Sesquiterpenes lavender

In general, examinations of intraspecific floral scent indicate considerable variability in scent composition. Most information about qualitative variation within species comes from studies of domestically cultivated flowering plants. For a given species, it is possible that all plants produce flowers that have the same number and type of compounds. This was shown to be the case for the scents of 4 snapdragon cultivars, in which 8 volatile compounds occurred in all cultivars. A study by Kim et al. (2000) reported 41 compounds in the scent of roses including 8 different classes of compounds (alcohols, aldehydes, alkanes, monoterpenes, sesquiterpenes, ethers, esters, and ketones). They examined 3 cultivars and found that each had approximately 30 compounds, but only 19 of those (63%) were found in all 3 cultivars. Another study of 4 cultivars of lavender by Kim and Lee (2002) reported that each produced approximately 28 compounds, with only 14 in common (50%) (Fig. 8.2 and 8.3). ... 

Composition Genuine essential oils consist exclusively of volatile components with boiling points mainly between 150 and 300 °C. They contain predominantly hydrocarbons or monofunctional compounds such as aldehydes, alcohols, esters, ethers, and ketones. Parent compounds are mono- and sesquiterpenes, phenylpropane derivatives, and longer-chain aliphatic compounds. Accordingly, essential oils are relative non-polar mixtures, i.e., they are soluble in most organic solvents. Often the organoleptic properties are not determined by the main components but by minor and trace compounds such as, e.g., 1,3,5-undecatrienes and pyrazines in galbanum oil. In many of the commercially important oils, the number of identified components exceeds 100. Very many of the constituents are chiral, frequently one isomer predominates or is exclusively present, e. g., (- )-menthol in peppermint oils or (-)-linalyl acetate in lavender oil. 

Synonyms Caryophyllene (-)-trans-Caryophyllene 8-Methylene-4,11,1 l-(trimethyl) bicycle (7.2.0) undec-4-ene trans-(1R,9S)-8-Methylene-4,11,11 -trimethylbicycio [7.2.0] undec-4-ene 4,11,11-Trimethyl-8-methylene, bicycle [7.2.0] unclec-4-ene Definition A mix of sesquiterpenes occurring in many essential oils (clove oil, lavender oil, cinnamon leaves, copaiba balsam)... 

FIGURE 7.11 Reconstructed gas chromatographic trace for a lavender essential oil (a) and the 2D separation space for the 2D gas chromatography analysis of the same sample (b). The minor component Z overlaps completely from the major component Y in the D. M, monoterpene hydrocarbons S, sesquiterpene hydrocarbons. (From Shellie, R. et al, J. Chromatogr. A, 970, 225, 2002. With permission.)... 

Lavender oil has been reported to contain more than 100 components, including linalool, linalyl acetate, lavandulyl acetate, terpinen-l-ol-4, 1,8-cineole, camphor, 3-phellandrene, terpinolene, a-thujene, n-hexanal, n-heptanal, methyl amyl ketone, ethyl amyl ketone, perillaldehyde, perillyl alcohol, r/-bomeol, a-terpineol, a-pinene, limonene, lactones (4-butanolide, dihydrocoumarin, 4-methyl-4-vinyl-4-butanolide, 5-pentyl-5-pentanolide, 4,4-dimethyl-2-buten-4-olide, etc.), sesquiterpenes (caryophyllene, cadinene, etc.), fatty acids (propionic acid, isobutyric acid, caproic acid, p-coumaric acid, etc.), and others (list and horhammer). " ... 

The principal difference between English and French oil of lavender is that the foimer contains only a very small quantity of liualyl esters whilst cineol appears to hti a normal constituent of English oil. Semrn-ler and Tiemann have isolated from English oil the terpene limo-nene, linalol, and Idiaalyi acetate. (>ineol and a sesquiterpene are also normal constituents of the oil. 

Our knowledge of the chemlstrj of this oil is chiefly due to-Bouchardai, who showed that it contained pinene and oineol (cuca-lyptol). Later, he proved the presence of camphor, linalol, borncol, and camphene. Terpineol and geraniol are al=o present in small quantities. Probably a sesquiterpene also exists in this oil, but its presence has not yet been definitely proved. The similar it 5 of the odour of this oil 10 true lavender and rosemaiy is easily explained when one considers that... 

---