Essential oils components

Martinek [182] has described the reverse procedure for relatively volatile substances (e.g. essential oil components), where the compound to be detected is "distilled onto the reagent plate and reacts with the reagent there. 

Phosphomolybdic acid essential oil components stabilization of the silver nitrate-impregnated adsorbent layer [207]... 

Fig. 1 Schematic sketch (A) of the separation of essential oil components (ca. 500 ng of each component) and reflectance scan of the mixture (B). Menthol (1), caryophyllene epoxide (2), thymol (3), menthyl acetate (4), caryophyllene (5), mixture (G).

C. Bicchi and A. Pisciotta, Use of two-dimensional gas cliromatography in the dkect enantiomer separation of chkal essential oil components , J. Chromatogr. 508 341-348(1990). 

Essential oil components 800-900 C Induction of fluorescence in a special apparatus. [18]... 

Sterols, fatty acids, triglycerides, essential oil components [3]... 

Table 1 Essential oil components with hRf value, color and detection limits.

Fig. 5.5 Compounds 425 33, essential-oil components from Conocephalum conicum...

Natural chiral essential oil components generally have a characteristic enantiomeric distribution that is attributable to stereoselectivity — controlled biogenetic formation mechanisms. An excess of one enantiomer or the other occurs and can be detected, in a variety of essential oils and oleoresins. The authentic enantiomeric ratio of some essential oil components can be modified by the addition of synthetic racemic or natural ingredients (adulteration). 

The use of enantiomers as additional markers for taxonomic characterization of aromatic plants may be very helpful. The differences in the enantiomeric distribution of trans- and cis- sabinene hydrates in two Origanum species enable the species to be distinguished in spite of their similar essential oil compositions. A further study on the natural variation of the enantiomeric composition within a wild population may be carried out in order to examine the stability in a taxon (including the possible presence of chemotypes). The enantiomeric ratio of essential oil components is a reliable parameter for assessing quality because it may be indicative of adulteration, contamination, aging, shelf life, technological process and the botanical source of a specific chiral compound. ... 

Bicchi C, Pisciotta A, Use of two-dimensional gas chromatography in the direct enantiomer separation of chiral essential oil components, J Chromato 508 341-348, 1990. 

Peterson CJ, Nemetz LT, Jones LM, Coats JR, Behavioral activity of camip (Lamiaceae) essential oil components to the Gkrman cockroach Blattodea Blat-tellidae). JEcon Entomol95 377—380, 2002. 

ZO067 Haginiwa, ]., M. Harada, and 1. Mori-shita. Pharmacological studies on crude drugs. Vll. Properties of essential oil components of aromatics and their pharmacological effect on mouse intestine. Yakugaku Zasshi 1963 83 624. 

Essential oils are especially important in mutualistic relationships between plants and insects such as pollination and seed and fruit dissemination (37,45,77-79). In these instances essential oil components serve as attractive substances for the plant. These compounds vary widely in composition but contain most of the chemical types described above. In some cases even volatile amines and skatole are involved, as in the pollination of Sauronatum guttatum (Araceae) (80). 

Capillary gas chromatography (GC) using modified cyclodextrins as chiral stationary phases is the preferred method for the separation of volatile enantiomers. Fused-silica capillary columns coated with several alkyl or aryl a-cyclo-dextrin, -cyclodextrin and y-cyclodextrin derivatives are suitable to separate most of the volatile chiral compounds. Multidimensional GC (MDGC)-mass spectrometry (MS) allows the separation of essential oil components on an achiral normal phase column and through heart-cutting techniques, the separated components are led to a chiral column for enantiomeric separation. The mass detector ensures the correct identification of the separated components [73]. Preparative chiral GC is suitable for the isolation of enantiomers [5, 73]. 

Adams RP (2002) Identification of Essential Oil Components by Gas Chromatography/Qua-druple Mass Spectroscopy. Allured, Carol Stream... 

Novak, I., Zambori-Nemeth, E., Horvath, H., Seregely, Z, Kafika, K. (2003) Study of essential oil components in different origanum species by GC and sensory anlysis. Acta Aliment 32 141-150. 

Other compounds, containing sulphur or nitrogen, may be present in some oils (like onion, garlic).Investigations on the solubility of pure essential-oil components in carbon dioxide showed that the separation of terpene hydrocarbons and oxygenated derivatives by fractionated extraction is difficult, since their solubility behaviours and vapour pressures are almost the same. Saturating the CO2 with water as modifier can increase the differences in solubility [78],... 

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