which possess a major role in providing bioactivities like antimicrobial, antioxidant, antihelmintic, anticancer activities, etc. The plant-derived compounds become the bottom for the event of drug and should be used for the treatment of diseases. they are safer, have profound therapeutic benefits, and have cheaper treatments. There are not any or minimum side effects as compared to synthetic drugs and typically have effectiveness beyond the symptomatic treatment of diseases.^28,29 Shreds of pieces of evidence as mentioned prove that the constituents of lemongrass incorporate phenol and flavanoid substances that possess many biological actions like antioxidant, anti-inflammatory, and antimutagenic properties. Additionally, to those properties, lemongrass also possesses antimicrobial effects like anti-amoebic, antifungal, antimycobacterial, and antibacterial against both gram-positive and gram-negative organisms.^30,31 Hence within this study, it was easy to conclude that the strong antibacterial effect of Lemon Grass oil even in its minimal concentration was due to the presence of components like phenol and flavonoid substances.

 

Ultimately our study demonstrates that Lemon Grass oil represents an antibacterial source that can be as effective as modern medicine against pathogenic microorganisms especially the gram-positive and gram-negative bacteria which are usually present in dental aerosols and a secure alternative to be used in the prevention and treatment of aerosol spread infectious diseases. within the future, this Lemon Grass compound is often used collectively of the promising antibacterial agents within the type of liquid in aerosol contamination of the bacteria within the patient and also with the doctor or any others who are subjected to the aerosols.

 

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Accepted on 24.11.2021           © RJPT All right reserved

Research J. Pharm. and Tech 2022; 15(9):4024-4028.