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Names | |
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Preferred IUPAC name 5-Methyl-2-(propan-2-yl)phenol [1] | |
Systematic IUPAC name 5-Methyl-2-(propan-2-yl)benzenol | |
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 | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
DrugBank | |
ECHA InfoCard | 100.001.768 |
EC Number |
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KEGG | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C10H14O | |
Molar mass | 150.221 g·mol−1 |
Density | 0.96 g/cm3 |
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) [2] | |
Refractive index (nD) | 1.5208 [3] |
Pharmacology | |
QP53AX22 ( WHO ) | |
Hazards | |
GHS labelling: | |
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Warning | |
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). |
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, [4] 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. [5] Thymol absorbs maximum UV radiation at 274 nm. [6]
Thymol is produced by the alkylation of m-cresol and propene: [7] [8]
A predicted method of biosynthesis of thymol in thyme and oregano begins with the cyclization of geranyl diphosphate by TvTPS2 to γ-terpinene. Oxidation by a cytochrome P450 in the CYP71D subfamily creates a dienol intermediate, which is then converted into a ketone by short-chain dehydrogenase. Lastly, keto-enol tautomerization gives thymol.
Ancient Egyptians used thyme for embalming. [10] 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". [11] In the European Middle Ages, the herb was placed beneath pillows to aid sleep and ward off nightmares. [12] 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. [13]
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. [14]
Thymol was first isolated by German chemist Caspar Neumann in 1719. [15] In 1853, French chemist Alexandre Lallemand [16] (1816-1886) named thymol and determined its empirical formula. [17] Thymol was first synthesized by Swedish chemist Oskar Widman [18] (1852-1930) in 1882. [19]
The conventional method of extracting is hydro-distillation (HD), but can also be extracted with solvent-free microwave extraction (SFME). In 30 minutes, SFME yields similar amounts of thymol with more oxygenated compounds than 4.5 hours of hydro-distillation at atmospheric pressures without the need for solvent. [20]
Thymol during the 1910s was the treatment of choice for hookworm infection in the United States. [21] [22] People of the Middle East continue to use za'atar, a delicacy made with large amounts of thyme, to reduce and eliminate internal parasites. [23] 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. [24] 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. [25] Thymol is also used as a rapidly degrading, non-persisting pesticide. [26] Thymol can also be used as a medical disinfectant and general purpose disinfectant. [27] Thymol is also used in the production of menthol through the hydrogenation of the aromatic ring. [28]
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". [43]
Studies have shown that hydrocarbon monoterpenes and thymol in particular degrade rapidly (DT50 16 days in water, 5 days in soil [26] ) in the environment and are, thus, low risks because of rapid dissipation and low bound residues, [26] 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. Though, there has been recent research into sustained released systems for botanically derived pesticides, such as using natural polysaccharides which would be biodegradable and biocompatible. [44]
Media related to Thymol at Wikimedia Commons
Marjoram is a cold-sensitive perennial herb or undershrub with sweet pine and citrus flavours. In some Middle Eastern countries, marjoram is synonymous with oregano, and there the names sweet marjoram and knotted marjoram are used to distinguish it from other plants of the genus Origanum. It is also called pot marjoram, although this name is also used for other cultivated species of Origanum.
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 a culinary herb consisting of the dried aerial parts of some members of the genus Thymus of flowering plants in the mint family Lamiaceae. Thymes are native to Eurasia and north Africa. Thymes have culinary, medicinal, and ornamental uses. The species most commonly cultivated and used for culinary purposes is Thymus vulgaris, native to SE Europe.
Coleus amboinicus, synonym Plectranthus amboinicus, is a semi-succulent perennial plant in the family Lamiaceae with a pungent oregano-like flavor and odor. Coleus amboinicus is considered to be native to parts of Africa, the Arabian Peninsula, and India, although it is widely cultivated and naturalized elsewhere in the tropics where it is used as a spice and ornamental plant. Common names in English include Indian borage, country borage, French thyme, Indian mint, Mexican mint, Cuban oregano, broad leaf thyme, soup mint, Spanish thyme. The species epithet, amboinicus refers to Ambon Island, in Indonesia, where it was apparently encountered and described by João de Loureiro (1717–1791).
The genus Thymus contains about 350 species of aromatic perennial herbaceous plants and subshrubs to 40 cm tall in the family Lamiaceae, native to temperate regions in Europe, North Africa and Asia. Thymus species are particularly concentrated in Iran, attributed to Iran's diverse climate and topographic/geographic location.
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, and oswego tea, the first being 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.
Summer savory is among the best known of the savory genus. It is an annual, but otherwise is similar in use and flavor to the perennial winter savory. It is used more often than winter savory, which has a slightly more bitter flavor.
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.
Caryophyllene, more formally (−)-β-caryophyllene (BCP), is a natural bicyclic sesquiterpene that is a constituent of many essential oils, especially clove oil, the oil from the stems and flowers of Syzygium aromaticum (cloves), the essential oil of Cannabis sativa, copaiba, rosemary, and hops. It is usually found as a mixture with isocaryophyllene and α-humulene, a ring-opened isomer. Caryophyllene is notable for having a cyclobutane ring, as well as a trans-double bond in a 9-membered ring, both rarities in nature.
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.
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 common oregano.It has antimicrobial activities.
γ-Terpinene synthase is an enzyme with systematic name geranyl-diphosphate diphosphate-lyase . This enzyme catalyses the following chemical reaction
2,5-Dimethoxy-p-cymene, or thymohydroquinone dimethyl ether, is a phytochemical found in the essential oils of plants within the family Asteraceae. These essential oils, which contain the compound as a major component of the oil, have antifungal, antibacterial, and insecticidal properties.
Thymus zygis is a type of flowering plant in the family Lamiaceae native to the Iberian Peninsula and northern Morocco.
Satureja thymbra, commonly known as savory of Crete, whorled savory, pink savory, and Roman hyssop, is a perennial-green dwarf shrub of the family Lamiaceae, having strongly scented leaves, native to Libya, southeastern Europe from Sardinia to Turkey; Cyprus, Lebanon, Israel and the Palestinian Authority. The plant is noted for its dark-green leaves which grow on numerous, closely compacted branches, reaching a height of 20–50 cm. The plant bears pink to purple flowers that blossom between March and June.
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.