Terpinene Explained

The terpinenes are a group of isomeric hydrocarbons that are classified as monoterpenes. They each have the same molecular formula and carbon framework, but they differ in the position of carbon-carbon double bonds. α-Terpinene has been isolated from cardamom and marjoram oils, and from other natural sources. β-Terpinene has no known natural source but has been prepared from sabinene. γ-Terpinene and δ-terpinene (also known as terpinolene) have been isolated from a variety of plant sources. They are all colorless liquids with a turpentine-like odor.[1]

Production and uses

α-Terpinene is produced industrially by acid-catalyzed rearrangement of α-pinene. It has perfume and flavoring properties but is mainly used to confer pleasant odor to industrial fluids. Hydrogenation gives the saturated derivative p-menthane.[1]

Biosynthesis of α-terpinene

The biosynthesis of α-terpinene and other terpenoids starts with the isomerization of geranyl pyrophosphate to linalyl pyrophosphate (LPP). LPP then forms a resonance-stabilized cation by loss of the pyrophosphate group. Cyclization is then completed thanks to this more favorable stereochemistry of the LPP cation, yielding a terpinyl cation.[2] Finally, a 1,2-hydride shift via a Wagner-Meerwein rearrangement produces the terpinen-4-yl cation. It is the loss of a hydrogen from this cation that generates α-terpinene.

Plants that produce terpinene

Notes and References

  1. Encyclopedia: M. Eggersdorfer . Terpenes. Ullmann's Encyclopedia of Industrial Chemistry. 2005. Wiley-VCH. Weinheim. 10.1002/14356007.a26_205. 3-527-30673-0.
  2. 10.1021/acs.chemrev.7b00287. Structural and Chemical Biology of Terpenoid Cyclases . 2017 . Christianson . David W. . Chemical Reviews . 117 . 17 . 11570–11648 . 28841019 . 5599884 .
  3. Li . Rong . Zi-Tao Jiang . Chemical composition of the essential oil of Cuminum cyminum L. from China . Flavour and Fragrance Journal . 19 . 4 . 311–313 . 2004 . 10.1002/ffj.1302 .
  4. Wang . Lu . Ultrasonic nebulization extraction coupled with headspace single drop microextraction and gas chromatography–mass spectrometry for analysis of the essential oil in Cuminum cyminum L. . Analytica Chimica Acta . 647 . 1 . 72–77 . 2009 . 10.1016/j.aca.2009.05.030 . 19576388 . Wang . Z . Zhang . H . Li . X . Zhang . H . 2009AcAC..647...72W . etal.
  5. Iacobellis . Nicola S. . Antibacterial Activity of Cuminum cyminum L. and Carum carvi L. Essential Oils . Journal of Agricultural and Food Chemistry . 53 . 1 . 57–61 . 2005 . 10.1021/jf0487351 . 15631509 . Lo Cantore . P . Capasso . F . Senatore . F . etal.
  6. Hillig. Karl W. October 2004. A chemotaxonomic analysis of terpenoid variation in Cannabis. Biochemical Systematics and Ecology. 32. 10. 875–891. 10.1016/j.bse.2004.04.004. 2004BioSE..32..875H . 0305-1978.
  7. Shahwar. Muhammad Khuram. El-Ghorab. Ahmed Hassan. Anjum. Faqir Muhammad. Butt. Masood Sadiq. Hussain. Shahzad. Nadeem. Muhammad. 2012-07-01. Characterization of Coriander (Coriandrum sativum L.) Seeds and Leaves: Volatile and Non Volatile Extracts. International Journal of Food Properties. 15. 4. 736–747. 10.1080/10942912.2010.500068. 1094-2912. free.

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