Fig1. Mevalonate and Non-Mevalonate pathway. two pathways from different organisms


Due to these molecules possessing fragrance qualities, they are used in industry for the production of perfumes, cosmetics, household products, etc.

Our project focuses on the synthesis of selected terpene fragrant compounds: zingiberene, R-linalool and limonene, by expressing each enzyme in E.coli.

Limonene synthase:

Limonene is a scented cyclic terpene, from the hydrocarbon family. The major fragrance it is associated with is lemons, citrus fruits have large amounts of the compound and it is known to give off the scent associated with the fruits. Usually limonene is harvested from fruits using steam distillation or centrifugal separation, steam distillation yields around 1%, this is far greater than other distillation techniques which can yield as low as 0.1%.
Limonene is a very common ingredient in cosmetic products, often found in shampoos, lotions, perfumes and other everyday items. The demand for it is huge; as the yield is so small farming products is very wasteful.

Zingiberene Synthase:

Zingiberene synthase is an enzyme found in ginger rhizomes (Zingiber officinale). It converts farnesyl diphosphate into zingiberene and diphosphate in a single enzymatic reaction. Zingiberene (C15H24) is classified as a sesquiterpene - a terpene that is characterized by the presence of 15 carbon atoms. It is a consitutient of the ginger oil that is extracted from rhizomes (roots) and is responsible for the pleasant ginger aroma of the plant.

Use of zingiberene:

Zingiberene contributes to the scents in many commercial perfumes. This is achieved via steam distillation of the ginger rhizomes. These contain approximately 1-3% of the essential fragrant oil, where the major component is zingiberene (34%).

Additionally it also possesses medicinal properties which can be further researched such as anti – inflammatory and anti-cancer.

R-linalool Synthase:

R-linalool is classified as a terpenoid that is found in the essential oil of the Lavandula family that contributes to the lavender scent. It is synthesized by the enzyme R-linalool synthase using Geranyl diphosphate and water as substrates, producing R-linalool and Diphosphate as products (fig2). Lavender is a scent that is employed by the fragrance industry: e.g. soaps, skin lotions, cleaning products, perfumes and other products.

Production:

There are different methods to manufacture R-Linalool.
Fractional distilliation of the essential oil from plants such as Bois de rose (rosewood), shiu or coriander.
The major sources of R- Linalool are Brazilian rosewood, Chinese and Taiwanese Ho leaf. In for example Freesia, the R-linalool exists as the R-(-) enantiomer only. The chemical synthesis of R-Linalool involves reactants: acetylene and acetone or isoprene hydrochloride.

In the year 2000, approximately 12,000 tonnes of Linalool was produced out of which more than half was synthesized chemically.


Other properties of R-Linalool:

Many researchers have studied the physiological effects of these odours such as sleep, aggressiveness, muscle tension, etc. Experiments conducted by Hardy et al suggested that R-linalool has a significant sedating effect. This is because it is considered that terpenes have the ability to potentiate the GABAA receptor activity in particular regions of the brain.

References:

Rachel Davidovich-Rikanati, Efraim Lewinsohn, Einat Bar, Yoko Iijima, Eran Pichersky and Yaron Sitrit. (2008). Overexpression of the lemon basil α-zingiberene synthase gene increases both mono- and sesquiterpene contents in tomato fruit. The Plant Journal. 56 (2), 228-238.

Kunkum Rani. (1999). Cyclisation of farnesyl pyrophosphate into sesquiterpenoids in ginger rhizomes (Zingiber officinale). Fitoterapia. 70 (6), 568-574.

George F antonious. (2008). The presence of zingiberene and Curcumene in wild tomato leaves. In: Victor R. Preedy and Ronald R Watson Tomatoes and tomato products. Enfield USA: Science Publishers. 193-215.

Jeffrey B Harbourne. (2001). Essential Oils. In: Chemical Dictionary of economic plants. Chichester Sussex: John Wiley & Sons Ltd. 78.

Hyun Jo Koo, David R Gang. (2012). Suites of Terpene Synthases Explain Differential Terpenoid Production in Ginger and Turmeric Tissues. Available: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0051481. Last accessed 17/10/2014.

Linalool

Landmann C. (2007). Cloning and functional characterization of three terpene synthases from lavender (Lavandula angustifolia).. Arch Biochem Biophys. 1 (1), 417-429.
Nam-Sun Kim. (2002). Comparison of different extraction methods for the analysis of fragrances from Lavandula species by gas chromatography–mass spectrometry. Science Direct. 982 (1), 31-47.

Eva Heuberger. (2001). Effects of Chiral Fragrances on Human Autonomic Nervous System Parameters and Self-evaluation. Oxford Journals. 26 (3), 281-292.
Maria Lis-Balchin. (2004). Lavender oil and its therapeutic properties. In: Maria Lis-Balchin Lavender: The Genus Lavendula. London: Taylor & Francis. 127-.

N/A. (2004). Linalool. Available: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=6549. Last accessed 17/10/2014.

TOXNET. (2009). Linalool. Available: http://toxnet.nlm.nih.gov/cgi-bin/sis/search2/r?dbs+hsdb:@term+@rn+@rel+78-70-6. Last accessed 17/10/2014.

Yoko Iijima. (2004). The Biochemical and Molecular Basis for the Divergent Patterns in the Biosynthesis of Terpenes and Phenylpropenes in the Peltate Glands of Three Cultivars of Basil1. Available: http://www.plantphysiol.org/content/136/3/3724.long. Last accessed 17/10/2014.

Tony Burfield. (2004). Linalool-Containing Essential Oils: New Safe Use Proposal. Available: http://www.users.globalnet.co.uk/~nodice/new/magazine/linalool/linaloo.htm. Last accessed 17/10/2014.

N/A. (n/a). Essential Oils. Available: http://www.bojensen.net/EssentialOilsEng/EssentialOils11A/EssentialOils11A.htm. Last accessed 17/10/2014.