View source for Thymol

{{short description|Chemical compound found in plants including thyme}}
{{Distinguish|Melitracen{{!}}Thymeol|Thymine|Thiamine}}
{{Use American English|date=June 2025}}
{{cs1 config|name-list-style=vanc|display-authors=3}}
{{Use dmy dates|date=November 2020}}
{{chembox
| Watchedfields = changed
| verifiedrevid = 470609679
| ImageFile = Thymol2.svg
| ImageSize = 150
| ImageFile2 = Thymol3D.png
| ImageName = Thymol
| PIN = 5-Methyl-2-(propan-2-yl)phenol<ref name=iupac2013>{{cite book | title =  Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book) | publisher = The [[Royal Society of Chemistry]] | date = 2014 | location = Cambridge | page = 691 | doi = 10.1039/9781849733069-FP001 | isbn = 978-0-85404-182-4| chapter = Front Matter }}</ref>
| SystematicName = 5-Methyl-2-(propan-2-yl)benzenol
| OtherNames = 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
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 89-83-8
| IUPHAR_ligand = 2499
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 3J50XA376E
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = D01039
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 29411
| EC_number = 201-944-8
| PubChem = 6989
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 21105998
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB02513
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 27607
| InChI = 1/C10H14O/c1-7(2)9-5-4-8(3)6-10(9)11/h4-7,11H,1-3H3
| InChIKey = MGSRCZKZVOBKFT-UHFFFAOYAS
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C10H14O/c1-7(2)9-5-4-8(3)6-10(9)11/h4-7,11H,1-3H3
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = MGSRCZKZVOBKFT-UHFFFAOYSA-N
| SMILES = CC(C)c1ccc(C)cc1O
 }}
|Section2={{Chembox Properties
| C=10 | H=14 | O=1
| Density = 0.96 g/cm<sup>3</sup>
| MeltingPtC = 49 to 51
| BoilingPtC = 232
| Solubility = 0.9&nbsp;g/L (20&nbsp;°C)<ref>{{cite web |url=https://pubchem.ncbi.nlm.nih.gov/compound/thymol#section=Solubility |title=Thymol |publisher=PubChem |access-date=2016-04-01}}</ref>
| RefractIndex = 1.5208<ref>{{cite journal|last=Mndzhoyan |first=A. L. |title=Thymol from ''Thymus kotschyanus''. |journal=Sbornik Trudov Armyanskogo Filial. Akad. Nauk. |date=1940 |volume=1940 |pages=25–28}}</ref> 
 }}
|Section6={{Chembox Pharmacology
| ATCvet = yes
| ATCCode_prefix = P53
| ATCCode_suffix = AX22
 }}
|Section7={{Chembox Hazards
| GHSPictograms = {{GHS05}}{{GHS07}}{{GHS09}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|302|314|411}}
| PPhrases = {{P-phrases|260|264|270|273|280|301+312|301+330+331|303+361+353|304+340|305+351+338|310|321|330|363|391|405|501}}
 }}
}}

'''Thymol''' (also known as '''2-isopropyl-5-methylphenol''', IPMP), {{chem2|C10H14O}}, is a [[Monoterpene|monoterpenoid]], [[Phenols|phenol]] derivative of [[p-Cymene|''p''-cymene]], [[isomer]]ic with [[carvacrol]].<ref name="pubchem">{{cite web |title=Thymol |url=https://pubchem.ncbi.nlm.nih.gov/compound/6989 |publisher=PubChem, US National Library of Medicine |access-date=28 June 2025 |date=21 June 2025}}</ref> It occurs naturally in the oil of [[thyme]], and it is [[Liquid–liquid extraction|extracted]] from ''[[Thymus vulgaris]]'' (common thyme), [[ajwain]],<ref>{{Cite book|title=The book of spice: from anise to zedoary|last=O'Connell, John |date=27 August 2019 |isbn=978-1681774459 |publisher=Pegasus |location=New York |oclc=959875923}}</ref> and various other plants as a white [[crystal|crystalline]] substance of a pleasant [[Aromaticity|aromatic]] [[odor]].<ref name=pubchem/>

Thymol provides the distinctive flavor of the [[Herb|culinary herb]] thyme, also produced from ''T. vulgaris''.<ref name=pubchem/> Thymol is only slightly [[solubility|soluble]] in water at neutral [[pH]], but is highly soluble in [[Alcohol (chemistry)|alcohol]]s, other organic solvents, and in strongly [[alkali]]ne aqueous solutions due to [[deprotonation]] of the [[phenol]].

== Chemical synthesis ==
Thymol is produced by the [[alkylation]] of [[M-Cresol|''m''-cresol]] and [[propene]].<ref>{{cite book|last1=Stroh|first1=R.|last2=Sydel|first2=R.|last3=Hahn|first3=W.|editor1-last=Foerst|editor1-first=Wilhelm|title=Newer Methods of Preparative Organic Chemistry, Volume 2|date=December 2012|publisher=Academic Press|location=New York|isbn=9780323150422|page=344|edition= 1st|url=https://books.google.com/books?id=LG2J6i1sUAMC&pg=PA344}}</ref><ref>{{Ullmann |doi=10.1002/14356007.a19_313|title=Phenol Derivatives |year=2000 |last1=Fiege |first1=Helmut |last2=Voges |first2=Heinz-Werner |last3=Hamamoto |first3=Toshikazu |last4=Umemura |first4=Sumio |last5=Iwata |first5=Tadao |last6=Miki |first6=Hisaya |last7=Fujita |first7=Yasuhiro |last8=Buysch |first8=Hans-Josef |last9=Garbe |first9=Dorothea |last10=Paulus |first10=Wilfried |isbn=3527306730 }}</ref>
{{chem2|CH3C6H4OH + CH2CHCH3  -> ((CH3)2CH)CH3C6H3OH}}

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. Its dissociation constant ([[pKa|p''K''<sub>a</sub>]]) is {{val|10.59|0.10}}.<ref>CAS Registry: Data obtained from SciFinder{{full citation needed|date=August 2017}}</ref> Thymol absorbs maximum [[ultraviolet|UV]] radiation at 274&nbsp;nm.<ref>{{cite journal | last1 = Norwitz | first1 = G. | last2 = Nataro | first2 = N. | last3 = Keliher | first3 = P. N. | year = 1986 | title = Study of the Steam Distillation of Phenolic Compounds Using Ultraviolent Spectrometry | journal = Anal. Chem. | volume = 58 | issue = 639–640| page = 641 | doi = 10.1021/ac00294a034 }}</ref>

==History==
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 [[poultice]]s of the plants for skin [[infection]]s and minor [[wound]]s. A [[tisane]] made from them was also used to treat mouth and throat [[infection]]s caused by dental [[caries]] and [[gingivitis]].<ref>{{cite book|last=Tilford |first=Gregory L. |date=1997 |title=Edible and Medicinal Plants of the West |location=Missoula, MT |publisher=Mountain Press Publishing |isbn=978-0-87842-359-0}}</ref>

Thymol was first isolated by German chemist [[Caspar Neumann (chemist)|Caspar Neumann]] in 1719.<ref>{{cite journal|first=Carolo |last=Neuman |date=1724 |title=De Camphora |journal=Philosophical Transactions of the Royal Society of London |volume=33 |issue=389 |pages=321–332 |url=http://rstl.royalsocietypublishing.org/content/33/381-391/321.full.pdf+html |doi=10.1098/rstl.1724.0061|doi-access=free |url-access=subscription }} On page 324, Neumann mentions that in 1719 he distilled some essential oils from various herbs. On page 326, he mentions that during these experiments, he obtained a crystalline substance from thyme oil, which he called "''Camphora Thymi''" ([[camphor]] of thyme). (Neumann gave the name "camphor" not only to the specific substance that today is called camphor but to any crystalline substance that precipitated from a volatile, fragrant oil from some plant.)</ref> In 1853, French chemist Alexandre Lallemand<ref>Marie-Étienne-Alexandre Lallemand (December 25, 1816 - March 16, 1886)</ref> (1816-1886) named thymol and determined its empirical formula.<ref>{{cite journal|first=A. |last=Lallemand |date=1853 |url=http://gallica.bnf.fr/ark:/12148/bpt6k29948/f502.image.langEN |title=Sur la composition de l'huile essentielle de thym |trans-title=On the composition of the essential oil of thyme |language=fr |journal=Comptes Rendus |volume=37 |pages=498–500}}</ref> Possible [[antiseptic]] properties of thymol were discovered in 1875,<ref>{{Cite book |last=Oettingen |first=Wolfgang Felix Von |url=https://books.google.com/books?id=reaUWvD-bhYC&pg=PA78 |title=Phenol and Its Derivatives: The Relation Between Their Chemical Constitution and Their Effect on the Organism |date=1949 |publisher=U.S. Government Printing Office |isbn= |language=en}}</ref> and it was first synthesized by Swedish chemist Oskar Widman (1852-1930) in 1882.<ref>{{cite journal|first=Oskar |last=Widmann |date=1882 |url=http://gallica.bnf.fr/ark:/12148/bpt6k90694n/f169.image.langEN |title=Ueber eine Synthese von Thymol aus Cuminol |trans-title=On a synthesis of thymol from cuminol |language=de |journal=Berichte der Deutschen Chemischen Gesellschaft zu Berlin |volume=15 |pages=166–172 |doi=10.1002/cber.18820150139}}</ref>

==Extraction==

The conventional method of [[extract]]ing is [[Hydrodistillation|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.<ref>{{Cite journal |last1=Lucchesi |first1=Marie E |last2=Chemat |first2=Farid |last3=Smadja |first3=Jacqueline |date=2004-07-23 |title=Solvent-free microwave extraction of essential oil from aromatic herbs: comparison with conventional hydro-distillation |url=https://www.sciencedirect.com/science/article/pii/S0021967304008672 |journal=Journal of Chromatography A |volume=1043 |issue=2 |pages=323–327 |doi=10.1016/j.chroma.2004.05.083 |pmid=15330107 |issn=0021-9673|url-access=subscription }}</ref> 

[[File:Thymol biosynthesis.svg|center|thumb|500px|Predicted biosynthesis of thymol in thyme and oregano. Reconstruction of figure 4 in Krause et. al. (2021).<ref name="r505">{{cite journal | last=Krause | first=Sandra T. | last2=Liao | first2=Pan | last3=Crocoll | first3=Christoph | last4=Boachon | first4=Benoît | last5=Förster | first5=Christiane | last6=Leidecker | first6=Franziska | last7=Wiese | first7=Natalie | last8=Zhao | first8=Dongyan | last9=Wood | first9=Joshua C. | last10=Buell | first10=C. Robin | last11=Gershenzon | first11=Jonathan | last12=Dudareva | first12=Natalia | last13=Degenhardt | first13=Jörg | title=The biosynthesis of thymol, carvacrol, and thymohydroquinone in Lamiaceae proceeds via cytochrome P450s and a short-chain dehydrogenase | journal=Proceedings of the National Academy of Sciences | volume=118 | issue=52 | date=2021-12-28 | issn=0027-8424 | pmid=34930840 | pmc=8719858 | doi=10.1073/pnas.2110092118 | page=}}</ref>]]

==Uses==
During the 1910s, thymol was used for [[hookworm infection]] in the United States.<ref>{{cite book|last=Ferrell|first=John Atkinson|title=The Rural School and Hookworm Disease|url=https://books.google.com/books?id=omYAAAAAYAAJ|series=US Bureau of Education Bulletin|volume=20, Whole No. 593|year=1914|publisher=U.S. Government Printing Office|location=Washington, DC}}</ref><ref name="Rosenau1913">{{cite book|surname=Milton|given=Joseph Rosenau|title=Preventive Medicine and Hygiene|url=https://books.google.com/books?id=mVfQAAAAMAAJ&pg=PA119|year=1913|publisher=D. Appleton|page=119}}</ref> People of the Middle East continue to use [[za'atar]], a delicacy made with large amounts of thyme, to reduce and eliminate internal parasites.<ref>{{Cite news|last1=Inskeep|first1=Steve|last2=Godoy|first2=Maria|date=2013-06-11|title=Za'atar: A Spice Mix With Biblical Roots And Brain Food Reputation|language=en|work=NPR|url=https://www.npr.org/sections/thesalt/2013/06/11/190672515/zaatar-a-spice-mix-with-biblical-roots-and-brain-food-reputation|access-date=2022-02-24}}</ref>  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.<ref>{{cite journal | last1 = Filoche | first1 = S. K. | last2 = Soma | first2 = K. | last3 = Sissons | first3 = C. H. | year = 2005 | title = Antimicrobial effects of essential oils in combination with chlorhexidine digluconate | journal = Oral Microbiol. Immunol. | volume = 20 | issue = 4| pages = 221–225 | doi = 10.1111/j.1399-302X.2005.00216.x | pmid = 15943766 }}</ref> 

Thymol is a fragrance ingredient in some [[cosmetics]].<ref name=pubchem/> Thymol has been used to successfully control [[varroa mite]]s and prevent fermentation and the growth of [[Mold (fungus)|mold]] in [[bees|bee colonies]].<ref name=bees>{{cite news|last=Ward |first=Mark |date=2006-03-08 |url=http://news.bbc.co.uk/2/hi/science/nature/4780034.stm |title=Almond farmers seek healthy bees |website=BBC News |publisher=BBC}}</ref> Thymol is also used as a rapidly degrading, non-persisting [[pesticide]],<ref name=pubchem/><ref name="J. Coats 2008" /> such as insecticides and fungicides which are leveraged in plant care products. Thymol can also be used as a medical disinfectant and general purpose [[disinfectant]].<ref>{{cite web|url=http://archive.epa.gov/pesticides/reregistration/web/pdf/3143fact.pdf|title=Thymol|publisher=US Environmental Protection Agency|date=September 1993}}</ref> Thymol is also used in the production of [[menthol]] through the hydrogenation of the aromatic ring.<ref>{{Cite web |date=2023-10-06 |title=Menthol {{!}} Definition, Structure, & Uses {{!}} Britannica |url=https://www.britannica.com/science/menthol |access-date=2023-10-30 |website=www.britannica.com |language=en}}</ref>

==List of plants that contain thymol==
{{div col|colwidth=10em}}
* ''[[Illicium verum]]''
* ''[[Euphrasia rostkoviana]]''<ref>{{cite journal | pmid = 26000025 | doi=10.1155/2015/734101 | volume=2015 | title=Composition and Antimicrobial Activity of ''Euphrasia rostkoviana'' Hayne Essential Oil | pmc=4427012 | journal=Evid Based Complement Alternat Med | pages=1–5 | last1 = Novy | first1 = P. | last2 = Davidova | first2 = H. | last3 = Serrano Rojero | first3 = C. S. | last4 = Rondevaldova | first4 = J. | last5 = Pulkrabek | first5 = J. | last6 = Kokoska | first6 = L.| year=2015 | doi-access=free }}</ref>
* ''[[Lagoecia cuminoides]]''<ref>{{cite journal |doi=10.1080/10412905.1994.9698448 |title=Composition of the Essential Oil of ''Lagoecia cuminoides'' L. from Turkey |year=1994 |last1=Baser |first1=K. H.C. |last2=Tümen |first2=G. |journal=Journal of Essential Oil Research |volume=6 |issue=5 |pages=545–546 }}</ref>
* ''[[Monarda didyma]]''<ref>{{cite journal|author1=Donata Ricci|author2=Francesco Epifano|author3=Daniele Fraternale|editor=Olga Tzakou|title=The Essential Oil of Monarda didyma L. (Lamiaceae) Exerts Phytotoxic Activity In Vitro against Various Weed Seeds|journal=Molecules (Basel, Switzerland)|publisher=[[Molecules (journal)|Molecules]]|date=February 2017|volume=22|issue=2|pages=222|pmc=6155892|pmid=28157176|doi=10.3390/molecules22020222|doi-access=free}}</ref>
* ''[[Monarda fistulosa]]''<ref>{{cite journal|first1=V. A. |last1=Zamureenko |first2=N. A. |last2=Klyuev |first3=B. V. |last3=Bocharov |first4=V. S. |last4=Kabanov |first5=A. M. |last5=Zakharov |title=An investigation of the component composition of the essential oil of ''Monarda fistulosa'' |journal=Chemistry of Natural Compounds |volume=25 |issue=5 |date=1989 |pages=549–551 |doi=10.1007/BF00598073 |s2cid=24267822 |issn=1573-8388}}</ref>
* ''[[Mosla|Mosla chinensis]]'' 
* [[Ocimum gratissimum|''Ocimum gratissimum'' L]].<ref>{{Cite journal |last1=Escobar |first1=Angélica |last2=Pérez |first2=Miriam |last3=Romanelli |first3=Gustavo |last4=Blustein |first4=Guillermo |date=2020-12-01 |title=Thymol bioactivity: A review focusing on practical applications |journal=Arabian Journal of Chemistry |volume=13 |issue=12 |pages=9243–9269 |doi=10.1016/j.arabjc.2020.11.009 |issn=1878-5352|doi-access=free |hdl=11336/139451 |hdl-access=free }}</ref>
* ''[[Origanum compactum]]''<ref name=ccaa />
* ''[[Origanum dictamnus]]''<ref name=lict>{{cite journal
| last1 = Liolios
| first1 = C. C.
| title = Liposomal incorporation of carvacrol and thymol isolated from the essential oil of ''Origanum dictamnus'' L. and in vitro antimicrobial activity
| journal = Food Chemistry
| volume = 112
| issue = 1
| pages = 77–83
| year = 2009
| doi = 10.1016/j.foodchem.2008.05.060
| last2 = Gortzi
| first2 = O.
| last3 = Lalas
| first3 = S.
| last4 = Tsaknis
| first4 = J.
| last5 = Chinou
| first5 = I.}}</ref>
* ''[[Origanum onites]]''<ref name=ihte>{{cite journal
| last1 = Ozkan
| first1 = Gulcan
| title = The influence of harvest time on essential oil composition, phenolic constituents and antioxidant properties of Turkish oregano (''Origanum onites'' L.)
| journal = Journal of the Science of Food and Agriculture
| volume = 90
| issue = 2
| pages = 205–209
| year = 2009
| doi = 10.1002/jsfa.3788
| pmid = 20355032
| last2 = Baydar
| first2 = H.
| last3 = Erbas
| first3 = S.}}</ref><ref name=caae>{{cite journal
| last1 = Lagouri
| first1 = Vasiliki
| title = Composition and antioxidant activity of essential oils from Oregano plants grown wild in Greece
| journal = Zeitschrift für Lebensmittel-Untersuchung und -Forschung A
| volume = 197
| issue = 1
| pages = 1431–4630
| year = 1993
| doi = 10.1007/BF01202694
| last2 = Blekas
| first2 = George
| last3 = Tsimidou
| first3 = Maria
| last4 = Kokkini
| first4 = Stella
| last5 = Boskou
| first5 = Dimitrios| s2cid = 81307357
}}</ref>
* ''[[Origanum syriacum]]
* ''[[Origanum vulgare]]''<ref name=teeo>{{cite journal
| last1 = Kanias
| first1 = G. D.
| title = Trace elements and essential oil composition in chemotypes of the aromatic plant ''Origanum vulgare''
| journal = Journal of Radioanalytical and Nuclear Chemistry
| volume = 227
| issue = 1–2
| pages = 23–31
| year = 1998
| doi = 10.1007/BF02386426
| last2 = Souleles
| first2 = C.
| last3 = Loukis
| first3 = A.
| last4 = Philotheou-Panou
| first4 = E.| s2cid = 94582250
}}</ref><ref name=coeo>{{cite journal
| last1 = Figiel
| first1 = Adam
| title = Composition of oregano essential oil (''Origanum vulgare'') as affected by drying method
| journal = Journal of Food Engineering
| volume = 98
| issue = 2
| pages = 240–247
| year = 2010
| doi = 10.1016/j.jfoodeng.2010.01.002
| last2 = Szumny
| first2 = Antoni
| last3 = Gutiérrez Ortíz
| first3 = Antonio
| last4 = Carbonell Barrachina
| first4 = Ángel A.}}</ref>
* ''[[Satureja hortensis]]''
* ''[[Satureja thymbra]]''
* ''[[Thymus glandulosus]]''<ref name=ccaa>{{cite journal
| last1 = Bouchra
| first1 = Chebli
| title = Chemical composition and antifungal activity of essential oils of seven Moroccan Labiatae against ''Botrytis cinerea'' Pers: Fr
| journal = Journal of Ethnopharmacology
| volume = 89
| issue = 1
| pages = 165–169
| year = 2003
| doi = 10.1016/S0378-8741(03)00275-7
| pmid = 14522450
| last2 = Achouri
| first2 = Mohamed
| last3 = Idrissi Hassani
| first3 = L. M.
| last4 = Hmamouchi
| first4 = Mohamed}}</ref>
* ''[[Thymus hyemalis]]''<ref name=apth />
* ''[[Thymus serpyllum]]''
* ''[[Thymus praecox]]''
* ''[[Thymus vulgaris]]''<ref name=apth>{{cite journal
| last1 = Goodner
| first1 = K.L.
| title = Aromatic profiles of ''Thymus hyemalis'' and Spanish ''T. vulgaris'' essential oils by GC–MS/GC–O
| journal = Industrial Crops and Products
| volume = 24
| issue = 3
| pages = 264–268
| year = 2006
| doi = 10.1016/j.indcrop.2006.06.006
| last2 = Mahattanatawee
| first2 = K.
| last3 = Plotto
| first3 = A.
| last4 = Sotomayor
| first4 = J.
| last5 = Jordán
| first5 = M.}}</ref><ref name=ivcb>{{cite journal
| last1 = Lee
| first1 = Seung-Joo
| title = Identification of volatile components in basil (''Ocimum basilicum'' L.) and thyme leaves (''Thymus vulgaris'' L.) and their antioxidant properties
| journal = Food Chemistry
| volume = 91
| issue = 1
| pages = 131–137
| year = 2005
| doi = 10.1016/j.foodchem.2004.05.056
| last2 = Umano
| first2 = Katumi
| last3 = Shibamoto
| first3 = Takayuki
| last4 = Lee
| first4 = Kwang-Geun}}</ref>
* ''[[Thymus zygis]]''<ref name=scet>{{cite journal
| last1 = Moldão Martins
| first1 = M.
| title = Supercritical CO<sub>2</sub> extraction of ''Thymus zygis'' L. subsp. ''sylvestris'' aroma
| journal = The Journal of Supercritical Fluids
| volume = 18
| issue = 1
| pages = 25–34
| year = 2000
| doi = 10.1016/S0896-8446(00)00047-4
| last2 = Palavra
| first2 = A.
| last3 = Beirão da Costa
| first3 = M. L.
| last4 = Bernardo Gil
| first4 = M. G.}}</ref>
* ''[[Trachyspermum ammi]]''
{{div col end}}

==Toxicology and environmental impacts==
[[File:Thymolum by Danny S. - 001.JPG|thumb|200px|Thymol powder]]
In 2009, the [[United States Environmental Protection Agency|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".<ref>{{Federal Register|74|12613}}</ref>

===Environmental breakdown and use as a pesticide===
Studies have shown that hydrocarbon [[monoterpenes]] and thymol in particular degrade rapidly (DT<sub>50</sub> 16 days in water, 5 days in soil<ref name="J. Coats 2008">{{cite journal|first1=D. |last1=Hu |first2=J. |last2=Coats |title=Evaluation of the environmental fate of thymol and phenethyl propionate in the laboratory |journal=Pest Manag. Sci. |volume=64 |issue=7 |pages=775–779 |date=2008 |doi=10.1002/ps.1555|pmid=18381775 }}</ref>) in the environment and are, thus, low risks because of rapid dissipation and low bound residues,<ref name="J. Coats 2008"/> 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 [[polysaccharide]]s which would be biodegradable and biocompatible.<ref>{{Cite journal |last1=Campos |first1=Estefânia V. R. |last2=Proença |first2=Patrícia L. F. |last3=Oliveira |first3=Jhones L. |last4=Bakshi |first4=Mansi |last5=Abhilash |first5=P. C. |last6=Fraceto |first6=Leonardo F. |date=2019-10-01 |title=Use of botanical insecticides for sustainable agriculture: Future perspectives |url=https://www.sciencedirect.com/science/article/pii/S1470160X18302917 |journal=Ecological Indicators |volume=105 |pages=483–495 |doi=10.1016/j.ecolind.2018.04.038 |issn=1470-160X|hdl=11449/179822 |s2cid=89798604 |hdl-access=free }}</ref>

==Compendial status==
* [[British Pharmacopoeia]]<ref name=ib29>{{cite web
 |last        = The British Pharmacopoeia Secretariat
 |title       = Index, BP 2009
 |year        = 2009
 |url         = http://www.pharmacopoeia.co.uk/pdf/2009_index.pdf
 |access-date  = 2009-07-05
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20090411071437/http://www.pharmacopoeia.co.uk/pdf/2009_index.pdf
 |archive-date = 11 April 2009}}</ref>
* [[Japanese Pharmacopoeia]]<ref name=jp15>{{cite web| title =Japanese Pharmacopoeia| url =http://jpdb.nihs.go.jp/jp15e/JP15.pdf| access-date =2010-04-21| url-status =dead| archive-url =https://web.archive.org/web/20110722105441/http://jpdb.nihs.go.jp/jp15e/JP15.pdf| archive-date =22 July 2011}}</ref>

==See also==
*[[Thymoquinone]]
*''[[Nigella sativa]]''
*[[Bromothymol]]

==Notes and references==
{{reflist|30em}}

==External links==
{{commons category-inline}}

{{GABAAR PAMs}}
{{Transient receptor potential channel modulators}}
{{Terpenoids}}

[[Category:Fungicides]]
[[Category:Disinfectants]]
[[Category:Flavors]]
[[Category:Monoterpenes]]
[[Category:Alkylphenols]]
[[Category:GABAA receptor positive allosteric modulators]]
[[Category:Isopropyl compounds]]