The essential oil

Unsaturated dicyclic ketone found in the essential oil from the leaves of Umbellularia cali/ornica, with pungent mint-like smell. 

But, safrole is the major component of the essential oil of sassafras which is still quite legal to obtain. Sassafras oil has a strong licorice smell which is imparted to it from the safroie molecule. Commercially, there are two kinds of sassafras... 

OSMORHIZOLE Makes up 25% of the essential oil of chervil. Very hard to find this oil though. 

Specifications. Specifications for many of the essential oils and artificial flavorings are available (66). Physical specifications encourage standardization and uniformity in basic flavor and perfume materials. Although compliance with specifications does not guarantee that flavor quaUty standards will be acceptable, the specifications fill a need and provide a valuable reference for the flavor industry. 

The star anise (I//icium verumHook E.) is from a smaH evergreen tree, native to southwest China. When ripe, the hard brown fmits of this tree open up into an eight-pointed star, hence the name. The flavor and aroma of this spice is similar to that of P. anisum, the essential oils are of similar composition. The uses are similar but more localized. 

Cinnamomum cassia B/um (Lauraceae) is the so-caUed cassia. It is native to southeastern China and has not been grown successfuUy outside of this area. The dried bark of this evergreen tree is stripped, ground, and sold almost exclusively in China. The leaves and twigs of the tree contain the same flavor components as the bark and are steam distUled to yield the cassia oil of commerce. Infrequently, smaU amounts of bark are bundled and exported as cassia lignea but caimot compete with the other varieties as bark spice. The Chinese prefer to seU the essential oil. 

Pommade. These are botanical extracts prepared by the enfleurage method wherein flower petals are placed on a layer of fat which extracts the essential oil. This method is appHed to low odored flowers, which do not yield appreciable oil on steam or water distillation, or flowers of valuable but dehcate odor (such as jasmin), which are destroyed on such treatment. Pommades, as such, are seldom used by the industry at present (ca 1995), but are further processed to provide more concentrated extracts such as absolutes. Absolutes, being alcohol-soluble, are much more convenient forms for the perfumer. 

Resin and Resinoid. Natural resins are plant exudates formed by the oxidation of terpenes. Many are acids or acid anhydrides. Prepared resins are made from oleoresins from which the essential oil has been removed. A resinoid is prepared by hydrocarbon extraction of a natural resin. 

The function of the essential oil in the plant is not fully understood. Microscopic examination of plant parts that contain the oil sacs readily shows their presence. The odors of flowers are said to act as attractants for insects involved in pollination and thus may aid in preservation and natural selection. Essential oils are almost always bacteriostats and often bacteriocides. Many components of essential oils are chemically active and thus could participate readily in metaboHc reactions. They are sources of plant metaboHc energy, although some chemists have referred to them as waste products of plant metaboHsm. Exudates, which contain essential oils, eg, balsams and resins, act as protective seals against disease or parasites, prevent loss of sap, and are formed readily when the tree tmnks are damaged. 

By the thirteenth century AD, essential oils were being produced along with medicinal and herbal preparations in pharmacies. Around this time improvements in distillation techniques were made, in particular the development of the alembic apparatus, which would eventually estabUsh the quaUty of such matenals. As a result, many of the essential oils in use today are denved from those produced in the sixteenth and seventeenth centunes in terms of odor character, even though production methods have continued to evolve. The current practice of aroma therapy is an indication of this common root of medicinal and fragrance chemistry. 

Volatiles or Aroma. The essential oil, or aroma, of tea provides much of the pleasing flavor and scent of green and black tea beverages. Despite this, volatile components comprise only - 1% of the total mass of the tea leaves and tea infusions. Black tea aroma contains over 300 characterizing compounds, the most important of which are terpenes, terpene alcohols, lactones, ketones, esters, and spiro compounds (30). The mechanisms for the formation of these important tea compounds are not fully understood. The respective chemistries of the aroma constituents of tea have been reviewed... 

Terpenes are found as constituents of essential oils and oleoresins of plants. Since antiquity they have been isolated and used in flavor and fragrance apphcations. Many important constituents of the essential oils have been identified and syntheses for them developed (see Oils, essential). 

Gedrene and Gedrol. Cedarwood oil is one of the essential oils whose production is large and provides a source for synthesizing a number of derivatives. Gedrene (91) and thujopsene (92) are the two main sesquiterpene hydrocarbons found in the oil, along with a number of minor components (187). Gedrol [77-53-2] (93) is the main alcohol component of the oil. 

Patchouli alcohol. Patchouli oil comes from Pogostemonpatchouli and the main constituent is patchouli alcohol [5986-55-0] (105) or patchoulol. Another component of the essential oil is norpatchoulenol (106), a norsesquiterpene derivative as a minor (3—5%) constituent, important ia determining the overall odor of the essential oil (197). The price of patchouli oil ia 1995 was 20.90/kg from Indonesia (69). Alarge proportion of the oil (40—60%) is comprised of sesquiterpene hydrocarbons that do not have much odor value. World production of the oil was at about 750 t ia 1984. It is valuable ia perfumery bases because of its characteristic woody, herbaceous odor (198). 

Essential Oils. Volatile oils from plants are referred to as essential oils. The oils can be obtained through steam distillation, solvent extraction, or separation of the oils from pressed fmit. They consist of oxygenated compounds, terpenes, and sesquiterpenes. The primary flavor components of essential oils are oxygenated compounds. Terpenes contain some flavors but are often removed from the essential oil because they are easily oxidized (causiag off-flavors or odors) and are iasoluble. Essential oils are prepared from fmits, herbs, roots, and spices. 

Oleo Resins. These oily residues, obtained from the solvent extraction of herbs, contain more of the characteristic flavors than do the essential oils. The solvent extraction removes nearly all of the flavor bodies from the herb. The extract solvent is distilled, reduciag the solution to an oily residue. Oleo resias of iaterest to the carbonated beverage iadustry are ginger, celery, and black pepper. 

Phenyl-2-propenal [104-55-2], also referred to as cinnamaldehyde, is a pale yeUowHquid with a warm, sweet, spicy odor and pungent taste reminiscent of cinnamon. It is found naturally in the essential oils of Chinese cinnamon Cinnamomum cassia, Blume) (75—90%) and Ceylon cinnamon Cinnamomum lanicum, Nees) (60—75%) as the primary component in the steam distilled oils (27). It also occurs in many other essential oils at lower levels. 

Manufacture. A limited, amount of natural cinnamyl alcohol is produced by the alkaline hydrolysis of the cinnamyl cinnamate present in Styrax Oil. Thus treatment of the essential oil with alcohoHc potassium hydroxide Hberates cinnamyl alcohol of reasonable purity which is then subjected to distillation. This product is sometimes preferred in fine fragrance perfumery because it contains trace impurities that have a rounding effect in finished formulations. 

An in spectmm for identification of coumatin was published by the Scientific Section of the Essential Oil Association of the United States (EOA). Manufacturers specifications for commercial coumatin are (69)... 

Heating or irradiating alkenes in the presence of sulfur gives relatively low yields of thiiranes. For example, a mixture of sulfur and norbornadiene in pyridine-DMF-NHa at 110 °C gave a 19% yield of the monoepisulfide of norbornadiene as compared with a 78% yield by the method of Scheme 120 (79JCS(Pi)228). Often 1,2,3-trithiolanes are formed instead of thiiranes. The sesquiterpene episulfides in the essential oil of hops were prepared conveniently by irradiation of the terpene and sulfur in cyclohexane (Scheme 135) (80JCS(Pl)3li). Phenyl, methyl or allyl isothiocyanate may be used as a source of sulfur atoms instead of elemental sulfur. 

ANALYSIS OF THE ESSENTIAL OIL OF NEPETA SINTENISII BORNM. FROM IRAN... 

Further more, the essential oils of the plant were isolated by hydrodistillation in Clevenger-type apparatus for 5 hours. The chemical compositions of the SFE extract and hydrodistillation were identified by GC-MS and determined by GC-FID. 

It is also known that during the usual procedure for making teas, in the marc left after straining in the case of fennel ca. 70% of the essential oil present in the original drug is left behind, in the case of chamomile as much as 50-70% (with 60-70% of the chamazulene), and in the case of peppermint... 

The 2D chromatograms reveal additional components of the natural mixtures. They also give a map of the essential oil, which is helpful in the identification of the components by the position and the characteristic colours of the derivatives on the plate. A further, considerable improvement in the separation performance can be obtained by using overpressured layer chromatography (OPLC). Harmala et al. (70) used 2D OPLC for the separation of coumarins from the genus Angelica. Figure 10.15 shows the one-dimensional (a) and two-dimensional (b) OPLC separations of 16 coumarins. 

The essential oil from the leaves has been investigated by So Uchida. On distillation vitti steam the green leaves yielded 0 70 per cent, of volatile oil, which was brov.-Qisli.yellow in colour and had a fresh aromatic odour. It has the following characters ... 

The essential oil obtained from the yellow resin, derived from ATon-tharThaa UUiaiiA., was found to contaiu pasonol, and a hydroxypaeonol. 

Pickles aud Karl have made an examination of the essential oil distilled from the fruit of this plant which is alari known as An /mum mcilivm. They find that the oil resides almost entirely in the seeds. By distilling the fruits with steam, aliout 1 per cent, of a pale yellow oil, having an odour cecalliug those of lemon aud eucalyptus, was obtained. The Oil has the following chanteters —... 

The 90-calloJ Nepal sassafras, or Nepal oatnphoi- ti-eo, is probably CinTianicmum Cicindapline. The essential oil t lom the- wood of this ti e has been esatnined by f iokles. ... 

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