Myrcene
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| Preferred IUPAC name
7-Methyl-3-methylideneocta-1,6-diene | |
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| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.004.203 |
| KEGG | |
PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| C10H16 | |
| Molar mass | 136.238 g·mol−1 |
| Density | 0.794 g/cm3 |
| Melting point | < −10 °C (14 °F; 263 K) |
| Boiling point | 166 to 168 °C (331 to 334 °F; 439 to 441 K)[2] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Myrcene, or β-myrcene, is a monoterpene. A colorless oil, it occurs widely in essential oils. It can be obtained from Myrcia, from which it gets its name. It is an intermediate in the production of several fragrances.[3] A less-common isomeric form, having one of the three alkene units in a different position, is α-myrcene.
Production
[edit]
Myrcene is often produced commercially by the pyrolysis (400 °C) of β-pinene, which is obtained from turpentine.[3] It is rarely obtained directly from plants.[4]
Plants biosynthesize myrcene via geranyl pyrophosphate (GPP), which isomerizes into linalyl pyrophosphate. An elimination reaction, releasing the pyrophosphate (OPP) and a proton, completes the conversion.[5]
Occurrence
[edit]It could in principle be extracted from any number of plants, such as verbena or wild thyme, the leaves of which contain up to 40% by weight of myrcene.[4] Many other plants contain substantial amounts of myrcene.[3] Some of these include cannabis,[6] hops (Humulus lupulus), Houttuynia, lemon grass, mango, Myrcia, West Indian bay tree, and cardamom.[7]
Myrcene is found in the South African Adenandra villosa (50%)[8] and Brazilian Schinus molle (40%).[9] It also occurs in Myrcia cuprea petitgrain (up to 48%),[10] bay leaf, and juniper berry.[3][11]
Use in fragrance and flavor industries
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Although it has a pleasant odor, myrcene is rarely used directly in the perfumery industry.[3] Instead, myrcene is a versatile precursor to many useful fragrances, such as menthol, citral, citronellol, citronellal, geraniol, nerol, and linalool. Several of these result from myrcene's reactions with hydrogen chloride to give geranyl chloride, neryl chloride, linalyl chloride, and myrcenyl chloride, all of which can be hydrolyzed to the corresponding alcohols.[4]
Both myrcene and myrcenol undergo Diels–Alder reactions with several dienophiles, such as acrolein. One of the resulting cyclohexene derivatives is Lyral.[2] Another fragrance compound made from myrcene is Ambramone.[12]
Myrcene also contributes a peppery, balsamic aroma in beer.[13][14]
Polymerization
[edit]Like other conjugated dienes, including other terpenes, myrcene is prone to polymerization.[15] Samples are stabilized by the addition of alkylphenols or tocopherol. Some of these polymers are useful, such as a phenol-myrcene copolymer and resins derived from maleic anhydride.[4]
Health and safety
[edit]Myrcene, like most terpenes, has very low acute toxicity, estimated to be >5g/kg (oral for rats, rabbits).[4]
As of October 2018, the U.S. FDA withdrew authorization for the use of myrcene as a synthetic flavoring substance in food, without regard to its continuing stance that this substance does not pose a risk to public health under the conditions of its intended use.[16]
The International Agency for Research on Cancer (IARC) determined that β-myrcene is "possibly carcinogenic to humans" (Group 2B) in 2019.[17]
See also
[edit]References
[edit]- ↑ Merck Index, 11th Edition, 6243
- 1 2 Fahlbusch, K.-G.; Hammerschmidt, F.-J.; Panten, J.; Pickenhagen, W.; Schatkowski, D.; Bauer, K.; Garbe, D.; Surburg, H. (2002). "Flavors and Fragrances". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a11_141. ISBN 3-527-30673-0.
- 1 2 3 4 5 Behr, A.; Johnen, L. (2009). "Myrcene as a Natural Base Chemical in Sustainable Chemistry: A Critical Review". ChemSusChem. 2 (12): 1072–1095. Bibcode:2009ChSCh...2.1072B. doi:10.1002/cssc.200900186. PMID 20013989.
- 1 2 3 4 5 M. Eggersdorfer (2005). "Terpenes". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a26_205. ISBN 3-527-30673-0.
- ↑ Dewick, Paul M. (2002). Medicinal Natural Products: A Biosynthetic Approach. New York: John Wiley and Sons, Ltd. p. 174. ISBN 0-471-49641-3.
- ↑ Booth, Judith K.; Page, Jonathan E.; Bohlmann, Jörg (29 March 2017). Hamberger, Björn (ed.). "Terpene synthases from Cannabis sativa". PLOS One. 12 (3) e0173911. Bibcode:2017PLoSO..1273911B. doi:10.1371/journal.pone.0173911. ISSN 1932-6203. PMC 5371325. PMID 28355238.
- ↑ Marongiu, B; Piras, A; Porcedda, S (2004). "Comparative analysis of the oil and supercritical CO2 extract of Elettaria cardamomum (L.) Maton". Journal of Agricultural and Food Chemistry. 52 (20): 6278–82. doi:10.1021/jf034819i. PMID 15453700.
- ↑ Baser, K. H. C.; Demirci, B.; Ozek, T.; Viljoen, A. M.; Victor, J. E. (2006). "Composition of the essential oils of two Adenandra species from South Africa". Journal of Essential Oil Research.
- ↑ Dannenberg, Guilherme da Silva; Funck, Graciele Daiana; Silva, Wladimir Padilha da; Fiorentini, Ângela Maria (2019). "Essential oil from pink pepper (Schinus terebinthifolius Raddi): Chemical composition, antibacterial activity and mechanism of action". Food Control. 95: 115–120. doi:10.1016/j.foodcont.2018.07.034. S2CID 92548775.
- ↑ Zoghbi, M das Graças B.; Andrade, Eloisa Helena A.; Da Silva, Milton Helio L.; Carreira, L. M. M.; Maia, J. G. S. (2003). "Essential oils from three Myrcia species". Flavour and Fragrance Journal. 18 (5): 421–424. doi:10.1002/ffj.1242.
- ↑ Chyau, C.-C.; Mau, J.-L.; Wu, C.-M. (1996). "Characteristics of the Steam-Distilled Oil and Carbon Dioxide Extract of Zanthoxylum simulans Fruits". Journal of Agricultural and Food Chemistry. 44 (4): 1096–1099. doi:10.1021/jf950577d.
- ↑ Armanino, N., Charpentier, J., Flachsmann, F., Goeke, A., Liniger, M., Kraft, P. (14 September 2020). "What's Hot, What's Not: The Trends of the Past 20 Years in the Chemistry of Odorants". Angewandte Chemie International Edition. 59 (38): 16310–16344. doi:10.1002/anie.202005719. PMID 32453472.
- ↑ Inui, T; Tsuchiya, F; Ishimaru, M; Oka, K; Komura, H (2013). "Different beers with different hops. Relevant compounds for their aroma characteristics". Journal of Agricultural and Food Chemistry. 61 (20): 4758–64. doi:10.1021/jf3053737. PMID 23627300.
- ↑ Vázquez Araújo, L.; Rodríguez Solana, R; Cortés Diéguez, S. M.; Domínguez, J. M. (2013). "Use of hydrodistillation and headspace solid-phase microextraction to characterize the volatile composition of different hop cultivars". Journal of the Science of Food and Agriculture. 93 (10): 2568–74. Bibcode:2013JSFA...93.2568V. doi:10.1002/jsfa.6078. PMID 23483584.
- ↑ Wahlen, Christian; Frey, Holger (2021). "Anionic Polymerization of Terpene Monomers: New Options for Bio-Based Thermoplastic Elastomers". Macromolecules. 54 (16): 7323–7336. doi:10.1021/acs.macromol.1c00770.
- ↑ 83 FR 50490
- ↑ IARC Working Group on the Evaluation of Carcinogenic Risks to Humans (2019). "Some chemicals that cause tumours of the urinary tract in rodents". International Agency for Research on Cancer. PMID 31550098. Retrieved 20 April 2026.