Efficacy and safety of Melaleuca alternifolia (tea tree) oil for human health-A systematic review of randomized controlled trials.

Introduction: Leaves of the Australian tea tree plant Melaleuca alternifolia were used traditionally by First Nations Australians for treating wounds, burns, and insect bites. Tea tree oil, the essential oil steam-distilled from M. alternifolia, is well-known for its medicinal properties, the evidence for most applications however is limited. This review aimed to critically appraise evidence from clinical trials examining the therapeutic efficacy and safety of tea tree oil on outcomes. Methods: Randomized controlled trials with participants of any age, gender, or health status, comparing tea tree oil to any control were included, without limit on publication date. Electronic databases were searched on 12 August 2022 with additional records sourced from article reference sections, reviews, and industry white papers. Risk of bias was assessed by two authors independently using the Cochrane risk-of-bias 1.0 tool. Results were summarized and synthesized thematically. Results: Forty-six articles were eligible from the following medical fields (Dentistry n = 18, Dermatology n = 9, Infectious disease n = 9, Ophthalmology n = 6, Podiatry n = 3; and Other n = 1). Results indicate that oral mouthwashes with 0.2%-0.5% tea tree oil may limit accumulation of dental plaque. Gels containing 5% tea tree oil applied directly to the periodontium may aid treatment of periodontitis as an adjunctive therapy to scaling and root planing. More evidence is needed to confirm the benefits of tea tree oil for reducing acne lesions and severity. Local anti-inflammatory effects on skin, if any, also require further elucidation. Topical tea tree oil regimens show similar efficacy to standard treatments for decolonizing the body from methicillin-resistant Staphylococcus aureus, although intra-nasal use of tea tree oil may cause irritation to mucous membranes. Tea tree oil with added iodine may provide an effective treatment for molluscum contagiosum lesions in young children. More evidence on efficacy of tea tree oil-based eyelid wipes for Demodex mite control are needed. Side effects were reported in 60% of included studies and were minor, except where tea tree oil was applied topically in concentrations ≥ 25%. Discussion: Overall, the quality of research was poor to modest and higher quality trials with larger samples and better reporting are required to substantiate potential therapeutic applications of tea tree oil. Systematic Review Registration: PROSPERO, identifier [CRD42021285168].

The influence of Azadirachta indica, Melaleuca alternifolia, and Cocos nucifera on Candida albicans strain in tissue conditioner at varying time intervals.

AIM: The search for alternative therapies for oral candidiasis is a necessity and the use of medicinal plants seems to be one such promising solutions. Incorporation of phytotherapeutic agents, Azadirachta indica (neem oil), Melaleuca alternifolia oil (tea tree oil), and Cocos nucifera oil (coconut oil), were tested for their efficacy as antifungal agents against Candida albicans. Next, the efficacy of these three antifungal agents when incorporated in a soft relining material at minimum inhibitory concentration (MIC) was evaluated. SETTINGS AND DESIGN: Evaluative - In-vitro study design. MATERIALS AND METHODS: The MIC against C. albicans ATCC 24433 was calculated for M. alternifolia oil, A. indica oil, and C. nucifera oil using the broth microdilution method. Based on the preliminary screening results for MIC, tissue conditioner samples were prepared to evaluate the zone of inhibition (ZOI) and MIC. Antifungal activity of the MIC of the three oils was assessed and compared by measuring the mean ZOI. Antifungal activity of the three oils was assessed using one-way analysis of variance (ANOVA) and post hoc test. STATISTICAL ANALYSIS USED: Oneway ANOVA and post hoc Tukey honestly significant difference test. RESULTS: Inhibition against C. albicans was exhibited when 20% v/v, 25% v/v, and 15% v/v of C. nucifera oil, M. alternifolia oil, and A. indica oil were used, respectively. The results of ANOVA and post hoc test at the end of 48 h and 7 days suggested that all three oils were significantly different from each other (P = 0.000) and A. indica/neem oil with 15% concentration had the best antifungal activity at the end of 48 h and 7 days. CONCLUSION: The antimycotic activity of M. alternifolia, C. nucifera, and A. indica mixed with the Visco-gel tissue conditioner can be used as an alternative therapy for denture stomatitis.

New insights into the alleviating role of Melaleuca alternifolia oil on metabolites pathway disorder of grapes caused by Aspergillus niger, verified by corresponding key genes expression.

Grape berries are susceptible to Aspergillus niger (A. niger) infection during storage, leading to a significant reduction in its nutritional quality. However, most alternations in nutrient contents and related gene expression during fungal infection or treated with antimycotics remain unexplored. This work aimed to monitor and verify the metabolic changes in berries caused by A. niger or Melaleuca alternifolia oil (MAO) by using UHPLC-ESI-MS2 and Quantitative Real-time PCR (RT-qPCR). Results showed that sucrose, glucose, fructose, trans-resveratrol and pterostilbene levels were down and pentose phosphate pathway, glycolysis pathway and phenylpropanoid pathway were significantly down-regulated compared with healthy berries due to A. niger infection, all of which were alleviated by MAO treated. A. niger also induced down-regulation of key genes expression associated with metabolic pathways and magnitude of down-regulation was reduced by MAO. These results provide a theoretical basis for MAO used to control the risk of A. niger-mediated diseases.

The sensitivity of Demodex canis (Acari: Demodicidae) to the essential oil of Melaleuca alternifolia - an in vitro study / A sensibilidade do Demodex canis (Acari: Demodicidae) ao óleo essencial de Melaleuca alternifolia - um estudo in vitro

Abstract The essential oil of the Melaleuca alternifolia (Maiden & Betche) (tea tree oil) has been effective in previous studies, in the treatment of infestation by Demodex mites in humans. The present study aimed at evaluating the in vitro acaricidal effect of this herbal medicine on Demodex canis. For the parasitological examination, samples were collected from a dog's skin and examined using optical microscopy. Only samples with intact mites and with evident movement of chelicerae and tarsi were selected. Twenty-one samples were tested with the oil, in seven different concentrations: 100%; 50%; 25%; 12.5%; 6.25%; 5.0% and 3.13%. Three samples were tested with the positive control amitraz, and three with the negative control neutral shampoo. The interval between the time the solution was added and the moment the movement of the last mite ceased defined the survival time in the sample. By comparing the times at different concentrations and controls, the results showed that the higher the concentration of the oil, the more quickly its lethal effect occurred, and that the survival times in the controls were longer than in the different concentrations of melaleuca oil.

Resumo O óleo essencial de Melaleuca alternifolia (Maiden & Betche) (óleo da árvore do chá) foi eficaz em estudos anteriores, no tratamento da infestação por ácaros Demodex em humanos. O presente estudo teve por objetivo avaliar o tempo do efeito acaricida, in vitro, desse fitoterápico sobre Demodex canis. Para o exame parasitológico, amostras foram coletadas da pele de um cão e examinadas por microscopia óptica. Apenas amostras com ácaros íntegros e com evidente movimentação de quelíceras e tarsos foram selecionadas. Vinte e uma amostras foram direcionadas para teste com o óleo, em sete concentrações diferentes: 100%; 50%; 25%; 12,5%; 6,25%; 5,0% e 3,13%. Três amostras foram testadas com o controle positivo, amitraz, e três com o controle negativo, xampu neutro. O intervalo entre o momento em que a solução foi adicionada e o instante em que cessou o movimento do último ácaro definiu o tempo de sobrevivência na amostra. Os tempos nas diferentes concentrações e nos controles foram comparados. Quanto mais alta a concentração do óleo, mais rapidamente ocorreu seu efeito letal. Os tempos de sobrevivência nos controles foram maiores que nas diferentes concentrações do óleo de melaleuca.

Antifungal mechanisms of α-terpineol and terpene-4-alcohol as the critical components of Melaleuca alternifolia oil in the inhibition of rot disease caused by Aspergillus ochraceus in postharvest grapes.

AIMS: As a natural antimicrobial agent, Melaleuca alternifolia oil (MAO) is generally recognized to be safe and effective in the inhibition of phytopathogenic fungi. Due to lack of comprehensive studies on MAO for controlling postharvest Aspergillus, we investigated the preservative mechanism of MAO and its components against Aspergillus ochraceus in postharvest grapes to evaluate their potential effectiveness as fruit preservatives. METHODS AND RESULTS: In our study, the compositions in MAO were analysed by gas chromatography-mass spectrometry. The inhibitory effects of MAO and its main constituents against A. ochraceus were compared by scanning electron microscopy and transmission electron microscopy observation, and metabolic analysis. Two components of MAO, α-terpineol and terpene-4-alcohol, showed higher antifungal effects than MAO, of which α-terpineol caused the worst leakage of cytoplasm and most serious hyphae distortions and spore disruptions. The downregulation of metabolic pathways of A. ochraceus was strongest with α-terpineol. The best inhibitory efficacy against A. ochraceus in grapes also occurred with α-terpineol. 3-Carene showed little inhibitory effect. CONCLUSIONS: These results demonstrate that not all components in MAO possess antimicrobial effects, and α-terpineol is the main contributor of MAO's A. ochraceus inhibition effect. SIGNIFICANCE AND IMPACT OF THE STUDY: α-Terpineol may be used as an alternative natural preservative for the postharvest storage of grapes and other fruits.

Treatment of acne with a combination of propolis, tea tree oil, and Aloe vera compared to erythromycin cream: two double-blind investigations.

INTRODUCTION: Antibiotics that suppress Propionibacterium acnes are the standard treatment for acne but are becoming less effective, due to the appearance of antibiotic-resistant strains. Many plants are known to have innate antimicrobial action and can be used as alternatives to antibiotics; thus, it is necessary to prove their effectiveness in vivo. This study aimed to evaluate the anti-acne efficacy of a new cream based on three natural extracts, comparing it to erythromycin cream and placebo. PATIENTS AND METHODS: Sixty patients with mild to moderate acne vulgaris were randomly divided into three groups: treated with cream containing 20% propolis, 3% "tea tree oil", and 10% "Aloe vera" (PTAC) (n=20); or with 3 % erythromycin cream (ERC) (n=20); or with placebo (n=20). At baseline, after 15 and 30 days, investigators evaluated response to treatment by counting acne lesions through noninvasive measurements and macrophotography. RESULTS: All the clinical and instrumental values studied were statistically different from placebo except for sebometry, pHmetry, and erythema index values, measured on healthy skin. Unlike in the placebo group, papular and scar lesions showed high erythema reduction after 15 and 30 days of PTAC and ERC application. CONCLUSION: The PTAC formulation was better than ERC in reducing erythema scars, acne severity index, and total lesion count.

Analysis of pH and release of calcium of association between melaleuca alternifolia oil and calcium hydroxide / Análise de pH e liberação de cálcio da associação entre óleo de melaleuca alternifólia e hidróxido de cálcio

Introduction: The use of intracanal medications with antimicrobial properties is essential for decontaminating root canals during endodontic treatment. Calcium hydroxide is used for this because of its excellent properties. Melaleuca alternifolia oil has shown medicinal importance by demonstrating antifungal and bactericidal action against proven human pathogens. Objective: To evaluate the physical and chemical aspects such as pH and calcium release, of Melaleuca alternifolia oil associated with calcium hydroxide, during different time intervals. Material and method: Calcium hydroxide powder was added to vehicles to reach a concentration of 72mg / 0.1mL. Three groups were formed: Group I: Calcium Hydroxide + Distilled Water; Group II: Calcium hydroxide + Propylene Glycol; Group III: Calcium hydroxide + Melaleuca oil. The pH of each group was measured after time intervals of 10 minutes; 24 and 48 hours; 7, 15 and 30 days after tooling by a pH meter. Calcium release was analyzed by atomic absorption spectrometry equipped with a calcium hollow cathode lamp. Data were statistically analyzed by using the Kruskall-Wallis and Dunn test. Result: Group II showed high pH, similar to group III that remained uniform at 15 and 30 days. Calcium release that began after 24 hours, was similar in Groups II and III, and showed a peak release in 48 hours. Conclusion: The association of Melaleuca oil with calcium hydroxide showed good results in the pH and calcium release analyses, and showed action similar to that of propylene glycol + calcium hydroxide.

Introdução: O uso de medicações intracanais com propriedades antimicrobianas é fundamental para descontaminação dos canais radiculares durante o tratamento endodôntico. O hidróxido de cálcio é utilizado como medicação intracanal por apresentar excelentes propriedades. O óleo de Melaleuca alternifólia apresenta importância medicinal demonstrando ação antifúngica e bactericida comprovada contra patógenos humanos. Objetivo: Avaliar aspectos físico-químicos da associação do óleo de Melaleuca Alternifólia com hidróxido de cálcio, como: pH e liberação de cálcio durante diferentes períodos. Material e método: O pó do hidróxido de cálcio foi adicionado aos veículos até a concentração de 72mg/0,1mL. Foram divididos três grupos: Grupo I: Hidróxido de Cálcio + Água Destilada; Grupo II: Hidróxido de Cálcio + Propilenoglicol; Grupo III: Hidróxido de Cálcio + Óleo de Melaleuca. O pH de cada grupo foi medido após 10 minutos, 24, 48 horas, 7, 15 e 30 dias após a espatulação por um pHmetro. A liberação de cálcio foi analisada através da espectrometria de absorção atômica equipada com uma lâmpada cátodo para cálcio. Os dados foram analisados estatisticamente pelos testes de Kruskall-Wallis e Dunn. Resultado: O grupo II apresentou pH elevado, semelhante ao grupo III, permanecendo uniforme aos 15 e 30 dias. A liberação de cálcio iniciou em 24 horas, de forma semelhante nos grupos II e III e seu pico de liberação deu-se em 48 horas. Conclusão: A associação do Óleo de Melaleuca com hidróxido de cálcio apresentou bons resultados quanto à análise de pH e liberação de cálcio, demonstrando ação semelhante ao propilenoglicol + hidróxido de cálcio.