Monoterpenes linalool

Foss S, J Harder (1998) Thauera linaloolentis sp. nov. and Thauera terpenica sp. nov., isolated on oxygen-containing monoterpenes (linalool, menthol, and eucalyptol) and nitrate. System Appl Microbiol 21 365-373. 

It is well established that the iridoids are derived from two units of mevalonic acid (97), which itself is derived from acetyl-CoA. Mevalonate is also known to be a metabolic product of leucine (172), and the latter is a precursor of the monoterpene linalool (173). Wigfield and Wen (174) pursued the incorporation of leucine into the monoterpene unit in both vindoline (3) and catharanthine (4), where levels of 0.07 and 0.02%, respectively, were found, irrespective of the amount of precursor fed. This was important because, although initial results were obtained with [2- C] leucine, the specificity of incorporation was determined with 2- C-la-beled precursor. Two carbons in vindoline (3), C-8 and C-24, were en-... 

The odorless polyols appear to be derived from four "parent" monoterpenes - linalool, citronellol, nerol and geraniol by hydration and oxidation reactions (6,22). Figure 3 lists the polyols identified in grapes and also shows structures of components not yet found but likely to be observed should polyol formation from each parent molecule follow an analogous route. 

Mandibular gland secretions of the Colletidae contain blends of monoterpenes. Linalool dominates the mandibular gland secretions of Colletes (Bergstrbm and... 

In addition to aromatic phenolic compounds and sesquiterpenes, the common monoterpenes linalool, p-myrcene and p-ocimene in flower scent have high signaling value for pollinators. Recently it has been calculated that as the result of their reactivity with ozone, these monoterpenes have had their signaling distance to bees... 

Geraniol, nerol and linalool are practically insoluble in water at ambient temperature. Although acid labile, they do not readily react in water at moderate temperature and neutral pH. In unacidified water at 220 °C in the MBR, they reacted within minutes. Geraniol rearranged to a-terpineol (18%) and linalool (16%) predominantly. Lesser amounts of the monoterpene hydrocarbons were also obtained, including myrcene, a-terpinene (10%), limonene (11%), y-terpinene, the ocimenes, a-terpino-lene and alloocimenes (Scheme 2.14) [50],... 

The farnesols and nerolidols are sesquiterpene analogs of geraniol-nerol and linalool. These compounds are formed by extending one of the methyl groups in the 7-position of the corresponding monoterpene with an isoprene unit. Because these compounds have an extra double bond, they also have an additional possibility for cis-trans isomerism. Thus, there are four stereoisomers of farnesol and two of nerolidol. 

These regular monoterpenes constitute a small class which includes the trienes myrcene 4 and ocimenes (5-7) and the alcohols geraniol 15, nerol 16, citronel-lol 17, linalool 18, etc (Structure 4.5). 

Important aroma compounds of black currant berries have been identified mainly by GC-O techniques by Latrasse et al. [119], Mikkelsen and Poll [115] and Varming et al. [7] and those of black currant nectar and juice by Iversen et al. [113]. The most important volatile compounds for black currant berry and juice aroma include esters such as 2-methylbutyl acetate, methyl butanoate, ethyl butanoate and ethyl hexanoate with fruity and sweet notes, nonanal, /I-damascenone and several monoterpenes (a-pinene, 1,8-cineole, linalool, ter-pinen-4-ol and a-terpineol) as well as aliphatic ketones (e.g. l-octen-3-one) and sulfur compounds such as 4-methoxy-2-methyl-butanethiol (Table 7.3, Figs. 7.3, 7.4, 7.6). 4-Methoxy-2-methylbutanethiol has a characteristic catty note and is very important to blackcurrant flavour [119]. 

Parsley (Petroselinum crispum) is a member of the Apiaceae family. The fresh leaves of parsley and the dried herb are widely used as flavouring. More than 80 compounds have been identified in the volatile fraction, and the aromatic volatiles of parsley are mainly monoterpenes and the aromatics myristicin and api-ole. It is suggested that the characteristic odour of parsley is due to the presence ofp-mentha-l,3,8-triene, myrcene, 3-sec-butyl-2-methoxypyrazine, myristicin, linalool, (Z)-6-decenal and (Z)-3-hexenal [227, 228]. Furthermore, /3-phellan-drene, 4-isopropenyl-l-methylbenzene and terpinolene contribute significantly... 

Monoterpenes, 10-carbon-containing terpenoids, are composed of two isoprene units, and found abundantly in plants, e.g. (+)-limonene from lemon oil, and (—)-linalool from rose oil. Many monoterpenes are the constituents of plant volatile oils or essential oils. These compounds are particularly important as flavouring agents in pharmaceutical, confectionery and perfume products. However, a number of monoterpenes show various types of bioactivity and are used in medicinal preparations. For example, camphor is used in liniments against rheumatic pain, menthol is used in ointments and liniments as a remedy against itching, bitter-orange peel is used as an aromatic bitter tonic and as a remedy for poor appetite and thymol and carvacrol are used in bactericidal preparations. 

In the eighties, the bioconversion of monoterpene alcohols by fungi had not been studied intensively [32]. However, a strain of Aspergillus niger was isolated from garden soil, able to transform geraniol, citronellol and linalool to their respective 8-hydroxy derivatives. This reaction was called fu-hydroxylation [39,40]. 

As mentioned before, a Pseudomonas incognita was isolated by enrichment technique on the monoterpene alcohol linalool that was also able to grow on geraniol, nerol and limonene [36]. The metabolism of limonene by this bacterium was also investigated [37]. After fermentation the medium yielded as main product a crystallic acid, perillic acid, together with unmetabolised limonene, and some oxygenated compounds dihydrocarvone, carvone, carveol, p-menth-8-en-1 -ol-2-one, p-menth-8-ene-1,2-diol or p-menth-1 -ene-6,9-diol (structure not fully elucidated) and finally / -isopropenyl pimelic acid. 

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