Antimicrobial effect of lemongrass oil against oral malodour micro-organisms and the pilot study of safety and efficacy of lemongrass mouthrinse on oral malodour

Exploring the Clinical Applications of Lemongrass Essential Oil: A Scoping Review

Lemongrass is a medicinal plant that produces essential oil with a variety of therapeutic properties. Although lemongrass essential oil (LGEO) is promising in clinical applications, the existing knowledge on the efficacy and safety of LGEO remains limited. This scoping review aimed to identify, summarize, and synthesize existing literature related to the clinical applications of LGEO to provide an overview of its potential therapeutic benefits for patients. Three databases (PubMed, Web of Science, Scopus) were used following the PRISMA-ScR guidelines to find articles published between 1 January 2013, and 1 November 2022. A total of 671 records were identified and 8 articles were included in this scoping review. The majority of patients received oromucosal and topical treatment. The results of the studies suggest that LGEO might be a useful tool in the treatment of periodontitis, gingivitis and oral malodour, with similar efficacy to chlorhexidine (anti-gingivitis effect) and doxycycline (periodontitis). Additionally, LGEO has the potential for treating pityriasis versicolor and preventing skin aging and may have anti-dandruff effects. These findings not only underscore the diverse clinical potential of LGEO but also emphasize its comparable efficacy to established treatments. Further research is imperative to comprehensively evaluate LGEO's effectiveness, safety, mechanisms of action, potential interactions with other medications, and its long-term tolerability across diverse populations.

Current and Potential Applications of Monoterpenes and Their Derivatives in Oral Health Care

Plant products have been employed in medicine for centuries. As the world becomes more health-conscious, there is a growing interest in natural and minimally processed products for oral health care. This has led to an increase in research into the bioactive compounds found in plant products, particularly monoterpenes. Monoterpenes are known to have beneficial biological properties, but the specific mechanisms by which they exert their effects are not yet fully understood. Despite this, some monoterpenes are already being used in oral health care. For example, thymol, which has antibacterial properties, is an ingredient in varnish used for caries prevention. In addition to this, monoterpenes have also demonstrated antifungal, antiviral, and anti-inflammatory properties, making them versatile for various applications. As research continues, there is potential for even more discoveries regarding the benefits of monoterpenes in oral health care. This narrative literature review gives an overview of the biological properties and current and potential applications of selected monoterpenes and their derivatives in oral health care. These compounds demonstrate promising potential for future medical development, and their applications in future research are expected to expand.

Comparative Evaluation of 0.25% Lemongrass Oil Mouthwash and 0.2% Chlorhexidine Mouthwash in Fixed Orthodontic Patients Suffering from Gingivitis

AIM

The aim of this study is to compare the antiplaque and antigingivitis efficacy of 0.25% lemongrass oil mouthwash and 0.2% chlorhexidine mouthwash in patients undergoing fixed orthodontic treatment, who are suffering from gingivitis.

MATERIALS AND METHODS

A total of 60 patients undergoing fixed orthodontic treatment with mild-to-moderate gingivitis were selected for the study. The patients were randomly divided into three groups of twenty each, that is, group I: 0.25% lemongrass oil mouthwash (n = 20); group II: 0.2% chlorhexidine mouthwash (n = 20); and group III: oral prophylaxis (n = 20). Baseline gingival index (GI) and plaque index (PI) were accessed followed by oral prophylaxis was done and the PI score was set to zero for all the patients. Patients were asked to swish their mouth with their respective mouthwashes and brushing (twice daily), that is, morning and before bedtime for 21 days. The PI and GI scores were recorded for all three groups on the 14th and the 21st days. The post hoc Bonferroni test was used for multiple comparisons of mean differences among variables after the application of the analysis of variance (ANOVA) test for comparison within the groups.

RESULTS

A lower PI and the GI were found in the lemongrass oil mouthwash group by the 14th and the 21st days, respectively, a statistically significant difference (p < 0.001) compared to the chlorhexidine mouthwash group.

CONCLUSION

The findings of the current study suggested that 0.25% lemongrass oil mouthwash has the potential to be used as a natural or herbal alternative to chlorhexidine mouthwash.

CLINICAL SIGNIFICANCE

It can be suggested that 0.25% lemongrass oil mouthwash may be a good herbal alternative to mouthwash containing 0.2% chlorhexidine gluconate.

Comparative Evaluation of Locally Administered 2% Gel Fabricated from Lemongrass Polymer and 10% Doxycycline Hyclate Gel as an Adjunct to Scaling and Root Planing in the Treatment of Chronic Periodontitis-A Randomized Controlled Trial

Background: Extracts of medicinal plant like lemongrass offer a new choice for optional antimicrobial therapy against various oral microorganisms. The objective of this study was to assess, verify, and compare the antimicrobial effectiveness of locally administered 2% lemongrass gel and 10% doxycycline hyclate gel as an adjunct to scaling and root planing (SRP) in treating chronic periodontitis. Method: This is a double-blind parallel arm randomized controlled study. Forty subjects were randomly divided into Group A and B for 2% lemongrass gel and 10% doxycycline hyclate gel, respectively. The clinical assessments of Gingival Index (GI), Plaque Index (PI), Probing Pocket Depth (PPD), and Clinical Attachment Level (CAL) together with microbial colony counts for Porphyromonas gingivalis, Actinomyces naeslundii, and Prevotella intermedia were done at baseline, 1st month, and 3rd month follow-ups. Results: The results showed there was a significant reduction in the mean scores of GI, PPD, and CAL clinical indices from baseline to the 1st and 3rd month follow-ups in both the 2% lemongrass gel and 10% doxycycline gel groups (p < 0.05). Similarly, there was significant reduction in mean CFU scores for all periodontal pathogens from baseline to 1st and 3rd month follow-ups in both the 2% lemongrass gel and 10% doxycycline gel groups (p < 0.05). Conclusions: It could be concluded that the local delivery of 2% lemongrass gel as an adjunct to scaling and root planing is effective and comparable to 10% doxycycline gel in the treatment of chronic periodontitis.

Effect of Lemongrass Essential Oil based Mouthwash against Microflora Associated with Dental Plaque

Mouthwash is one of the most convenient and effective method employed for dental plaque management. The aim of the undertaken study was to establish the antimicrobial and anti-biofilm properties of lemongrass essential oil (LGEO) based mouthwash on microbial flora from dental plaque and also check cytotoxicity of mouthwash formulation. Five main colonizers of dental plaque representing dental microflora and three different bacterial species mainly responsible for the formation of biofilm were selected in this study. LGEO based mouthwash was developed and its stability was also determined. The antimicrobial and anti-biofilm activity of LGEO based mouthwash has been evaluated against the representative dental microflora as per CLSI guidelines. Cytotoxicity of mouthwash was checked by globally used MTT assay employing NIH 3T3 mouse fibroblast cell line. The mouthwash has been found to exhibit the stability in its major component, citral and also found exhibit antimicrobial and anti-biofilm activity against dental microflora. No cytotoxic effect was observed on mouse fibroblast cell line. LGEO in formulated mouthwash being a natural, herbal material isolated from traditional medicinal plants appears as a good and effective substitute to control the microflora linked with dental plaque.

Evaluation of the Efficacy of Lacer HaliTM Treatment on the Management of Halitosis: A Randomized Double-Blind Clinical Trial

Background: Halitosis of oral origin is very common in the general population. Due to their antimicrobial properties, chlorhexidine-based products are widely used in the management of this condition, but these are associated with reversible side effects. In this study we evaluated the efficacy of Lacer Hali^TM mouthrinse and toothpaste in subjects with intraoral halitosis after several applications under normal conditions of use. Methods: In this randomized clinical trial with mouth rinse and toothpaste, single-center, double-blinded, parallel participants were assigned to an experimental group (Lacer Hali^TM,, n = 20), a positive control group (Halita^TM, n = 20), and a placebo group (n = 20). The active duration of the study was 18 days. The clinical follow-up evaluations were performed at five time points (T0, T1, T2, T3, and T4). The intensity of halitosis was evaluated by organoleptic measurement and the portable gas chromatograph OralChroma^TM. The data were analyzed using generalized mixed linear models. Results: Sixty patients completed the study. Lacer Hali^TM, in comparison with Halita^TM, did not show statistically significant differences at any time during the study except for the levels of hydrogen sulfide and total volatile sulfur compounds at 15 days, where Halita^TM was better. Compared to the placebo treatment, Lacer Hali^TM, was significantly more efficient, in terms of both the organoleptic evaluations at 8 days and the levels of hydrogen sulfide. Conclusions: Lacer Hali^TM is an alternative to chlorhexidine-based toothpaste and mouthwashes in the management of halitosis.

Effect of essential oils on oral halitosis treatment: a review

Halitosis is a very common condition which may affect up to 30% of the population. In about 90% of the cases, halitosis originates in the mouth due to inadequate plaque control, periodontal disease, dry mouth, faulty restorations, and in particular due to excessive bacterial growth. Oral malodor is mainly caused by a microbial degradation of amino acids into volatile, bad-smelling gases (volatile sulfur compounds - VSCs). Management of oral malodor is directed primarily at managing and reducing the VSC-producing bacteria count as well as masking the odor. Essential oils have been used for this purpose in traditional medicine for centuries. In the present review, data on the antimicrobial activity of essential oils against relevant oral VSC-producing bacteria are compiled and compared. Additionally, other positive aspects of essential oils with regard to oral odor are considered.

Interventions for managing halitosis

BACKGROUND

Halitosis or bad breath is a symptom in which a noticeably unpleasant breath odour is present due to an underlying oral or systemic disease. 50% to 60% of the world population has experienced this problem which can lead to social stigma and loss of self-confidence. Multiple interventions have been tried to control halitosis ranging from mouthwashes and toothpastes to lasers. This new Cochrane Review incorporates Cochrane Reviews previously published on tongue scraping and mouthrinses for halitosis.

OBJECTIVES

The objectives of this review were to assess the effects of various interventions used to control halitosis due to oral diseases only. We excluded studies including patients with halitosis secondary to systemic disease and halitosis-masking interventions.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 8 April 2019), the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 3) in the Cochrane Library (searched 8 April 2019), MEDLINE Ovid (1946 to 8 April 2019), and Embase Ovid (1980 to 8 April 2019). We also searched LILACS BIREME (1982 to 19 April 2019), the National Database of Indian Medical Journals (1985 to 19 April 2019), OpenGrey (1992 to 19 April 2019), and CINAHL EBSCO (1937 to 19 April 2019). The US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (8 April 2019), the World Health Organization International Clinical Trials Registry Platform (8 April 2019), the ISRCTN Registry (19 April 2019), the Clinical Trials Registry - India (19 April 2019), were searched for ongoing trials. We also searched the cross-references of included studies and systematic reviews published on the topic. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) which involved adults over the age of 16, and any intervention for managing halitosis compared to another or placebo, or no intervention. The active interventions or controls were administered over a minimum of one week and with no upper time limit. We excluded quasi-randomised trials, trials comparing the results for less than one week follow-up, and studies including advanced periodontitis.

DATA COLLECTION AND ANALYSIS

Two pairs of review authors independently selected trials, extracted data, and assessed risk of bias. We estimated mean differences (MDs) for continuous data, with 95% confidence intervals (CIs). We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 44 trials in the review with 1809 participants comparing an intervention with a placebo or a control. The age of participants ranged from 17 to 77 years. Most of the trials reported on short-term follow-up (ranging from one week to four weeks). Only one trial reported long-term follow-up (three months). Three studies were at low overall risk of bias, 16 at high overall risk of bias, and the remaining 25 at unclear overall risk of bias. We compared different types of interventions which were categorised as mechanical debridement, chewing gums, systemic deodorising agents, topical agents, toothpastes, mouthrinse/mouthwash, tablets, and combination methods. Mechanical debridement: for mechanical tongue cleaning versus no tongue cleaning, the evidence was very uncertain for the outcome dentist-reported organoleptic test (OLT) scores (MD -0.20, 95% CI -0.34 to -0.07; 2 trials, 46 participants; very low-certainty evidence). No data were reported for patient-reported OLT score or adverse events. Chewing gums: for 0.6% eucalyptus chewing gum versus placebo chewing gum, the evidence was very uncertain for the outcome dentist-reported OLT scores (MD -0.10, 95% CI -0.31 to 0.11; 1 trial, 65 participants; very low-certainty evidence). No data were reported for patient-reported OLT score or adverse events. Systemic deodorising agents: for 1000 mg champignon versus placebo, the evidence was very uncertain for the outcome patient-reported visual analogue scale (VAS) scores (MD -1.07, 95% CI -14.51 to 12.37; 1 trial, 40 participants; very low-certainty evidence). No data were reported for dentist-reported OLT score or adverse events. Topical agents: for hinokitiol gel versus placebo gel, the evidence was very uncertain for the outcome dentist-reported OLT scores (MD -0.27, 95% CI -1.26 to 0.72; 1 trial, 18 participants; very low-certainty evidence). No data were reported for patient-reported OLT score or adverse events. Toothpastes: for 0.3% triclosan toothpaste versus control toothpaste, the evidence was very uncertain for the outcome dentist-reported OLT scores (MD -3.48, 95% CI -3.77 to -3.19; 1 trial, 81 participants; very low-certainty evidence). No data were reported for patient-reported OLT score or adverse events. Mouthrinse/mouthwash: for mouthwash containing chlorhexidine and zinc acetate versus placebo mouthwash, the evidence was very uncertain for the outcome dentist-reported OLT scores (MD -0.20, 95% CI -0.58 to 0.18; 1 trial, 44 participants; very low-certainty evidence). No data were reported for patient-reported OLT score or adverse events. Tablets: no data were reported on key outcomes for this comparison. Combination methods: for brushing plus cetylpyridium mouthwash versus brushing, the evidence was uncertain for the outcome dentist-reported OLT scores (MD -0.48, 95% CI -0.72 to -0.24; 1 trial, 70 participants; low-certainty evidence). No data were reported for patient-reported OLT score or adverse events.

AUTHORS' CONCLUSIONS

We found low- to very low-certainty evidence to support the effectiveness of interventions for managing halitosis compared to placebo or control for the OLT and patient-reported outcomes tested. We were unable to draw any conclusions regarding the superiority of any intervention or concentration. Well-planned RCTs need to be conducted by standardising the interventions and concentrations.

Developing natural products as potential anti-biofilm agents

Biofilm is a natural form of bacterial growth ubiquitously in environmental niches. The biofilm formation results in increased resistance to negative environmental influences including resistance to antibiotics and antimicrobial agents. Quorum sensing (QS) is cell-to-cell communication mechanism, which plays an important role in biofilm development and balances the environment when the bacteria density becomes high. Due to the prominent points of biofilms implicated in infectious disease and the spread of multi-drug resistance, it is urgent to discover new antibacterial agents that can regulate biofilm formation and development. Accumulated evidences demonstrated that natural products from plants had antimicrobial and chemo-preventive properties in modulation of biofilm formation in the last two decades. This review will summarize recent studies on the discovery of natural anti-biofilm agents from plants with clear-cut mechanisms or identified molecular addresses, as well as some herbs with unknown mechanisms or unidentified bioactive ingredients. We also focus on the progression of techniques on the extraction and identification of natural anti-biofilm substances. Besides, anti-biofilm therapeutics undergoing clinical trials are discussed. These newly discovered natural anti-biofilm agents are promising candidates which could provide novel strategies for biofilm-associated infections.

Development of antibacterial denture cleaner for brushing containing tea tree and lemongrass essential oils

We evaluated effectiveness of tea tree oil (TO) and lemongrass oil (LO) for removal of Candida biofilm from denture base resin and their influence on that surface. Biofilm of C. albicans was formed on resins, and immersed in various concentrations of each oil and distilled water (DW). The biofilm removal effect was determined by incubating specimens in RPMI medium containing Alamar blue (AB) and measuring absorbance. Wear test was also conducted, and surface condition of resins was determined using laser scanning microscope and digital microscope. Specimens immersed in the TO and LO solutions tended to have a lower AB value at higher concentrations and longer soaking times. Use of these agents resulted in less surface roughness as compared to DW. Our results suggest that TO and LO were valid to remove biofilm attached to resin with lower levels of abrasion, and these are effective for use in denture cleaner.

Genuine halitosis in patients with dental and laryngological etiologies of mouth odor: severity and role of oral hygiene behaviors

The aims of the study were to determine the severity of halitosis and the association between oral hygiene practices and the severity of malodor in patients with dental and laryngological etiologies of genuine halitosis. Thirty-five laryngological and 40 dental patients with halitosis completed a structured interview and underwent laryngological and dental examinations. Halitosis was assessed using organoleptic and halimeter tests. Greater halitosis severity in laryngological patients was associated with worse clinical status of the palatine tonsils, less frequent toothbrushing, less frequent use of tongue cleaners, fewer daily meals, and increased use of mouthrinses. Among dental patients, more severe halitosis was associated with worse clinical status of the periodontium, more tongue coating, less saliva secretion, and less frequent use of dental floss, interdental toothbrushes, and tongue cleaners. Oral hygiene was found to be a key moderator of the relationship between status of the periodontium or tonsils and severity of halitosis. The severity of halitosis in laryngological patients and dental patients is essentially similar; however, oral hygiene routines are associated with different effects in each group. Consequently, individual recommendations for patients with halitosis should be adjusted for the underlying disease and emphasize the role of effective specific hygiene behaviors.

Effects of lemongrass oil and citral on hepatic drug-metabolizing enzymes, oxidative stress, and acetaminophen toxicity in rats

The essential oil from a lemongrass variety of Cymbopogon flexuosus [lemongrass oil (LO)] is used in various food and aroma industry products and exhibits biological activities, such as anticancer and antimicrobial activities. To investigate the effects of 200 LO (200 mg/kg) and 400 LO (400 mg/kg) and its major component, citral (240 mg/kg), on drug-metabolizing enzymes, oxidative stress, and acetaminophen toxicity in the liver, male Sprague-Dawley rats were fed a pelleted diet and administered LO or citral by gavage for 2 weeks. After 2 weeks of feeding, the effects of LO and citral on the metabolism and toxicity of acetaminophen were determined. The results showed that rats treated with 400 LO or citral had significantly reduced hepatic testosterone 6β-hydroxylation and ethoxyresorufin O-deethylation activities. In addition, NAD(P)H:quinone oxidoreductase 1 activity was significantly increased by citral, and Uridine 5′-diphospho (UDP) glucurosyltransferase activity was significantly increased by 400 LO in the rat liver. Treatment with 400 LO or citral reduced lipid peroxidation and reactive oxygen species levels in the liver. After acetaminophen treatment, however, LO and citral treatment resulted in little or no change in plasma alanine aminotransferase activity and acetaminophen-protein adducts content in the liver. Our results indicate that LO and citral may change the activities of drug-metabolizing enzymes and reduce oxidative stress in the liver. However, LO and citral may not affect the detoxification of acetaminophen.