Manuka (Leptospermum scoparium) Research

Latin Name: Leptospermum scoparium

Family: Myrtaceae

Manuka is in the same plant family as tea tree, but has a differing essential oil profile.  While there are many chemotypes of manuka, it is generally higher in sesquiterpenes than tea tree, and also contains the leptospermone constituent not typically found in tea tree.

RESEARCH

The listings of research below represent a compilation of scientific articles found on the species, with a very brief overview description of each article/study. Research found is catalogued by therapeutic action. This categorized compilation of research articles does not necessarily imply that there are adequate results to demonstrate safe and/or effective human use.

GENERAL

• Lis-Balchin, M. (2006). Aromatherapy Science: A guide for healthcare professionals. London: Pharmaceutical Press.
• Petersen, D. (2015). Aromatherapy Materia Medica.  Essential oil monographs.  American College of Healthcare Sciences
• A general overview on Leptospermum scoparium was provided.  From:  Stephens, J. M. C., Molan, P. C., & Clarkson, B. D. (2005). A review of Leptospermum scoparium (Myrtaceae) in New Zealand. New Zealand Journal of Botany, 43(2), 431-449.
• Pharmacological actions were assessed of Manuka, Kanuka, and Tea tree oils.  From:  Lis‐Balchin, M., Hart, S. L., & Deans, S. G. (2000). Pharmacological and antimicrobial studies on different tea‐tree oils (Melaleuca alternifolia, Leptospermum scoparium or Manuka and Kunzea ericoides or Kanuka), originating in Australia and New Zealand. Phytotherapy research, 14(8), 623-629.
• In a review of research, manuka honey has shown a variety of antimicrobial activities and may also help with wound healing. From: Carter, D. A., Blair, S. E., Cokcetin, N. N., Bouzo, D., Brooks, P., Schothauer, R., & Harry, E. J. (2016). Therapeutic manuka honey: no longer so alternative. Frontiers in microbiology, 7, 569.

ANTIMICROBIAL / ANTIBACTERIAL / ANTIVIRAL

• Manuka and kanuka essential oils showed antibacterial, antifungal, anti-inflammatory activity in vitro, and may be effective against human infectious microorganisms.  From:  Chen, C. C., Yan, S. H., Yen, M. Y., Wu, P. F., Liao, W. T., Huang, T. S., … & Wang, H. M. D. (2016). Investigations of kanuka and manuka essential oils for in vitro treatment of disease and cellular inflammation caused by infectious microorganisms. Journal of Microbiology, Immunology and Infection, 49(1), 104-111.
• Antibacterial activity of Australian tea tree, cajuput, niaouli, kanuka, manuka, and eucalyptus oil were assessed.  From:  Harkenthal, M., Reichling, J., Geiss, H. K., & Saller, R. (1999). Comparative study on the in vitro antibacterial activity of Australian tea tree oil, cajuput oil, niaouli oil, manuka oil, kanuka oil, and eucalyptus oil. Die Pharmazie, 54(6), 460-463.
• Oregano and manuka essential oils were antibacterial against 14 tested strains of S. aureus.  From:  Fratini, F., Mancini, S., Turchi, B., Friscia, E., Pistelli, L., Giusti, G., & Cerri, D. (2017). A novel interpretation of the Fractional Inhibitory Concentration Index: The case Origanum vulgare L. and Leptospermum scoparium JR et G. Forst essential oils against Staphylococcus aureus strains. Microbiological research, 195, 11-17.
• Manuka and tea tree oil had strong antibacterial activity against pathogenic and cariogenic mouth bacteria.  From:  Takarada, K., Kimizuka, R., Takahashi, N., Honma, K., Okuda, K., & Kato, T. (2004). A comparison of the antibacterial efficacies of essential oils against oral pathogens. Oral microbiology and immunology, 19(1), 61-64.
• The inhibitory activity of manuka oil against Herpes virus types 1 and 2 was demonstrated in vitro. From: Reichling, J., Koch, C., Stahl-Biskup, E., Sojka, C., & Schnitzler, P. (2005). Virucidal activity of a β-triketone-rich essential oil of Leptospermum scoparium (manuka oil) against HSV-1 and HSV-2 in cell culture. Planta medica, 71(12), 1123-1127.
• Non-peroxide antibacterial activity of New Zealand tea tree was assessed.  From:  Adams, C. J., Boult, C. H., Deadman, B. J., Farr, J. M., Grainger, M. N., Manley-Harris, M., & Snow, M. J. (2008). Isolation by HPLC and characterisation of the bioactive fraction of New Zealand manuka (Leptospermum scoparium) honey. Carbohydrate research, 343(4), 651-659.
• Antimicrobial activity of manuka, kanuka, and tea tree were assessed. From:  Lis‐Balchin, M., Hart, S. L., & Deans, S. G. (2000). Pharmacological and antimicrobial studies on different tea‐tree oils (Melaleuca alternifolia, Leptospermum scoparium or Manuka and Kunzea ericoides or Kanuka), originating in Australia and New Zealand. Phytotherapy research, 14(8), 623-629.
• Manuka honey showed antibacterial activity.  From:  Mavric, E., Wittmann, S., Barth, G., & Henle, T. (2008). Identification and quantification of methylglyoxal as the dominant antibacterial constituent of Manuka (Leptospermum scoparium) honeys from New Zealand. Molecular nutrition & food research, 52(4), 483-489.
• Manuka showed antimicrobial activity against Staph. Pseudintermedius in dogs.  From:  Song, C. Y., Nam, E. H., Park, S. H., & Hwang, C. Y. (2013). In vitro efficacy of the essential oil from Leptospermum scoparium (manuka) on antimicrobial susceptibility and biofilm formation in Staphylococcus pseudintermedius isolates from dogs. Veterinary dermatology, 24(4), 404-e87.
• Antibacterial activity of manuka honey was isolated.  From:  Weston, R. J., Mitchell, K. R., & Allen, K. L. (1999). Antibacterial phenolic components of New Zealand manuka honey. Food chemistry, 64(3), 295-301.
• Manuka, ylang ylang, vetiver, patchouli, cinnamon, and sandalwood essential oils provided varying noteworthy synergistic activities with other essential oils against microbes that cause acne in vitro.  From:  Orchard, A., van Vuuren, S. F., Viljoen, A. M., & Kamatou, G. (2018). The in vitro antimicrobial evaluation of commercial essential oils and their combinations against acne. International journal of cosmetic science, 40(3), 226-243.
• Manuka honey was antibacterial against Staphyloccal microbes associated with the digestive tract in vitro.  From:  Mannina, L., Sobolev, A. P., Coppo, E., Di Lorenzo, A., Nabavi, S. M., Marchese, A., & Daglia, M. (2016). Antistaphylococcal activity and metabolite profiling of manuka honey (Leptospermum scoparium L.) after in vitro simulated digestion. Food & function, 7(3), 1664-1670.
• Australian tea tree oil, cajuput, niaouli, lema, kanuka, and manuka showed antimicrobial activities against Staphylococcus aureus.  From:  Christoph, F., Stahl-Biskup, E., & Kaulfers, P. M. (2001). Death kinetics of Staphylococcus aureus exposed to commercial tea tree oils sl. Journal of Essential Oil Research, 13(2), 98-102.

​SKIN  / WOUNDS

• Topical application of manuka oil on mice was anti-photoaging, showing anti-inflammatory activity and suppressing the UV-B-induced increase in skin thickness and wrinkle grading. From:  Kwon, O. S., Jung, S. H., & Yang, B. S. (2013). Topical administration of manuka oil prevents UV-B irradiation-induced cutaneous photoaging in mice. Evidence-Based Complementary and Alternative Medicine, 2013.

ACNE

• Manuka, ylang ylang, vetiver, patchouli, cinnamon, and sandalwood essential oils provided varying noteworthy synergistic activities with other essential oils against microbes that cause acne in vitro.  From:  Orchard, A., van Vuuren, S. F., Viljoen, A. M., & Kamatou, G. (2018). The in vitro antimicrobial evaluation of commercial essential oils and their combinations against acne. International journal of cosmetic science, 40(3), 226-243.
• In this review of research, different essential oil blends were found in studies to by synergistically effective against the acne pathogens Staphylococcus epidermidis and Propionibacterium acnes. Blends that included manuka, vetiver, patchouli, cinnamon, and sandalwood were mentioned. From: Orchard, A., Van Vuuren, S. F., Viljoen, A. M., & Kamatou, G. (2018). The in vitro antimicrobial evaluation of commercial essential oils and their combinations against acne. International journal of cosmetic science, 40(3), 226-243.

ANTI-INFLAMMATORY

• Manuka and kanuka essential oils showed antibacterial, antifungal, anti-inflammatory activity in vitro, and may be effective against human infectious microorganisms.  From:  Chen, C. C., Yan, S. H., Yen, M. Y., Wu, P. F., Liao, W. T., Huang, T. S., … & Wang, H. M. D. (2016). Investigations of kanuka and manuka essential oils for in vitro treatment of disease and cellular inflammation caused by infectious microorganisms. Journal of Microbiology, Immunology and Infection, 49(1), 104-111.

DIGESTIVE AID

• Leptospermone from the essential oil of Leptospermum scoparium strongly inhibited the growth of C. difficile and C. perfringens human intestinal bacteria.  From:  Jeong, E. Y., Jeon, J. H., Kim, H. W., Kim, M. G., & Lee, H. S. (2009). Antimicrobial activity of leptospermone and its derivatives against human intestinal bacteria. Food chemistry, 115(4), 1401-1404.
• Manuka honey was antibacterial against Staphyloccal microbes associated with the digestive tract in vitro.  From:  Mannina, L., Sobolev, A. P., Coppo, E., Di Lorenzo, A., Nabavi, S. M., Marchese, A., & Daglia, M. (2016). Antistaphylococcal activity and metabolite profiling of manuka honey (Leptospermum scoparium L.) after in vitro simulated digestion. Food & function, 7(3), 1664-1670.

​SPASMOLYTIC

• Manuka and Kanuka oils induced a spasmolytic effect in guinea pig smooth muscle.  From:  LIS‐BALCHIN, M. A. R. I. A., & Hart, S. L. (1998). An Investigation of the Actions of the Essential oils of Manuka (Leptospermum scoparium) and Kanuka (Kunzea ericoides), Myrtaceae on Guinea‐pig Smooth Muscle. Journal of pharmacy and pharmacology, 50(7), 809-811.

ORAL HEALTH

• Neck and cancer patients who received radiation had delayed onset of mucositis and reduced pain and oral symptoms from gargling a blend with manuka and kanuka.  From:  Maddocks-Jennings, W., Wilkinson, J. M., Cavanagh, H. M., & Shillington, D. (2009). Evaluating the effects of the essential oils Leptospermum scoparium (manuka) and Kunzea ericoides (kanuka) on radiotherapy induced mucositis: a randomized, placebo controlled feasibility study. European Journal of Oncology Nursing, 13(2), 87-93.
• Manuka and tea tree oil had strong antibacterial activity against pathogenic and cariogenic mouth bacteria.  From:  Takarada, K., Kimizuka, R., Takahashi, N., Honma, K., Okuda, K., & Kato, T. (2004). A comparison of the antibacterial efficacies of essential oils against oral pathogens. Oral microbiology and immunology, 19(1), 61-64.
• This article reviews plants used in oral health and includes pomegranate, German chamomile, green tea, Diospyros mespiliformis, Diospyros lycioides, Salvadora persica, honey and propolis from the manuka tree, rhubarb, raisins, essential oils (thyme, cajuput, manuka, and verbena), probiotics and mushrooms. From: Chinsembu, K. C. (2016). Plants and other natural products used in the management of oral infections and improvement of oral health. Acta Tropica, 154, 6-18.

MOUTH COLD SORES

• The inhibitory activity of manuka oil against Herpes virus types 1 and 2 was demonstrated in vitro. From: Reichling, J., Koch, C., Stahl-Biskup, E., Sojka, C., & Schnitzler, P. (2005). Virucidal activity of a β-triketone-rich essential oil of Leptospermum scoparium (manuka oil) against HSV-1 and HSV-2 in cell culture. Planta medica, 71(12), 1123-1127.

INSECTICIDAL / PESTICIDAL

• Leptospermum scoparium was active against three species of mites.  From:  Jeong, E. Y., Kim, M. G., & Lee, H. S. (2009). Acaricidal activity of triketone analogues derived from Leptospermum scoparium oil against house‐dust and stored‐food mites. Pest management science, 65(3), 327-331.
• Manuka, clove, and oregano were larvicidal against a mosquitoe species.  From:  Muturi, E. J., Ramirez, J. L., Doll, K. M., & Bowman, M. J. (2017). Combined toxicity of three essential oils against Aedes aegypti (Diptera: Culicidae) larvae. Journal of medical entomology, 54(6), 1684-1691.
• Australian plants demonstrated varying degrees of insect (mosquito) repellency and included: eucalyptus, tea tree, cajuput, manuka, balm mint bush, fragonia, myrtle, cypress, and niaouli. From: Webb, C. E. (2014). Insect repellents derived from Australian plants and implications for public health messages. Insect repellents handbook, 213.
• The repellency of Austrailian plants of the Myrtaceae family is reviewed. From: Webb, C. E. (2014). Insect repellents derived from Australian plants and implications for public health messages. Insect repellents handbook, 213.

Compiled by: Kathy Sadowski

Updated: 1/21/2020