|Preferred IUPAC name|
| Systematic IUPAC name |
|Other names |
2-Isopropyl-5-methylphenol, isopropyl-m-cresol, 1-methyl-3-hydroxy-4-isopropylbenzene, 3-methyl-6-isopropylphenol, 5-methyl-2-(1-methylethyl)phenol, 5-methyl-2-isopropyl-1-phenol, 5-methyl-2-isopropylphenol, 6-isopropyl-3-methylphenol, 6-isopropyl-m-cresol, Apiguard, NSC 11215, NSC 47821, NSC 49142, thyme camphor, m-thymol, and p-cymen-3-ol
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||150.221 g·mol−1|
|Melting point||49 to 51 °C (120 to 124 °F; 322 to 324 K)|
|Boiling point||232 °C (450 °F; 505 K)|
|0.9 g/L (20 °C)|
Refractive index (nD)
|QP53AX22 ( WHO )|
|H302, H314, H411|
|P260, P264, P270, P273, P280, P301+P312, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P363, P391, P405, P501|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
(what is ?)
Thymol (also known as 2-isopropyl-5-methylphenol, IPMP), C10H14O, is a natural monoterpenoid phenol derivative of p-Cymene, isomeric with carvacrol, found in oil of thyme, and extracted from Thymus vulgaris (common thyme), ajwain, and various other plants as a white crystalline substance of a pleasant aromatic odor and strong antiseptic properties. Thymol also provides the distinctive, strong flavor of the culinary herb thyme, also produced from T. vulgaris. Thymol is only slightly soluble in water at neutral pH, but it is extremely soluble in alcohols and other organic solvents. It is also soluble in strongly alkaline aqueous solutions due to deprotonation of the phenol. Its dissociation constant (pKa) is 10.59±0.10. Thymol absorbs maximum UV radiation at 274 nm.
Thymol is produced by the alkylation of m-cresol and propene:
Ancient Egyptians used thyme for embalming.The ancient Greeks used it in their baths and burned it as incense in their temples, believing it was a source of courage. The spread of thyme throughout Europe was thought to be due to the Romans, as they used it to purify their rooms and to "give an aromatic flavour to cheese and liqueurs". In the European Middle Ages, the herb was placed beneath pillows to aid sleep and ward off nightmares. In this period, women also often gave knights and warriors gifts that included thyme leaves, because it was believed to bring courage to the bearer. Thyme was also used as incense and placed on coffins during funerals, because it was supposed to ensure passage into the next life.
The bee balms Monarda fistulosa and Monarda didyma , North American wildflowers, are natural sources of thymol. The Blackfoot Native Americans recognized these plants' strong antiseptic action and used poultices of the plants for skin infections and minor wounds. A tisane made from them was also used to treat mouth and throat infections caused by dental caries and gingivitis.
Thymol was first isolated by German chemist Caspar Neumann in 1719.In 1853, French chemist Alexandre Lallemand named thymol and determined its empirical formula. Thymol was first synthesized by Swedish chemist Oskar Widman in 1882.
An in vitro study found thymol and carvacrol to be highly effective in reducing the minimum inhibitory concentration of several antibiotics against zoonotic pathogens and food spoilage bacteria such as Salmonella typhimurium SGI 1 and Streptococcus pyogenes ermB.In vitro studies have found thymol to be useful as an antifungal against food spoilage and bovine mastitis. Thymol demonstrates in vitro post-antibacterial effect against the test strains E. coli and P. aeruginosa (gram negative), and Staphylococcus aureus and B. cereus (gram positive). This antibacterial activity is caused by inhibiting growth and lactate production, and by decreasing cellular glucose uptake.
Thyme essential oil is useful in preservation of food. The antibacterial properties of thymol, a major part of thyme essential oil, as well as other constituents, are in part associated with their lipophilic character, leading to accumulation in bacterial membranes and subsequent membrane-associated events, such as energy depletion.
The antifungal nature of thymol against some fungi that are pathogenic to plants is due to its ability to alter the hyphal morphology and cause hyphal aggregates, resulting in reduced hyphal diameters and lyses of the hyphal wall.
Thymol during the 1910s was the treatment of choice for hookworm infection in the United States.People of the Middle East continue to use za'atar, a delicacy made with large amounts of thyme, to reduce and eliminate internal parasites. It is also used as a preservative in halothane, an anaesthetic, and as an antiseptic in mouthwash. When used to reduce plaque and gingivitis, thymol has been found to be more effective when used in combination with chlorhexidine than when used purely by itself. Thymol is also the active antiseptic ingredient in some toothpastes, such as Johnson & Johnson's Euthymol. Thymol has been used to successfully control varroa mites and prevent fermentation and the growth of mold in bee colonies. Thymol is also used as a rapidly degrading, non-persisting pesticide. Thymol can also be used as a medical disinfectant and general purpose disinfectant.
In 2009, the U.S. Environmental Protection Agency (EPA) reviewed the research literature on the toxicology and environmental impact of thymol and concluded that "thymol has minimal potential toxicity and poses minimal risk".
Studies have shown that hydrocarbon monoterpenes and thymol in particular degrade rapidly (DT50 16 days in water, 5 days in soil) in the environment and are, thus, low risks because of rapid dissipation and low bound residues, supporting the use of thymol as a pesticide agent that offers a safe alternative to other more persistent chemical pesticides that can be dispersed in runoff and produce subsequent contamination.
Media related to Thymol at Wikimedia Commons
Oregano is a species of flowering plant in the mint family Lamiaceae. It was native to the Mediterranean region, but widely naturalised elsewhere in the temperate Northern Hemisphere.
Thyme is the herb of some members of the genus Thymus of aromatic perennial evergreen herbs in the mint family Lamiaceae. Thymes are relatives of the oregano genus Origanum, with both plants being mostly indigenous to the Mediterranean region. Thymes have culinary, medicinal, and ornamental uses, and the species most commonly cultivated and used for culinary purposes is Thymus vulgaris.
An essential oil is a concentrated hydrophobic liquid containing volatile chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the oil of the plant from which they were extracted, such as oil of clove. An essential oil is essential in the sense that it contains the essence of the plant's fragrance—the characteristic fragrance of the plant from which it is derived. The term "essential" used here does not mean indispensable or usable by the human body, as with the terms essential amino acid or essential fatty acid, which are so called because they are nutritionally required by a living organism.
An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals are used against fungi. They can also be classified according to their function. Agents that kill microbes are microbicides, while those that merely inhibit their growth are called bacteriostatic agents. The use of antimicrobial medicines to treat infection is known as antimicrobial chemotherapy, while the use of antimicrobial medicines to prevent infection is known as antimicrobial prophylaxis.
Phytochemistry is the study of phytochemicals, which are chemicals derived from plants. Phytochemists strive to describe the structures of the large number of secondary metabolites found in plants, the functions of these compounds in human and plant biology, and the biosynthesis of these compounds. Plants synthesize phytochemicals for many reasons, including to protect themselves against insect attacks and plant diseases. The compounds found in plants are of many kinds, but most can be grouped into four major biosynthetic classes: alkaloids, phenylpropanoids, polyketides, and terpenoids.
Monarda is a genus of flowering plants in the mint family, Lamiaceae. The genus is endemic to North America. Common names include bergamot, bee balm, horsemint, oswego tea, the first inspired by the fragrance of the leaves, which is reminiscent of bergamot orange. The genus was named for the Spanish botanist Nicolás Monardes, who wrote a book in 1574 describing plants of the New World.
Origanum dictamnus, the dittany of Crete, Cretan dittany or hop marjoram, is a tender perennial plant that grows 20–30 cm high. It is known in Greek as δίκταμο or in the Cretan dialect as έρωντας. It is a therapeutic and aromatic plant that grows wild only on the mountainsides and gorges of the Greek island of Crete. It is widely used for food flavouring and medicinal purposes, in addition to featuring as an ornamental plant in gardens. This small, lanate shrub is easily recognised by the distinctive soft, woolly covering of white-grey hair on its stems and round green leaves, giving it a velvety texture. Tiny rose-pink flowers surrounded by brighter purple-pink bracts add an exuberant splash of colour to the plant in summer and autumn. The dittany is classified as vulnerable on the IUCN Red List of Threatened Plant Species 1997.
A chemotype is a chemically distinct entity in a plant or microorganism, with differences in the composition of the secondary metabolites. Minor genetic and epigenetic changes with little or no effect on morphology or anatomy may produce large changes in the chemical phenotype. Chemotypes are often defined by the most abundant chemical produced by that individual and the concept has been useful in work done by chemical ecologists and natural product chemists. With respect to plant biology, the term "chemotype" was first coined by Rolf Santesson and his son Johan in 1968, defined as, "...chemically characterized parts of a population of morphologically indistinguishable individuals."
Carvacrol, or cymophenol, C6H3(CH3)(OH)C3H7, is a monoterpenoid phenol. It has a characteristic pungent, warm odor of oregano.
Eucalyptol is a monoterpenoid. A colorless liquid, it is a bicyclic ether. Eucalyptol has a fresh mint-like smell and a spicy, cooling taste. It is insoluble in water, but miscible with organic solvents. Eucalyptol makes up 90% of eucalyptus oil. Eucalyptol forms crystalline adducts with hydrohalic acids, o-cresol, resorcinol, and phosphoric acid. Formation of these adducts is useful for purification.
Thymus herba-barona is a species of thyme native to Corsica, Sardinia, and Majorca. It is also sometimes known by the common name caraway thyme, as it has a strong scent similar to caraway, for which it can be used as a substitute in any recipe. It can be used in cuisine or as an evergreen ground cover plant for the garden.
Thymus vulgaris is a species of flowering plant in the mint family Lamiaceae, native to southern Europe from the western Mediterranean to southern Italy. Growing to 15–30 cm (6–12 in) tall by 40 cm (16 in) wide, it is a bushy, woody-based evergreen subshrub with small, highly aromatic, grey-green leaves and clusters of purple or pink flowers in early summer.
Eucalyptus oil is the generic name for distilled oil from the leaf of Eucalyptus, a genus of the plant family Myrtaceae native to Australia and cultivated worldwide. Eucalyptus oil has a history of wide application, as a pharmaceutical, antiseptic, repellent, flavouring, fragrance and industrial uses. The leaves of selected Eucalyptus species are steam distilled to extract eucalyptus oil.
Monoterpenes are a class of terpenes that consist of two isoprene units and have the molecular formula C10H16. Monoterpenes may be linear (acyclic) or contain rings (monocyclic and bicyclic). Modified terpenes, such as those containing oxygen functionality or missing a methyl group, are called monoterpenoids. Monoterpenes and monoterpenoids are diverse. They have relevance to the pharmaceutical, cosmetic, agricultural, and food industries.
Monarda fistulosa, the wild bergamot or bee balm, is a wildflower in the mint family Lamiaceae, widespread and abundant as a native plant in much of North America. This plant, with showy summer-blooming pink to lavender flowers, is often used as a honey plant, medicinal plant, and garden ornamental. The species is quite variable, and several subspecies or varieties have been recognized within it.
Thymus pannonicus, known by its common name Hungarian thyme or Eurasian thyme, is a perennial herbaceous plant, distributed in central and eastern Europe and Russia. It grows over open dry meadows, grasslands, and rocks.
Origanum onites, the Cretan oregano, Greek oregano, pot marjoram or Ellinikí rίgani in Greek, is a plant species in the genus Origanum found in Sicily, Greece and Turkey. It has similar flavors as oregano. Its essential oil can be distinguished from other species such as Greek oregano. It has antimicrobial activities.
Thymus zygis is a type of flowering plant in the family Lamiaceae native to the Iberian Peninsula and northern Morocco.
Lagoecia, wild cumin, is a genus of flowering plants in the family Apiaceae. It has only one species, Lagoecia cuminoides, native to the Mediterranean region and as far east as Iran. Its essential oil contains 72.83–94.76% thymol, quite a bit more than thyme itself.