Chemical Family: Phenols
analgesic 1, 2
antibacterial3, 4, 5, 6, 7, 8
antioxidant14, 15, 16, 17, 18,
liver protective15, 18
The analgesic action of thymol suggests effects in both skeletal and smooth muscle (1,2).
Thymol has a long-lasting antibacterial action (8), and has shown good efficacy against some antibiotic-resistant strains (5,6).
Thymol inhibits the growth of Cryptococcus neoformans, an opportunistic fungus that often causes problems in the last phase of AIDS (10).
The antimicrobial action of thymol is suggestive of therapeutic effects in infections of the skin, gums, throat, lungs, and GI tract.
The anti-inflammatory action of thymol involves inhibition of COX-1 and COX-2, and so is similar to medications such as aspirin and ibuprofen. Thymol also inhibits neutrophil chemotaxis (12).
Thymol is one of the most potent antioxidantessential oil constituents.
Its antioxidant action has been experimentally linked to inhibition of erythrocyte cell death, suggesting possible use in counteracting anemia or the impairment of microcirculation (19).
Experimental evidence suggests antioxidant-related protection that could minimise the side-effects of gamma radiation (16).
Thymol has shown in vitro antitumoral effects in cells for mouse melanoma (23).
Medicines that inhibit acetylcholinesterase are used in cases of cognitive dysfunction, for example people with Alzheimer's disease (26,27).
Thymol can cause skin irritation if used at 5% or more, though this is uncommon. At 1% it has never been known to cause any adverse skin reaction (Robert Tisserand, private communication).
Thymol inhibits platelet aggregation (29, 30). Essential oils high in thymol should therefore be avoided, especially in high or oral doses, before major surgery, and in anyone taking blood-thinning medication, or with blood coagulation issues.
Thymol is found in greatest quantity in the thymol chemotype of thyme oil (up to 74%), Monarda citrodora var citriodora (60%) and ajowan (up to 55%).
Thymol is isomeric with carvacrol, and their pharmacological properties are similar. They are invariably found together in essential oils.
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Haeseler G, Maue D, Grosskreutz J et al (2002) Voltage-dependent block of neuronal and skeletal muscle sodium channels by thymol and menthol. European Journal of Anaesthesiology 19:571-579.
Knobloch K, Pauli A, Iberl B et al (1989) Antibacterial and antifungal properties of essential oil components. Journal of Essential Oil Research 1:119-128
Mohammed MJ, Al-Bayati FA (2009) Isolation and identification of antibacterial compounds from Thymus kotschyanus aerial parts and Dianthus caryophyllus flower buds. Phytomedicine 16:632-637
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Alam K, Nagi MN, Badary OA et al (1999) The protective action of thymol against carbon tetrachloride hepatotoxicity in mice. Pharmacological Research 40:159-163
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Van Den Broucke CO, Lemli J A (1982) Antispasmodic activity ofOriganum compactum. Planta Medica 45:188-190
He L, Mo H, Hadisusilo S et al (1997) Isoprenoids suppress the growth of murine B16 melanomas in vitro and in vivo. Journal of Nutrition 127:668-674
Astani A, Reichling J, Schnitzler P (2010) Comparative study on the antiviral activity of selected monoterpenes derived from essential oils. Phytotherapy Research 24(5):673-679
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Jukic M, Politeo O, Maksimovic M, et al (2007) In vitroacetylcholinesterase inhibitory properties of thymol, carvacrol and their derivatives thymoquinone and thymohydroquinone. Phytotherapy Research 21(3):259-261
Orhan I, Kartal M, Kan Y, et al (2008) Activity of essential oils and individual components against acetyl- and butyrylcholinesterase. Zeitschrift fur Naturforschung C 63(7-8):547-553.
Muhlbauer RC, Lozano A, Palacio S et al (2003) Common herbs, essential oils, and monoterpenes potently modulate bone metabolism. Bone 32:372-380
Enomoto S, Asano R, Iwahori Y et al (2001) Hematological studies on black cumin oil from the seeds of Nigella sativa L. Biological & Pharmaceutical Bulletin 24:307-310
Okazaki et al (2002) Human platelet aggregation inhibitors from thyme (Thymus vulgaris L.). Phytotherapy Research 16(4):398-399