Cloves

You might begrudge chomping down on a hard clove during dinner, but the aromatic flower buds are useful for more than just adding a distinctive flair to dishes. Cloves have extremely high antioxidant properties; in fact, one study that evaluated food from around the world found that cloves have the most antioxidants per gram weight of all foods sampled.

While you might not start adding cloves to all of your meals, supplementing with the spice is ideal for those looking for a boost in antioxidants.

Further research also suggests that cloves may be useful in the treatment of diabetes. Some studies have shown that the use of cloves can have a positive effect on complications due to diabetes and “normalize the lipid panel and also protect the kidney, liver and pancreas.”

Cloves are also being studied for their anti-microbial properties and their use in oral health. 

Active constituents
“Phenylpropanoids”: eugenol (4-allyl-2-methoxyphenol) and carvacrol, thymol, and cinnamaldehyde. Also contains: acetyleugenol and small quantities of gallic acid, sesquiterpenes, furfural, vanillin, and methyl-n-amyl ketoneeugenol, caryophyllene, humulene, and eugenyl acetate

AVAILABLE RESEARCH

Antioxidant

In this study, researchers procured food samples from countries worldwide and assayed the samples for their total antioxidant content using a modified version of the FRAP assay. The results found that cloves have the most antioxidants of all spices from this sample.

Carlsen, Monica H et al. “The total antioxidant content of more than 3100 foods, beverages, spices, herbs and supplements used worldwide.” Nutrition journal vol. 9 3. 22 Jan. 2010, doi:10.1186/1475-2891-9-3

This early cell line study demonstrated that clove may exhibit immunomodulatory properties in addition to preventing cellular energy induced by oxidative stress.

De Bona, Karine Santos et al. “Protective effect of gallic acid and Syzygium cumini extract against oxidative stress-induced cellular injury in human lymphocytes.” Drug and chemical toxicology vol. 39,3 (2016): 256-63. doi:10.3109/01480545.2015.1084631

This study demonstrated that the administration of clove is safe and suitable. The study also describes cloves’ “antioxidant, anti-inflammatory and anti-ulcerogenic activities.” With the administration of clove, “there was noted up-regulation of in vivo antioxidants such as superoxide dismutase, glutathione, and catalase.”

Issac, Abin et al. “Safety and anti-ulcerogenic activity of a novel polyphenol-rich extract of clove buds (Syzygium aromaticum L).” Food & function vol. 6,3 (2015): 842-52. doi:10.1039/c4fo00711e

This database contains information on antioxidant levels in selected foods, including cloves. The data finds that among other foods in this database, cloves rank high in their source of antioxidants.

Haytowitz, David B., and Seema Bhagwat. "USDA database for the oxygen radical absorbance capacity (ORAC) of selected foods, Release 2." US Department of Agriculture (2010): 10-48.

ADDITIONAL RESEARCH

There is ongoing research on the effects of cloves as it relates to the following health concerns:

Diabetes

This recent animal study in induced diabetic rats demonstrated that clove was able to normalize the lipid panel and also protect the kidney, liver and pancreas.

Chandran, Rahul et al. “Antidiabetic activity of Syzygium calophyllifolium in Streptozotocin-Nicotinamide induced Type-2 diabetic rats.” Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie vol. 82 (2016): 547-54. doi:10.1016/j.biopha.2016.05.036

Clove oil was capable of inhibiting the formation of advanced glycation end products and protein glycation. This study concluded that clove extract could be used for targeting diabetic complications.

Suantawee, Tanyawan et al. “Protein glycation inhibitory activity and antioxidant capacity of clove extract.” Journal of food science and technology vol. 52,6 (2015): 3843-50. doi:10.1007/s13197-014-1452-1

Oral health

A randomized double blind placebo controlled trial demonstrated that a toothpaste containing clove is beneficial with respect to oral and gingival health.

Jayashankar, S et al. “A randomised double-blind placebo-controlled study on the effects of a herbal toothpaste on gingival bleeding, oral hygiene and microbial variables.” The Ceylon medical journal vol. 56,1 (2011): 5-9. doi:10.4038/cmj.v56i1.2887

This review discusses the potential benefit of essential oils including clove oil as a therapeutic and preventative agent for various oral diseases.

Dagli, Namrata et al. “Essential oils, their therapeutic properties, and implication in dentistry: A review.” Journal of International Society of Preventive & Community Dentistry vol. 5,5 (2015): 335-40. doi:10.4103/2231-0762.165933

Anti-microbial properties

This study showed the antibacterial and anti-fungal properties of clove oil, especially when combined with other essential oils such as rosemary oil.

Fu, Yujie et al. “Antimicrobial activity of clove and rosemary essential oils alone and in combination.” Phytotherapy research : PTR vol. 21,10 (2007): 989-94. doi:10.1002/ptr.2179

AVAILABLE RESEARCH ON CONTRAINDICATIONS

Adverse reactions: contact dermatitis

In this study, 32 patients (Group 1) of 103 were selected on the basis of positive tests to one or more of possible indicators for allergy to spices. The test results found that “among the spices, the highest numbers of reactions were found to nutmeg (28%), paprika (19%) and cloves (12%) in the indicator-positive Group 1.”

van den Akker, T W et al. “Contact allergy to spices.” Contact dermatitis vol. 22,5 (1990): 267-72. doi:10.1111/j.1600-0536.1990.tb01594.x