5+ Proven Reasons Clove Essential Oil Has Amazing Health Properties
Recently, clove essential oil has become a new addition to my “go-to-oils” to diffuse. I have written previously on clove essential oil, but was re-inspired by its awesomeness by a recent blog that I posted on my Facebook page. This article is jam-packed with scientific references, and as I sifted through them, I became intrigued by this journal review on clove. It encouraged me to put my nose to PubMed and sniff out further information on this essential oil (pun intended). So, below I share with you my geeking out on the history, biochemistry, properties, and actions of clove (Syzygium aromaticum) essential oil.
Clove is a famous spice used in world cuisines. Its name is derived from the French clou, a nail, due to its shape resembling small irregular nails. Cloves are aromatic dried flower buds from an evergreen tree belonging to the family Myrtaceae (myrtle). It is native to Indonesia but is also grown in other countries, most recently, in Turkey. In fact, a recent study found the clove bud oil grown in Turkey was similar in constituents to the native cultivators.
Natural Standard’s professional monograph states:
Clove is widely cultivated in Indonesia, Sri Lanka, Madagascar, Tanzania, and Brazil. It is used in limited amounts in food products, and is used as a fragrance, flavoring agent, antiseptic, and local anesthetic. Clinical trials assessing clove as a monotherapy are limited; however, the expert panel German Commission E has approved the use of clove as a topical antiseptic and anesthetic.
Clove essential oil and/or its main component eugenol is well-known in dentistry. It has been studied for its use in easing discomfort, microbe-inhibition, and in application of formation of cement for teeth when used with zinc oxide. One in vitro study showed clove may prevent decalcification from the dental erosion caused by apple juice.
There are three essential oils clove species, specifically clove bud oil, clove stem oil, and clove leaf oil. All have different properties and compositions. It is believed clove bud oil may be the highest quality; therefore, it is the most expensive. It contains high amounts of eugenol (80-90%) and eugenol acetate (15%) and beta caryophyllene (5-12%). Of course, its constituents and compounds will vary based on genetic factors, climate, soil, distillation, and farming techniques of the plant. Extraction is also a factor. For example, one study reported that clove oil extracted with n-hexane had a somewhat smaller percentage of eugenol (71.56%).
A Little More on the Biochemistry of Clove Essential Oil
Eugenol is a type of phenylpropanoid. Plants form these compounds as defense against stresses such as infections, wounding, UV irradiation, exposure to ozone, pollutants, and herbivores. These compounds have been shown to have many different and health-promoting effects.
I’ve previously discussed the power of these secondary metabolites which are parent molecules to many varieties of plant polyphenols (including phenolic acids and esters, flavonoids, isoflavonoids, stilbenes, coumarins, curcuminoids, lignans, etc.) Due to the fact that polyphenols are not well- absorbed through diet or supplements, application with essential oils may be a more potent method to receive their benefits.
Some of the Actions of Clove Essential Oil- A Quick Summary
According to a 2007 review from Phytotherapy Research clove essential oil has a variety of actions. These include microbe-inhibiting, antioxidant protection, inflammation modulation, critter repelling, and easing of discomfort. Here is the summary from the abstract:
The essential oil extracted from the dried flower buds of clove, Eugenia caryophyllata L. Merr. & Perry (Myrtaceae), is used as a topical application to relieve pain and to promote healing and also finds use in the fragrance and flavouring industries. The main constituents of the essential oil are phenylpropanoids such as carvacrol, thymol, eugenol and cinnamaldehyde. The biological activity of Eugenia caryophyllata has been investigated on several microorganisms and parasites, including pathogenic bacteria, Herpes simplex and hepatitis C viruses. In addition to its antimicrobial, antioxidant, antifungal and antiviral activity, clove essential oil possesses antiinflammatory, cytotoxic, insect repellent and anaesthetic properties. This short review addresses the chemical composition and biological effects of clove essential oil, and includes new results from GC/MS analysis and a study of its antimicrobial activity against a large number of multi-resistant Staphylococcus epidermidis isolated from dialysis biomaterials.
More on the Actions of Clove Essential Oil
1. Microbe inhibition
- An in vitro study demonstrated clove’s action against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa.
- A review in Food Control (2011) highlighted the properties of essential oils as a means to prevent pathogenic microbes in our food supply. Another article discussed the use of clove and cinnamon oils for prevention of mold and fungus in different atmospheric conditions. Other in vitro articles have also shown bacterial and mold inhibition with clove, such as here and here.
- This in vivo and in vitro study reported on the use of various herbals, including clove, and stated, “Combinations of acyclovir with historically used herbal medicines showed strong combined therapeutic anti-HSV-1 activity in mice, especially reduction of virus yield in the brain.”
1. 5. Oral Care
This article was a review of 52 studies on the use of essential oils for its microbe-prevention properties in dentistry. It discussed concerns with antibiotic resistance and summarizes the effect and mode of action of clove as follows:
Main constituents found in the clove bud oil are the phenylpropanoids eugenol, eugenyl acetate, carvacrol, thymol, cinnamaldehyde, ?-caryophyllene, and 2-heptanone, when analyzed by gas chromatography.[33,34]
Eugenol is well-known for its therapeutic properties and is widely used in dentistry.
Antioxidant: When tested against tert-butylated hydroxytoluene, EO exhibited a very strong radical scavenging activity
Antifungal: It possesses antifungal activity. Clove oil and its main content eugenol also reduce the quantity of ergosterol, which is a specific component of fungal cell membrane. Germ tube formation by C. albicans is also inhibited
Antibacterial: It was found to possess inhibitory effect on multi-resistant Staphylococcus spp.
Attention Essential Oil BioChem Geek Lovers:
This above article is also a gem for reviewing the properties of lavender, lemon, peppermint (including biofilm prevention), cinnamon, tea tree, and eucalyptus oils. You may want to bookmark it for reference.
Another article tested clove oil and its constituents against oral bacteria in vitro and found clove oil and its main constituent eugenol offer protection from pathogenic critters found in the mouth.
2. Antioxidant power
This study reports on the antioxidant power of clove among 26 spices and this other study further supports clove’s antioxidant effect.
3. Soothing discomfort
One study reported on the beneficial effects of application of clove oil in canines and humans as compared to a topical analgesia.
4. Immune balancing
This study focused on various properties of eugenol and that it had anti-proliferative effects in vitro against certain tumor lines. (A thorough review of various phenylpropanoids in essential oils against tumor cells can be found here.) Finally, this study showed that eugenol may also prevent histamine responses in rats.
5. Outdoor Comfort
Legally, no essential oils can claim to be bug repellents. One article abstract reported the following:
The mosquito repellent activity of 38 essential oils from plants at three concentrations was screened against the mosquito Aedes aegypti under laboratory conditions using human subjects. On a volunteer’s forearm, 0.1 mL of oil was applied per 30 cm2 of exposed skin. When the tested oils were applied at a 10% or 50% concentration, none of them prevented mosquito bites for as long as 2 h, but the undiluted oils of Cymbopogon nardus (citronella), Pogostemon cablin (patchuli), Syzygium aromaticum (clove) and Zanthoxylum limonella (Thai name: makaen) were the most effective and provided 2 h of complete repellency. From these initial results, three concentrations (10%, 50% and undiluted) of citronella, patchouli, clove and makaen were selected for repellency tests against Culex quinquefasciatus and Anopheles dirus. As expected, the undiluted oil showed the highest protection in each case. Clove oil gave the longest duration of 100% repellency (2-4 h) against all three species of mosquito
Remember, essential oils have many actions due to their physiological, biochemical, and psychological effects. So, if you’re thinking clove may be too good to be true in all its actions, give a little skim here.
For a quick overview, this blog post on MedlinePlus reviews some of the main points discussed quite succinctly.
Hackler, H. The Healthy Spice Cabinet: 7 Healing Spices and 2 Recipes. Chopra.com. Available at: http://www.chopra.com/ccl/the-healthy-spice-cabinet-7-healing-spices-and-2-recipes. Accessed June 13, 2016.
Cortés-Rojas DF, de Souza CRF, Oliveira WP. Clove (Syzygium aromaticum): a precious spice. Asian Pacific Journal of Tropical Biomedicine. 2014;4(2):90-96. doi:10.1016/S2221-1691(14)60215-X http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3819475/
Natural Standard Database. Clove. Professional Monograph. https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=251
Alma MH, Erta M, Nitz S, Kollmannsberger H. Chemical composition and content of essential oil from the bud of cultivated Turkish clove (Syzygium aromaticum L.). Essential oil content, Turkish Clove. Bioresources; 2007. 2(2): 265-269.
Chaieb K, Hajlaoui H, Zmantar T, Kahla-Nakbi AB, Rouabhia M, Mahdouani K, Bakhrouf A. The chemical composition and biological activity of clove essential oil, Eugenia caryophyllata (Syzigium aromaticum L. Myrtaceae): a short review. Phytother Res. 2007 Jun;21(6):501-6.
Marya CM, Satija G, J. A, Nagpal R, Kapoor R, Ahmad A. In Vitro Inhibitory Effect of Clove Essential Oil and Its Two Active Principles on Tooth Decalcification by Apple Juice. International Journal of Dentistry. 2012;2012:759618. doi:10.1155/2012/759618.
Plant phenylpropanoids as emerging anti-inflammatory agents. Mini Rev Med Chem. 2011 Sep;11(10):823-35.
Symposium on ‘Plants as animal foods: a case of catch 22?’: Antimicrobial properties of plant secondary metabolites. Proceedings of the Nutrition Society. (2004),63: 621–629.
Nuñez L, Aquino MD. Microbicide activity of clove essential oil (Eugenia caryophyllata). Brazilian Journal of Microbiology. 2012;43(4):1255-1260. doi:10.1590/S1517-83822012000400003.
Tajkarimi M.M., Ibrahim S.A., Cliver D.O. Antimicrobial herb and spice compounds in food. Food Control. 2010;21:1199–2121.
Antimicrobial activity of cinnamon and clove oils under modified atmosphere conditions. Int J Food Microbiol. 2006 Mar 15;107(2):180-5. Epub 2005 Nov 2.
Antimicrobial activity of clove and rosemary essential oils alone and in combination. Phytother Res. 2007 Oct;21(10):989-94.
[The synergism of antifungals and essential oils against Candida spp. evaluated by a modified gradient-diffusion method]. [article in Polish]. Med Dosw Mikrobiol. 2011;63(2):163-9.
Kurokawa M, Nagasaka K, Hirabayashi T, et al. Efficacy of traditional herbal medicines in combination with acyclovir against herpes simplex virus type 1 infection in vitro and in vivo. Antiviral Res 1995;27:19-37.
Dagli N, Dagli R, Mahmoud RS, Baroudi K. Essential oils, their therapeutic properties, and implication in dentistry: A review. Journal of International Society of Preventive & Community Dentistry. 2015;5(5):335-340. doi:10.4103/2231-0762.165933.
Moon SE, Kim HY, Cha JD.Synergistic effect between clove oil and its major compounds and antibiotics against oral bacteria. Arch Oral Biol. 2011 Sep;56(9):907-16. doi: 10.1016/j.archoralbio.2011.02.005.
Saharkhiz MJ, Motamedi M, Zomorodian K, Pakshir K, Miri R, Hemyari K. Chemical Composition, Antifungal and Antibiofilm Activities of the Essential Oil of Mentha piperita L. ISRN Pharmaceutics. 2012;2012:718645. doi:10.5402/2012/718645.
Nassar MI. et al. Chemical constituents of clove (Syzygium aromaticum, Fam. Myrtaceae) and their antioxidant activity. Revista Latinoamericana de Química. 2007; 35(3):47. https://www.researchgate.net/publication/228357516_Chemical_constituents_of_clove_Syzygium_aromaticum_Fam_Myrtaceae_and_their_antioxidant_activity
Shan B, Cai YZ, Sun M, Corke H. Antioxidant capacity of 26 spice extracts and characterization of their phenolic constituents. J Agric Food Chem. 2005 Oct 5;53(20):7749-59.
Alqareer A, Alyahya A, Andersson L. The effect of clove and benzocaine versus placebo as topical anesthetics. J Dent. 2006 Nov;34(10):747-50. Epub 2006 Mar 13.
Carvalho AA, Andrade LN, de Sousa ÉBV, de Sousa DP. Antitumor Phenylpropanoids Found in Essential Oils. BioMed Research International. 2015;2015:392674. doi:10.1155/2015/392674.
Jaganathan, S. K. and Supriyanto, E. Antiproliferative and molecular mechanism of eugenol-induced apoptosis in cancer cells. Molecules. 2012;17(6):6290-6304.
Trongtokit Y, Rongsriyam Y, Komalamisra N, Apiwathnasorn C. Comparative repellency of 38 essential oils against mosquito bites. Phytother Res. 2005 Apr;19(4):303-9. http://www.ncbi.nlm.nih.gov/pubmed/16041723
Clove. Medlineplus. https://www.nlm.nih.gov/medlineplus/druginfo/natural/251.html