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Antifungal, cytotoxic, and immunomodulatory properties of tea tree oil and its derivative components: potential role in management of oral candidosis in cancer patients.

Ramage G, Milligan S, Lappin DF, Sherry L, Sweeney P, Williams C, Bagg J, Culshaw S - Front Microbiol (2012)

Bottom Line: The aims of the study were to evaluate the antifungal efficacy of TTO and key derivatives against C. albicans biofilms, to assess the toxicological effects of TTO on a clinically relevant oral cell line, and to investigate its impact on inflammation.Transcript and protein analysis showed a reduction of IL-8 when treated with TTO and T-4-ol.These data provide further in vitro evidence that TTO and its derivative components, specifically T-4-ol, exhibit strong antimicrobial properties against fungal biofilms.

View Article: PubMed Central - PubMed

Affiliation: Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow Glasgow, UK.

ABSTRACT
Candida albicans forms oral biofilms that cause disease and are difficult to treat with conventional antifungal agents. Tea tree oil (TTO) is a natural compound with reported antimicrobial and immunomodulatory activities. The aims of the study were to evaluate the antifungal efficacy of TTO and key derivatives against C. albicans biofilms, to assess the toxicological effects of TTO on a clinically relevant oral cell line, and to investigate its impact on inflammation. TTO and its derivatives were examined against 100 clinical strains of C. albicans. Planktonic minimum inhibitory concentrations (MICs) were determined using the CLSI M-27A broth microdilution method. Sessile MICs were determined using an XTT reduction assay. Inhibition, time-kill, and mode of action studies were performed. OKF6-TERT2 epithelial cells were used for cytotoxicity and cytokine expression assays. Planktonic C. albicans isolates were susceptible to TTO, terpinen-4-ol (T-4-ol), and α-terpineol, with an MIC(50) of 0.5, 0.25, and 0.25%, respectively. These three compounds also displayed potent activity against the 69 biofilm-forming strains, of which T-4-ol and α-terpineol displayed rapid kill kinetics. For all three compounds, 1 × MIC(50) effectively inhibited biofilm growth when C. albicans were treated at 0, 1, and 2 h post adhesion. By scanning electron microscopy analysis and PI uptake, TTO and derivative components were shown to be cell membrane active. TTO and T-4-ol were cytotoxic at 1 × MIC(50), whereas at 0.5 × MIC(50) T-4-ol displayed no significant toxicity. Transcript and protein analysis showed a reduction of IL-8 when treated with TTO and T-4-ol. These data provide further in vitro evidence that TTO and its derivative components, specifically T-4-ol, exhibit strong antimicrobial properties against fungal biofilms. T-4-ol has safety advantages over the complete essential oil and may be suitable for prophylaxis and treatment of established oropharyngeal candidosis. A clinical trial of T-4-ol is worthy of consideration.

No MeSH data available.


Related in: MedlinePlus

Tea tree oil and T-4-ol are cell membrane active. (A) Adherent cells (3153A) were adhered for 2 h on Thermanox™ coverslips and were (i) untreated (control), or treated with (ii) TTO, or (iii) T-4-ol at 2 × MIC50 for 24 h. These were then processed and viewed on an SEM. (B)C. albicans (3153A) planktonic cells (5 × 107 cells/ml) were treated with TTO, T-4-ol, or α-terpineol at a concentration of 2 × MIC50 for 10, 20, 30, 40, 50, and 60 min. The cells were washed by centrifugation, resuspended in PI (20 μM in PBS), and incubated for 15 min at 37°C. These were then transferred to a black 96-well plate for quantification in a fluorescent plate reader (Ex485/Em620). Each assay was performed on at least two independent occasions in triplicate. Error bars represent the ±standard error of the mean.
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Figure 3: Tea tree oil and T-4-ol are cell membrane active. (A) Adherent cells (3153A) were adhered for 2 h on Thermanox™ coverslips and were (i) untreated (control), or treated with (ii) TTO, or (iii) T-4-ol at 2 × MIC50 for 24 h. These were then processed and viewed on an SEM. (B)C. albicans (3153A) planktonic cells (5 × 107 cells/ml) were treated with TTO, T-4-ol, or α-terpineol at a concentration of 2 × MIC50 for 10, 20, 30, 40, 50, and 60 min. The cells were washed by centrifugation, resuspended in PI (20 μM in PBS), and incubated for 15 min at 37°C. These were then transferred to a black 96-well plate for quantification in a fluorescent plate reader (Ex485/Em620). Each assay was performed on at least two independent occasions in triplicate. Error bars represent the ±standard error of the mean.

Mentions: Scanning electron microscopy analysis of TTO and T-4-ol treated cells was performed. It was noted that compared to the control (untreated) cells (Figure 3Ai), both compounds had ruptured the cells, allowing the cell contents to leak out, giving a punctured appearance (Figures 3Aii,iii). The cell damage was shown to be more extensive for T-4-ol treated cells. Given this appearance we hypothesized that cell membrane integrity had been compromised. We therefore undertook PI uptake experiments, as previously reported (Sherry et al., 2012). For TTO, PI uptake was shown to be relatively slow, with maximal fluorescence obtained at 30 min (Figure 3B). In comparison, for T-4-ol fluorescence was shown to increase in a time dependent manner up to 40 min, twice that of TTO, after which time this reached a plateau. These data show similar kinetics to the time-kill data presented.


Antifungal, cytotoxic, and immunomodulatory properties of tea tree oil and its derivative components: potential role in management of oral candidosis in cancer patients.

Ramage G, Milligan S, Lappin DF, Sherry L, Sweeney P, Williams C, Bagg J, Culshaw S - Front Microbiol (2012)

Tea tree oil and T-4-ol are cell membrane active. (A) Adherent cells (3153A) were adhered for 2 h on Thermanox™ coverslips and were (i) untreated (control), or treated with (ii) TTO, or (iii) T-4-ol at 2 × MIC50 for 24 h. These were then processed and viewed on an SEM. (B)C. albicans (3153A) planktonic cells (5 × 107 cells/ml) were treated with TTO, T-4-ol, or α-terpineol at a concentration of 2 × MIC50 for 10, 20, 30, 40, 50, and 60 min. The cells were washed by centrifugation, resuspended in PI (20 μM in PBS), and incubated for 15 min at 37°C. These were then transferred to a black 96-well plate for quantification in a fluorescent plate reader (Ex485/Em620). Each assay was performed on at least two independent occasions in triplicate. Error bars represent the ±standard error of the mean.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
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Figure 3: Tea tree oil and T-4-ol are cell membrane active. (A) Adherent cells (3153A) were adhered for 2 h on Thermanox™ coverslips and were (i) untreated (control), or treated with (ii) TTO, or (iii) T-4-ol at 2 × MIC50 for 24 h. These were then processed and viewed on an SEM. (B)C. albicans (3153A) planktonic cells (5 × 107 cells/ml) were treated with TTO, T-4-ol, or α-terpineol at a concentration of 2 × MIC50 for 10, 20, 30, 40, 50, and 60 min. The cells were washed by centrifugation, resuspended in PI (20 μM in PBS), and incubated for 15 min at 37°C. These were then transferred to a black 96-well plate for quantification in a fluorescent plate reader (Ex485/Em620). Each assay was performed on at least two independent occasions in triplicate. Error bars represent the ±standard error of the mean.
Mentions: Scanning electron microscopy analysis of TTO and T-4-ol treated cells was performed. It was noted that compared to the control (untreated) cells (Figure 3Ai), both compounds had ruptured the cells, allowing the cell contents to leak out, giving a punctured appearance (Figures 3Aii,iii). The cell damage was shown to be more extensive for T-4-ol treated cells. Given this appearance we hypothesized that cell membrane integrity had been compromised. We therefore undertook PI uptake experiments, as previously reported (Sherry et al., 2012). For TTO, PI uptake was shown to be relatively slow, with maximal fluorescence obtained at 30 min (Figure 3B). In comparison, for T-4-ol fluorescence was shown to increase in a time dependent manner up to 40 min, twice that of TTO, after which time this reached a plateau. These data show similar kinetics to the time-kill data presented.

Bottom Line: The aims of the study were to evaluate the antifungal efficacy of TTO and key derivatives against C. albicans biofilms, to assess the toxicological effects of TTO on a clinically relevant oral cell line, and to investigate its impact on inflammation.Transcript and protein analysis showed a reduction of IL-8 when treated with TTO and T-4-ol.These data provide further in vitro evidence that TTO and its derivative components, specifically T-4-ol, exhibit strong antimicrobial properties against fungal biofilms.

View Article: PubMed Central - PubMed

Affiliation: Infection and Immunity Research Group, Glasgow Dental School, School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow Glasgow, UK.

ABSTRACT
Candida albicans forms oral biofilms that cause disease and are difficult to treat with conventional antifungal agents. Tea tree oil (TTO) is a natural compound with reported antimicrobial and immunomodulatory activities. The aims of the study were to evaluate the antifungal efficacy of TTO and key derivatives against C. albicans biofilms, to assess the toxicological effects of TTO on a clinically relevant oral cell line, and to investigate its impact on inflammation. TTO and its derivatives were examined against 100 clinical strains of C. albicans. Planktonic minimum inhibitory concentrations (MICs) were determined using the CLSI M-27A broth microdilution method. Sessile MICs were determined using an XTT reduction assay. Inhibition, time-kill, and mode of action studies were performed. OKF6-TERT2 epithelial cells were used for cytotoxicity and cytokine expression assays. Planktonic C. albicans isolates were susceptible to TTO, terpinen-4-ol (T-4-ol), and α-terpineol, with an MIC(50) of 0.5, 0.25, and 0.25%, respectively. These three compounds also displayed potent activity against the 69 biofilm-forming strains, of which T-4-ol and α-terpineol displayed rapid kill kinetics. For all three compounds, 1 × MIC(50) effectively inhibited biofilm growth when C. albicans were treated at 0, 1, and 2 h post adhesion. By scanning electron microscopy analysis and PI uptake, TTO and derivative components were shown to be cell membrane active. TTO and T-4-ol were cytotoxic at 1 × MIC(50), whereas at 0.5 × MIC(50) T-4-ol displayed no significant toxicity. Transcript and protein analysis showed a reduction of IL-8 when treated with TTO and T-4-ol. These data provide further in vitro evidence that TTO and its derivative components, specifically T-4-ol, exhibit strong antimicrobial properties against fungal biofilms. T-4-ol has safety advantages over the complete essential oil and may be suitable for prophylaxis and treatment of established oropharyngeal candidosis. A clinical trial of T-4-ol is worthy of consideration.

No MeSH data available.


Related in: MedlinePlus