Eugenol

Eugenol is a phenol, as found in basil, bay, clove, cinnamon leaf, marjoram, nutmeg, pimento, rose, and ylang ylang.  Clove bud (Eugenia caryophyllata) can be over 75% eugenol. It is a strong antimicrobial, analgesic, and anti-inflammatory, but could be toxic to the liver in excess.

Safety concerns

• Clove oil and the eugenol constituent were found to be highly cytotoxic to human skin cells.  From:  Prashar, A., Locke, I. C., & Evans, C. S. (2006). Cytotoxicity of clove (Syzygium aromaticum) oil and its major components to human skin cells. Cell Proliferation, 39(4), 241-248.

Links to Plants Containing Eugenol

Basil

Bay

Cinnamon

Clove

Nutmeg

RESEARCH

The listings of research below represent a compilation of scientific articles found on the topic, with a very brief overview description of each article/study.  This compilation of research articles does not necessarily imply that there are adequate results to demonstrate safe and/or effective human use of any herb listed.

ANTIMICROBIAL / ANTIFUNGAL / ANTIBACTERIAL / ANTIVIRAL

• Strong fumigant antifungal activities was demonstrated by ajowan (Trachyspermum ammi), and allspice (Pimenta dioica) oils and their thymol and eugenol constituents against the following three Aspergillus species: A. ochraceus, A. parasiticus, and A. niger.  From:  Kim, E., Oh, C. S., Koh, S. H., Kim, H. S., Kang, K. S., Park, P. S., … & Park, I. K. (2016). Antifungal activities after vaporization of ajowan (Trachyspermum ammi) and allspice (Pimenta dioica) essential oils and blends of their constituents against three Aspergillus species. Journal of Essential Oil Research, 28(3), 252-259.
• Basil (Ocimum basilicum) essential oil showed activity against eight important postharvest deteriorating fungi with the following constituents being significant: 1,8-cineole, linalool, camphor, α-terpineol, methyl chavicol, and eugenol.  From:  Barcelos, R. C., Jham, G. N., Dhingra, O. D., Mendonca, F. A., & Valente, V. M. (2013). Identification and Quantification of the Major Fungitoxic Components of the Brazilian Basil (Ocimum basilicum L.) Essential Oil. Journal of Food Research, 2(5), 124.
• The constituents of eugenol, carvacrol, thymol, p-cymene and γ-terpinene were effective against oral bacteria.  From:  Miladi, H., Zmantar, T., Kouidhi, B., Al Qurashi, Y. M. A., Bakhrouf, A., Chaabouni, Y., … & Chaieb, K. (2017). Synergistic effect of eugenol, carvacrol, thymol, p-cymene and γ-terpinene on inhibition of drug resistance and biofilm formation of oral bacteria. Microbial pathogenesis, 112, 156-163.
  
• With eugenol as the key constituent, O. basilicum and O. gratissimum essential oils from different locations showed chemical variation, antifungal activity, free radical scavenging capacity and anti-mycotoxicogenic property.  From:  Dambolena, J. S., Zunino, M. P., López, A. G., Rubinstein, H. R., Zygadlo, J. A., Mwangi, J. W., … & Kariuki, S. T. (2010). Essential oils composition of Ocimum basilicum L. and Ocimum gratissimum L. from Kenya and their inhibitory effects on growth and fumonisin production by Fusarium verticillioides. Innovative Food Science & Emerging Technologies, 11(2), 410-414.
• This mega analysis reviewed studies of essential oils as antibacterials in food.  Several effective constituents included carvacrol, thymol, eugenol, perillaldehyde, cinnamaldehyde and cinnamic acid.  They have minimum inhibitory concentrations with some having synergism such as carvacrol and p-cymene, cinnamaldehyde and eugenol, and between EO components and mild preservation methods.  From:  Burt, S. (2004). Essential oils: their antibacterial properties and potential applications in foods—a review. International journal of food microbiology, 94(3), 223-253.
• The study demonstrated Ocimum sanctum EO and eugenol as a plant based safe preservative against fungal spoilage of food.  From:  Kumar, A., Shukla, R., Singh, P., & Dubey, N. K. (2010). Chemical composition, antifungal and antiaflatoxigenic activities of Ocimum sanctum L. essential oil and its safety assessment as plant based antimicrobial. Food and chemical toxicology, 48(2), 539-543.
• Antibacterial abilities of 96 essential oils and their constituents were assessed. Marigold, ginger, jasmine, patchouli, gardenia, cedarwood, carrot seed, celery seed, mugwort, spikenard, and orange bitter oils along with the constituents of cinnamaldehyde, estragole, carvacrol, benzaldehyde, citral, thymol, eugenol, perillaldehyde, carvone R, and geranyl acetate were strongest against C. jejuni.  Those most active against E. coli were oregano, thyme, cinnamon, palmarosa, bay leaf, clove bud, lemon grass, and allspice oils and the constituents: carvacrol, cinnamaldehyde, thymol, eugenol, salicylaldehyde, geraniol, isoeugenol, citral, perillaldehyde, and estragole.  Those most active against L. monocytogenes were gardenia, cedarwood, bay leaf, clove bud, oregano, cinnamon, allspice, thyme, and patchouli and the constituents of cinnamaldehyde, eugenol, thymol, carvacrol, citral, geraniol, perillaldehyde, carvone S, estragole, and salicylaldehyde.  Those most active against S. enterica were thyme, oregano, cinnamon, clove bud, allspice, bay leaf, palmarosa, and marjoram oils as well as thymol, cinnamaldehyde, carvacrol, eugenol, salicylaldehyde, geraniol, isoeugenol, terpineol, perillaldehyde, and estragole.  From:  Friedman, M., Henika, P. R., & Mandrell, R. E. (2002). Bactericidal activities of plant essential oils and some of their isolated constituents against Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, and Salmonella enterica. Journal of Food Protection®, 65(10), 1545-1560.
• Carvacrol and eugenol had an anticandidal effect. From:  Chami, N., Bennis, S., Chami, F., Aboussekhra, A., & Remmal, A. (2005). Study of anticandidal activity of carvacrol and eugenol in vitro and in vivo. Oral microbiology and immunology, 20(2), 106-111.
• Clove oil and eugenol have considerable antifungal activity.  From:  Pinto, E., Vale-Silva, L., Cavaleiro, C., & Salgueiro, L. (2009). Antifungal activity of the clove essential oil from Syzygium aromaticum on Candida, Aspergillus and dermatophyte species. Journal of medical microbiology, 58(11), 1454-1462.
• Carrageenan, cineole, curcumin, and eugenol offered significant protection against herpes type 2 in mice.  From:  Bourne, K. Z., Bourne, N., Reising, S. F., & Stanberry, L. R. (1999). Plant products as topical microbicide candidates: assessment of in vitro and in vivo activity against herpes simplex virus type 2. Antiviral Research, 42(3), 219-226.
• Eugenol and nerolidol from Japanese cypress oil was topically antifungal against Microsporum gypseum on a guinea pig.  From:  Lee, S. J., Han, J. I., Lee, G. S., Park, M. J., Choi, I. G., Na, K. J., & Jeung, E. B. (2007). Antifungal effect of eugenol and nerolidol against Microsporum gypseum in a guinea pig model. Biological and Pharmaceutical Bulletin, 30(1), 184-188.
• Against oral bacteria, Australian tea tree, peppermint, and sage oil as well as the thymol and eugenol constituents were potent.  From:  Shapiro, S., Meier, A., & Guggenheim, B. (1994). The antimicrobial activity of essential oils and essential oil components towards oral bacteria. Oral microbiology and immunology, 9(4), 202-208.
• The following essential oils and their constituents in order of effectiveness were active against pathogens in apple juice:  against E. coli: carvacrol, oregano oil, geraniol, eugenol, cinnamon leaf oil, citral, clove bud oil, lemongrass oil, cinnamon bark oil, and lemon oil, and against S. enterica:  melissa oil, carvacrol, oregano oil, terpeineol, geraniol, lemon oil, citral, lemongrass oil, cinnamon leaf oil, and linalool. From:  Friedman, M., Henika, P. R., Levin, C. E., & Mandrell, R. E. (2004). Antibacterial activities of plant essential oils and their components against Escherichia coli O157: H7 and Salmonella enterica in apple juice. Journal of agricultural and food chemistry, 52(19), 6042-6048
• The antimicrobial activity of of thymol, carvacrol, limonene, cinnamaldehyde, and eugenol were assessed.  From:  Di Pasqua, R., Hoskins, N., Betts, G., & Mauriello, G. (2006). Changes in membrane fatty acids composition of microbial cells induced by addiction of thymol, carvacrol, limonene, cinnamaldehyde, and eugenol in the growing media. Journal of Agricultural and Food Chemistry, 54(7), 2745-2749.
• Ten minutes of exposure of vapors from essential oils Citrus bergamia, Eucalyptus globulus, and the constituents citronellol and eugenol were very active against the influenza virus. Vapors of Pelargonium graveolens, Cinnamomum zeylanicum, and Cymbopogon flexuosus were very active with 30 minutes of exposure. Further, Cinnamomum zeylanicum, Citrus bergamia, Cymbopogon flexuosus and Thymus vulgaris liquid essential oils displayed 100% inhibitory activity at a 3.1 µL/mL concentration. From: Vimalanathan, S., & Hudson, J. (2014). Anti-influenza virus activity of essential oils and vapors. American Journal of Essential Oils and Natural Products, 2(1), 47-53.
• Clove bud essential oil and its eugenol constituent reduced autophagy induction of tested strains of the flu. From: Dai, J. P., Zhao, X. F., Zeng, J., Wan, Q. Y., Yang, J. C., Li, W. Z., … & Li, K. S. (2013). Drug screening for autophagy inhibitors based on the dissociation of Beclin1-Bcl2 complex using BiFC technique and mechanism of eugenol on anti-influenza A virus activity. PloS one, 8(4).

ORAL HEALTH

• Oral antibacterial effectiveness of essential oils is reviewed.  Oils include: Achillea ligustica (yarrow), Baccharis dracunculifolia, Croton cajucara (sacaca), Cryptomeria japonica (Japanese red cedar), Coriandrum sativum (coriander), Eugenia caryophyllata (clove), Lippia sidoides, Ocimum americanum (basil), and Rosmarinus officinalis (rosemary). Constituents worth mentioning include menthol and eugenol.  From:  Freires, I. A., Denny, C., Benso, B., de Alencar, S. M., & Rosalen, P. L. (2015). Antibacterial activity of essential oils and their isolated constituents against cariogenic bacteria: a systematic review. Molecules, 20(4), 7329-7358.

ANTI-CANCER

• The main constituents of Ocimum basilicum essential oil: rosmarinic and caffeic acid and eugenol, isoeugenol and linalool were tested against four human cancer cell lines and have been found more effective than the corresponding extract or oil, with the isoeugenol being the major constituent of O. Basilicum essential oil acting as a cancer cell inhibitor.  From:  Zarlaha, A., Kourkoumelis, N., Stanojkovic, T. P., & Kovala-Demertzi, D. (2014). Cytotoxic activity of essential oil and extracts of Ocimum basilicum against human carcinoma cells.  Molecular docking study of isoeugenol as a potent cox and lox inhibitor.  J. Nanomat. Biostruc, 9(3), 907-917.

ANTI-PARASITE

• Ocimum sanctum and eugenol tested in vitro, showed potent anthelmintic activity.  From:  Asha, M. K., Prashanth, D., Murali, B., Padmaja, R., & Amit, A. (2001). Anthelmintic activity of essential oil of Ocimum sanctum and eugenol. Fitoterapia, 72(6), 669-670.
• Eugenol and S. aromaticum essential oil showed anti-giardia parasite activity.  From:  Machado, M., Dinis, A. M., Salgueiro, L., Custódio, J. B., Cavaleiro, C., & Sousa, M. C. (2011). Anti-Giardia activity of Syzygium aromaticum essential oil and eugenol: effects on growth, viability, adherence and ultrastructure. Experimental parasitology, 127(4), 732-739.

INSECTICIDAL / LARVICIDAL

• Against the yellow fever mosquito, pulegone, thymol, eugenol, trans-anithole, rosemary oil and citronellal showed high larvicidal activity. Eugenol, citronellal, thymol, pulegone, rosemary oil and cymene showed oviposition deterrent and/or repellent activities.  From:  Waliwitiya, R., Kennedy, C. J., & Lowenberger, C. A. (2009). Larvicidal and oviposition‐altering activity of monoterpenoids, trans‐anithole and rosemary oil to the yellow fever mosquito Aedes aegypti (Diptera: Culicidae). Pest management science, 65(3), 241-248.
• Thymol, eugenol, pulegone, alpha terpineol and citronellal demonstrated insecticidal abilities related to insect enzyme activity and flight motor response.   From:  Waliwitiya, R. (2011). Plant-derived compounds: acute toxicity, synergism, and effects on insect enzyme activity and flight motor responses (Doctoral dissertation, Science: Biological Sciences Department).
• Cinnamaldehyde and eugenol had an antibacterial effects against Paenibacillus larvae, a pest that affects honeybees.  From:  Gende, Liesel Brenda, et al. “Antimicrobial activity of cinnamon (Cinnamomum zeylanicum) essential oil and its main components against Paenibacillus larvae from Argentine.” Bulletin of insectology 61.1 (2008): 1.
• The study showed the following as possible termite fumigants:  Melaleuca dissitiflora, Melaleuca uncinata, Eucalyptus citriodora, Eucalyptus polybractea, Eucalyptus radiata, Eucalyptus dives, Eucalyptus globulus, Orixa japonica, Cinnamomum cassia, Allium cepa, Illicium verum, Evodia officinalis, Schizonepeta tenuifolia, Cacalia roborowskii, Juniperus chinensis var. horizontalis, Juniperus chinensis var. kaizuka, clove bud, and garlic as well as the constituents of Diallyl trisulfide was the most toxic, followed by diallyl disulfide, eugenol, diallyl sulfide, and β-caryophyllene.  From: Park, I. K., & Shin, S. C. (2005). Fumigant activity of plant essential oils and components from garlic (Allium sativum) and clove bud (Eugenia caryophyllata) oils against the Japanese termite (Reticulitermes speratus Kolbe). Journal of Agricultural and Food Chemistry, 53(11), 4388-4392.
• Pulegone, thymol, eugenol, trans-anithole, rosemary oil, citronellal, and cymene showed high larvicidal, oviposition deterrent, and/or repellent activities against the denge fever mosquito.  From:  Waliwitiya, R., Kennedy, C. J., & Lowenberger, C. A. (2009). Larvicidal and oviposition‐altering activity of monoterpenoids, trans‐anithole and rosemary oil to the yellow fever mosquito Aedes aegypti (Diptera: Culicidae). Pest management science, 65(3), 241-248.

ANTIOXIDANT

• Ocimum basilicum (basil) and Thymus vulgaris (thyme) demonstrated antioxidant powers with the following constituents showing the strongest activity: eugenol, thymol, carvacrol, and 4-allylphenol.  From:  Lee, S. J., Umano, K., Shibamoto, T., & Lee, K. G. (2005). Identification of volatile components in basil (Ocimum basilicum L.) and thyme leaves (Thymus vulgaris L.) and their antioxidant properties. Food Chemistry, 91(1), 131-137.
• 423 essential oils from 48 different botanical families were evaluated for their antioxidant activities as free radical scavenging agents.  Results identified oils of the botanical families Lamiaceae and Myrtaceae as the most effective antioxidants, with thymol, eugenol, and carvacrol being the major constituents. From:  Anthony, K. P., Deolu‐Sobogun, S. A., & Saleh, M. A. (2012). Comprehensive assessment of antioxidant activity of essential oils. Journal of food science, 77(8), C839-C843.
• Clove bud extract and its major aroma components, eugenol and eugenyl acetate demonstrated antioxidant activity.  From:  Lee, K. G., & Shibamoto, T. (2001). Antioxidant property of aroma extract isolated from clove buds [Syzygium aromaticum (L.) Merr. et Perry]. Food Chemistry, 74(4), 443-448.  L
• Of 25 essential oils tested, thyme and clove showed the highest antioxidant activity; indicated were their thymol and eugenol components..  Cinnamon, basil, bergamot, eucalyptus, chamomile, bitter orange, and aloe vera were also effective.  From:  Wei, A., & Shibamoto, T. (2010). Antioxidant/lipoxygenase inhibitory activities and chemical compositions of selected essential oils. Journal of agricultural and food chemistry, 58(12), 7218-7225

CHOLESTEROL LOWERING

• Total phenol content of essential oils was related to LDL antioxidant activity associated with cardiac heart disease.  Phenols included:  methylchavicol, anethol, p-cymen, apiole, cinnamic ether, carvacrol, thymol, p-cymene, vanillin, cuminol, and eugenol.  From:  Teissedre, P. L., & Waterhouse, A. L. (2000). Inhibition of oxidation of human low-density lipoproteins by phenolic substances in different essential oils varieties. Journal of Agricultural and Food Chemistry, 48(9), 3801-3805.

CARDIAC HEALTH

• Eugenol reduced platelet aggregation.  From:  Chen, S. J., Wang, M. H., & Chen, J. (1996). Antiplatelet and calcium inhibitory properties of eugenol and sodium eugenol acetate. General Pharmacology: The Vascular System, 27(4), 629-633.
• Eugenol and Isoeugenol found in nutmeg demonstrated platelet aggregation inhibition.  From:  Janssens, J., Laekeman, G. M., Pieters, L. A., Totte, J., Herman, A. G., & Vlietinck, A. J. (1990). Nutmeg oil: identification and quantitation of its most active constituents as inhibitors of platelet aggregation. Journal of ethnopharmacology, 29(2), 179-188.

ANTI-INFLAMMATORY

• Clove and eugenol exerted immunomodulatory/anti-inflammatory effects. From:  Bachiega, T. F., de Sousa, J. P. B., Bastos, J. K., & Sforcin, J. M. (2012). Clove and eugenol in noncytotoxic concentrations exert immunomodulatory/anti‐inflammatory action on cytokine production by murine macrophages. Journal of Pharmacy and Pharmacology, 64(4), 610-616
• Phytochemicals derived from spices can reduce inflammatory diseases.  These include:  turmeric (curcumin), red pepper (capsaicin), cloves (eugenol), ginger (gingerol), cumin, anise (anethol), fennel (anethol), basil (ursolic acid), rosemary (ursolic acid), garlic (diallyl sulfide, S-allylmercaptocysteine, and ajoene), and pomegranate (ellagic acid). From:  Aggarwal, B. B., & Shishodia, S. (2004). Suppression of the Nuclear Factor‐κB Activation Pathway by Spice‐Derived Phytochemicals: Reasoning for Seasoning. Annals of the New York Academy of Sciences, 1030(1), 434-441.
• Essential oil components were investigated to decrease harm caused by air pollution. The tested components, trans-anethole, estragole, eugenol and isoeugenol decreased the inflammatory response. From: Kfoury, M., Borgie, M., Verdin, A., Ledoux, F., Courcot, D., Auezova, L., & Fourmentin, S. (2016). Essential oil components decrease pulmonary and hepatic cells inflammation induced by air pollution particulate matter. Environmental chemistry letters, 14(3), 345-351.

PRESERVATIVE

• Essential oils of cilantro, coriander, cinnamon, oregano, rosemary, sage, clove, thyme, lemongrass, turmeric, mint, basil, and constituents of linalool, cinnamaldehyde, carvacrol, thymol, terpinene, cymene, alpha/beta pinene, bornyl acetate, camphor, 1,8-cineole, alpha terpeneol, geraniol, perrilaldehyde, and eugenol have demonstrated food preserving potential.  From:  Burt, S. (2004). Essential oils: their antibacterial properties and potential applications in foods—a review. International journal of food microbiology, 94(3), 223-253.

ANTI-ARTHRITIC

• Eugenol, a component of essential oil of cloves (Syzygium aromaticum) was anti-arthritic in mice.  From:  Grespan, R., Paludo, M., Lemos, H. D. P., Barbosa, C. P., Bersani-Amado, C. A., Dalalio, M. M. D. O., & Cuman, R. K. N. (2012). Anti-arthritic effect of eugenol on collagen-induced arthritis experimental model. Biological and Pharmaceutical Bulletin, 35(10), 1818-1820.

ANALGESIC

• Essential oil constituents with an analgesic activity are reviewed. Included are p-cymene, carvacrol, linalool, eugenol, menthol, alpha-bisabolol, cinnamaldehyde, citronellal, citronellol, citronellyl acetate, alpha-phelandrene, alpha-terpeneol, vanillin, borneol, myrtenol, pulegone, citral, thymol, limonene, nerol, anethole, nerolidol, carvone, farnesol, and beta-caryphyllene. From: Lima, T., da Nóbrega, F., de Brito, A., & de Sousa, D. (2017). Analgesic-like activity of essential oil constituents: an update. International journal of molecular sciences, 18(12), 2392.

RESPIRATORY

• Essential oil components were investigated to decrease harm caused by air pollution. The tested components, trans-anethole, estragole, eugenol and isoeugenol decreased the inflammatory response. From: Kfoury, M., Borgie, M., Verdin, A., Ledoux, F., Courcot, D., Auezova, L., & Fourmentin, S. (2016). Essential oil components decrease pulmonary and hepatic cells inflammation induced by air pollution particulate matter. Environmental chemistry letters, 14(3), 345-351.

Compiled by: Kathy Sadowski

Updated: 2/18/2020