Carvacrol, or cymophenol, C₆H₃(CH₃)(OH)C₃H₇, is a

monoterpenoid 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 funct ...

phenol. It has a characteristic pungent, warm odor of oregano.

Natural occurrence

Carvacrol is present in the

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the o ...

of ''

Origanum vulgare Oregano (, ; ''Origanum vulgare'') 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. Oregano is a woody perennial pl ...

'' (oregano), oil of

thyme Thyme () is the herb (dried aerial parts) 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 indigenou ...

, oil obtained from pepperwort, and wild bergamot. The essential oil of

subspecies contains between 5% and 75% of carvacrol, while ''

Satureja ''Satureja'' is a genus of aromatic plants of the family Lamiaceae, related to rosemary and thyme. It is native to North Africa, southern and southeastern Europe, the Middle East, and Central Asia. A few New World species were formerly included ...

'' (savory) subspecies have a content between 1% and 45%. ''

Origanum majorana Marjoram (; ''Origanum majorana'') 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 ma ...

'' (marjoram) and

Dittany of Crete ''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'' (''díktamo'', cf. " dittany") or in the Cretan dialect as ''έ ...

are rich in carvacrol, 50% and 60–80% respectively. It is also found in

tequila Tequila (; ) is a liquor, distilled beverage made from the Agave tequilana, blue agave plant, primarily in the area surrounding the city of Tequila, Jalisco, Tequila northwest of Guadalajara, Jalisco, Guadalajara, and in the Jaliscan Highlands ...

and ''

Lippia graveolens ''Lippia graveolens'', a species of flowering plant in the verbena or vervain family, Verbenaceae, is native to the southwestern United States (Texas and southern New Mexico), Mexico, and Central America as far south as Nicaragua. Common names i ...

'' (Mexican oregano) in the

verbena ''Verbena'' (), also known as vervain or verveine, is a genus in the family Verbenaceae. It contains about 150 species of annual and perennial herbaceous or semi-woody flowering plants. The majority of the species are native to the Americas a ...

family.

Sources

* ''

Monarda didyma ''Monarda didyma'', the crimson beebalm, scarlet beebalm, scarlet monarda, Eau-de-Cologne plant, Oswego tea, or bergamot, is an aromatic herb in the family Lamiaceae, native to eastern North America from Maine west to Ontario and Minnesota, and ...

'' * ''

Nigella sativa ''Nigella sativa'' (black caraway, also known as black cumin, nigella, kalonji or siyahdaneh) is an annual flowering plant in the family Ranunculaceae, native to eastern Europe (Bulgaria and Romania) and Western Asia (Cyprus, Turkey, Iran and Ir ...

'' * '' Origanum compactum'' * ''

Origanum dictamnus ''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'' (''díktamo'', cf. " dittany") or in the Cretan dialect as ''έ ...

'' * '' Origanum microphyllum'' * ''

Origanum onites ''Origanum onites'', the Cretan oregano, Greek oregano, pot marjoram or Ellinikí rίgani in Greek (Ελληνική ρίγανη), is a plant species in the genus ''Origanum'' found in Sicily, Greece and Turkey. It has similar flavors as oregan ...

'' * '' Origanum scabrum'' * ''

Origanum syriacum ''Origanum syriacum''; syn. ''Majorana syriaca'' (also ''Origanum maru'', although this primarily refers to a hybrid of ''O. syriacum''), bible hyssop, Biblical-hyssop, Lebanese oregano or Syrian oregano, is an aromatic perennial herb in the mint ...

'' * ''

Plectranthus amboinicus ''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 ...

'' * '' Thymus glandulosus'' * '' Lavandula multifida'' * '' Origanum minutiflorum'' * ''

Satureja thymbra ''Satureja thymbra'', commonly known as savory of Crete, whorled savory, pink savory, and Roman hyssop ( Arabic: ''za'atar rumi''; ''za'atar franji''), is a perennial-green dwarf shrub of the family Lamiaceae, having strongly scented leaves, ende ...

Synthesis and derivatives

Carvacrol may be synthetically prepared by a number of routes. The fusion of cymol

sulfonic acid In organic chemistry, sulfonic acid (or sulphonic acid) refers to a member of the class of organosulfur compounds with the general formula , where R is an organic alkyl or aryl group and the group a sulfonyl hydroxide. As a substituent, it is kn ...

with caustic

potash Potash () includes various mined and manufactured salts that contain potassium in water-soluble form.

results in desulfonation. By the action of

nitrous acid Nitrous acid (molecular formula ) is a weak and monoprotic acid known only in Solution (chemistry), solution, in the gas phase and in the form of nitrite () salts. Nitrous acid is used to make diazonium salts from amines. The resulting diazoni ...

on 1-methyl-2-amino-4-propyl

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, ...

, one effects diazotization. Prolonged heating of

camphor Camphor () is a waxy, colorless solid with a strong aroma. It is classified as a terpenoid and a cyclic ketone. It is found in the wood of the camphor laurel ('' Cinnamomum camphora''), a large evergreen tree found in East Asia; and in the k ...

and

iodine Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...

carvone Carvone is a member of a family of chemicals called terpenoids. Carvone is found naturally in many essential oils, but is most abundant in the oils from seeds of caraway (''Carum carvi''), spearmint (''Mentha spicata''), and dill. Uses Both c ...

with glacial

phosphoric acid Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, w ...

have also been demonstrated. The

dehydrogenation In chemistry, dehydrogenation is a chemical reaction that involves the removal of hydrogen, usually from an organic molecule. It is the reverse of hydrogenation. Dehydrogenation is important, both as a useful reaction and a serious problem. At ...

with a palladium-carbon catalyst has been established. It has also been prepared by

transalkylation In organic chemistry, transalkylation is a chemical reaction involving the transfer of an alkyl group from one organic compound to another. The reaction is used for the transfer of methyl and ethyl groups between benzene rings. This is of particul ...

of isopropylated

cresol Cresols (also hydroxytoluene or cresylic acid) are a group of aromatic organic compounds. They are widely-occurring phenols (sometimes called ''phenolics'') which may be either natural or manufactured. They are also categorized as methylphenol ...

s. It is extracted from Origanum oil by means of a 50% potash solution. It is a thick oil that sets at 20 °C to a mass of crystals of melting point 0 °C, and boiling point 236–237 °C. Oxidation with

ferric chloride Iron(III) chloride is the inorganic compound with the formula . Also called ferric chloride, it is a common compound of iron in the +3 oxidation state. The anhydrous compound is a crystalline solid with a melting point of 307.6 °C. The col ...

converts it into dicarvacrol, whilst

phosphorus pentachloride Phosphorus pentachloride is the chemical compound with the formula PCl5. It is one of the most important phosphorus chlorides, others being PCl3 and POCl3. PCl5 finds use as a chlorinating reagent. It is a colourless, water-sensitive and moist ...

transforms it into chlorcymol.

Antimicrobial effects

In vitro, carvacrol has

antimicrobial 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 ar ...

activity against 25 different phytopathogenic bacteria and strains including: ''

Cladosporium herbarum ''Cladosporium herbarum'' is a common fungus found worldwide in organic and inorganic matter. It is efficiently distributed in the air, where it exists as the most frequently occurring fungal species. It can grow over a wide range of temperature ...

'', '' Penicillium glabrum'', ''

Pseudomonas syringae ''Pseudomonas syringae'' is a rod-shaped, Gram-negative bacterium with polar flagella. As a plant pathogen, it can infect a wide range of species, and exists as over 50 different pathovars, all of which are available to researchers from intern ...

,'' and fungi such as ''

Fusarium verticillioides ''Fusarium verticillioides'' is the most commonly reported fungal species infecting maize (''Zea mays''). ''Fusarium verticillioides'' is the accepted name of the species, which was also known as ''Fusarium moniliforme''. The species has also bee ...

/F. moniliforme'', '' Rhizoctonia solani/R. solani'', ''

Sclerotinia sclerotiorum ''Sclerotinia sclerotiorum'' is a plant pathogenic fungus and can cause a disease called white mold if conditions are conducive. ''S. sclerotiorum'' can also be known as cottony rot, watery soft rot, stem rot, drop, crown rot and blossom blight. ...

'', and ''

Phytophthora capsici ''Phytophthora capsici'' is an oomycete plant pathogen that causes blight and fruit rot of peppers and other important commercial crops. It was first described by L. Leonian at the New Mexico State University Agricultural Experiment Station in ...

''.

Compendial status

British Pharmacopoeia The ''British Pharmacopoeia'' (''BP'') is the national pharmacopoeia of the United Kingdom. It is an annually published collection of quality standards for medicinal substances in the UK, which is used by individuals and organisations involve ...

Notes and references

{{Authority control Natural phenols Monoterpenes Alkylphenols Isopropyl compounds