Tea Tree Oil-Based Hand Sanitizer Provides Robust Antimicrobial Properties

Written by Taylor Woosley, Staff Writer. Disinfectant treatment containing 10% tea tree oil provided comparable levels of antimicrobial properties to alcohol-based hand sanitizers, while also outperforming the efficacy of benzalkonium chloride treatment. 

Universally, washing hands with soap and water is a crucial hygiene measure to manage transmission of pathogens ¹. In instances where water and soap are not available, the U.S. Centers for Disease Control and Prevention (CDC) recommends the use of hand sanitizers, particularly those containing at least 60% alcohol, as an acceptable method of hand hygiene ². The average alcohol-based hand sanitizers (ABHS) contain isopropyl alcohol and ethanol, with alcohol levels ranging from 60% to 95% ³. With the recent high demand for ABHS, non-traditional drug manufacturers ABHC have entered the market, with some containing high levels of chemical impurities or alcohol amounts which can lead to extensive harm with frequent exposure ⁴.

Tea tree oil (TTO), an essential oil extracted from Australian Melaleuca alternifolia by steam distillation, is a common ingredient found in plant-based hand sanitizers because it is valued globally for its antimicrobial properties ⁵. TTO contains over 100 different bioactive compounds and one of its major chemotypes, terpinen-4-ol, is a naturally occurring monoterpene alcohol ⁶. Its robust chemical properties allow for a broad spectrum of antimicrobial activity against a variety of bacteria, fungi, and viruses ⁷.

In this randomized, controlled trial, Youn et al. observed the affects of tea tree oil as a natural approach to hand sanitation. Participants (n=106, age 18-60) were divided into four groups:

During the experiment, subject’s hands were contaminated with the marker microorganism Serratia marcesens and a glove juice sampling procedure was applied using the MacConkey agar pate culture test medium. After applying the microorganisms to both hands, drying the hands, applying a latex glove to the right hand and injecting saline into the glove, the sample was collected from the saline solution and inoculated. The experiment was then repeated a second time with each subject and group but this time after contaminating the subject’s hands, they were instructed to use the selected disinfectant and to rub and wash their hands thoroughly for at least 30 seconds. Primary outcomes were the measure of adenosine triphosphate (ATP), which was assessed using the ATP Surface Test kit and a Clean-Trace Luminometer to evaluate the presence of surface organisms using bioluminescence. Secondary outcomes were the assessment of subjective skin conditions based on skin moist-ness, dryness, and exfoliation using a 5-point Likert scale. Additionally, the measurement of transepidermal water loss was assessed using the gpskin Barrier probe.  After completion of the trial, the results were as follows:

• Significant differences in the mean ATP log₁₀ were noted after treatment (F = 13.47, p < .001), with significant differences noted in the amount of change: log₁₀46 RLU, log₁₀ 0.41 RLU, log₁₀ 0.42 RLU and log₁₀ 0.11 RLU in the tea tree oil, alcohol, benzalkonium chloride and control groups, respectively (F = 3.23, p = .025).
• After the experimental treatment, significant differences in changes in microbial counts were observed (F = 92.14, p < .001).
• Significant differences were noted in the amount of change: log₁₀50 ± 1.90, log₁₀ 2.33 ± 1.62, log₁₀ 0.62 ± 0.57 and log₁₀ -0.07 ± 0.73 in the tea tree oil, alcohol, benzalkonium chloride and control groups, respectively (F = 91.71, p < .001).
• No significant changes were noted for skin moisture, skin dryness, or skin exfoliation.

Overall, results of the study confirm the efficacy of tea tree oil as a natural antimicrobial. Besides performing at a similar level to alcohol, it also provided a stronger disinfection than the bezalkonium chloride treatment. Limitations of the study include solely measuring microbial amounts through adenosine triphosphate testing, which can often misrepresent the actual degree of contamination present. Future studies should explore the efficacy of tea tree oil at different levels, considering the 10% tea tree oil treatment used in the study is at a higher percentage rate that is not always cost effective and practical.

Source: Youn, Bock‐Hui, Yeon‐Suk Kim, Seungmin Yoo, and Myung‐Haeng Hur. “Antimicrobial and hand hygiene effects of Tea Tree Essential Oil disinfectant: A randomised control trial.” International Journal of Clinical Practice 75, no. 8 (2021): e14206.

© 2021 John Wiley & Sons Ltd

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Posted May 12, 2022.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

1. Banik S, Melanthota SK, Vannathan AA, Mahato KK, Mal SS, Mazumder N. Spectroscopic methods for assessment of hand sanitizers. Chem Zvesti. Apr 25 2022:1-12. doi:10.1007/s11696-022-02208-x
2. Escudero-Abarca BI, Goulter RM, Manuel CS, et al. Comparative Assessment of the Efficacy of Commercial Hand Sanitizers Against Human Norovirus Evaluated by an in vivo Fingerpad Method. Front Microbiol. 2022;13:869087. doi:10.3389/fmicb.2022.869087
3. Agrawal A, Mukhopadhyay S. Hiding in Plain Sight: The Unaddressed Risk of Self-Harm With Alcohol-Based Hand Sanitizers. Indian J Psychol Med. Nov 2021;43(6):561-562. doi:10.1177/02537176211042197
4. Manuel CS, Yeomans DJ, Williams JA, et al. Presence of unsafe chemical impurities, accelerated evaporation of alcohol, and lack of key labeling requirements are risks and concerns for some alcohol-based hand sanitizers and dispenser practices during the COVID-19 pandemic. PLoS One. 2022;17(3):e0265519. doi:10.1371/journal.pone.0265519
5. Zhu L, Machmudah S, Wahyudiono, Kanda H, Goto M. Reduced-Pressure Process for Fabricating Tea Tree Oil-Polyvinylpyrrolidone Electrospun Fibers. Polymers (Basel). Feb 15 2022;14(4)doi:10.3390/polym14040743
6. Borotová P, Galovičová L, Vukovic NL, Vukic M, Tvrdá E, Kačániová M. Chemical and Biological Characterization of Melaleuca alternifolia Essential Oil. Plants (Basel). Feb 20 2022;11(4)doi:10.3390/plants11040558
7. Wróblewska M, Szymańska E, Winnicka K. The Influence of Tea Tree Oil on Antifungal Activity and Pharmaceutical Characteristics of Pluronic(®) F-127 Gel Formulations with Ketoconazole. Int J Mol Sci. Oct 20 2021;22(21)doi:10.3390/ijms222111326