Oil Fennel

CioHi O. White leaflets, with a strong smell and sweet taste, m.p. 22 C, b.p. 235 C. The chief constituent of anise and fennel oils and other essential oils, from which it is manufactured. It can also be prepared from anisole (meihoxybenzene). It is widely used for flavouring pharmaceuticals and dentifrices, and in perfumery. 

APIOLE 23% of celery leaf oil, up to 30% in parsley leaf and seed oils, and in small amounts in cubeb, dill and fennel oils. 

METHYLCHAVICOL Up to 80+% in most basil, chervil and fennel oils. In small amounts in star anise and wormwood. 

Fotnicvlvm piptrihim yields an oil Sicilian Jtmicl mil of specific gravity ahont -9M. Spanish fennel oils, when pnre, do not differ maleri-ally from other genuine sweet and biller fennel oils. Rnl much of the commercial Spanish oil is a mixtaro distilled from the so-callcd vild, and other fennel spi-cies. 

Macedonian fennel yields a verv similar oil. Wild bitter fennel, growing in France, Spain, and Algeria, yields an oil of specidc gravity 0-90.5 to 0 92.5 and an optical rotation up to 50. ft is practically free from anethol. Indian fennel oil has a specific gravity "970 and au optical rotation + 21°. 

Tardy ha.s examined an Algerian oil of specific gravity 0 991 and optical rotation +62°. He found present pinene, pliellandrcne, isnehone, mcthyl-chavicol, auethol, a sesquiterpene, and a little thymo-hydroquinotie. Scliimmcl A Co. find camphene in fennel oil, but are not able to confirm the presence of cymene. Traces ol basic com-ponnds were also detocted. 

Wild bitter fennel oil differs considerably from the ahcve-described oils. Its specific gnivily varies from 0 L05 to 0 925, aud optical rotation + 40° to + 66 - -Anethol is present onlv in traces, but a [air amount of phellandrene is present. Tardy isolated from this oil a crystalline compound melting at 213", which is possibly di-para-1 Bull. Sat. Chin., xvil, 660. 

Saidician s - t-fennel oil has been found to contain p-cymene. 

He found that the d-phellandrene from elemi and bitter fennel oils were identical, and that i-phellandrene from eucalyptus oil is the laevo-rotatory variety of the same terpene. To these he assigned the names d-a-phellandrene and i-a-phellandrene. The d-phellandrene from water fennel oil differs from these and is named d-/3-phellandrene. The following are the characters of the purest specimens of natural phellandrene yet obtained —... 

Fenchone, Cj Hj O, is found in fennel oil and in the oil of Lavandula Stoechas, in its deirtro-rotatory form, and as laevo-fenchone in oil of thuja leaves. It can be extracted from these oils by treating the fraction boiling at 190° to 195° with nitric acid, or permar anate of potassium, and then steam distilling the unaltered fenchone. 

Anethol (isoestragol, methyl-y-oxy-propenyl-benzene) is the principal constituent of aniseed and star aniseed oil, and occur to a considerable extent in fennel oil. It is a crystalline solid, having the characteristic odour of aniseed oil, and possessing the following characters —... 

Mention has already been made of the fact that thujone and fenchone do not react with sodium sulphite consequently the method is useless for tansy, thuja, wormseed, and fennel oils. 

Fenchel, m. fennel, -geruch, m. fennel odor, -holz, n. sassafras wood, -ttl, n. fennel oil, -wasser, n, (Pharm.) fennel water, Fenchocamphersaure, /, fenchocamphoric acid. Fenster, n, window, -glasi n, window glass, -glimmer, m. muscovite, -kitt, m. glaziera putty,... 

The two enantiomers of fenchone occur in a number of essential oils. Optically pure (15) (-f)-fenchone has been detected in bitter fennel oil Foeniculum vulgare var. vulgare) and in sweet fennel oil F. vulgare var. dulce) from various sources.It has also been reported to exist in... 

Fenchone is used to prepare artificial fennel oils and to perfume household products. 

C10H12O, Mr 148.20, tranx isomer pioi.vkPa 234°C, pi.6kPa H5°C, df 0.9883, 1.5615, occurs both as its cis and trans isomers in nature however, /ran -anethole is always the main isomer. Anethole occurs in anise oil (80-90%), star anise oil (>90%), and fennel oil (80%). 

Anethole can be crystallized from oils in which it occurs as a major component (star anise and sweet fennel oils), and estragole containing oils (e.g., basilicum oil). 

The oil was formerly produced in many countries, mainly in eastern Europe, but has now been replaced, to a large extent, by the less expensive star anise and fennel oils which also contain a high percentage of anethole. 

Fennel oil is obtained by steam distillation of the the aerial parts of Eoeniculum vulgare Mill. ssp. vulgare var. vulgare (bitter feimel). It is a colorless to pale yellow liquid with a camphoraceous sweet-spicy odor and a slightly bitter sweet... 

Fennel oil is mainly used in flavoring oral care products and in pharmaceutical preparations. A reasonably quantity of fennel oil is used for the production of pure anethole for flavouring alcoholic beverages (anise liqueurs) [513dj. FCT 1976 (17) p.529 [8006-84-6], [84625-39-8]. 

Chlorophylls are also present in many oleoresins. By fractionation of fennel oil in two separators in series, the pigments precipitate in the first separator [80]. The effects of the extraction parameters on chlorophyll concentration are shown in Table 9.6-4. Increasing extraction pressure and/or temperature favour the dissolution of the pigments. 

The determination of aldehydes and ketones is of importance in the analysis of those essential oils characterised especially by aldehydic or ketoruc principles, e g.,the citral contained in lemon and lemongrass oils, citronellal in citronella Oil and some eucalyptus oils, benzaldehyde in bitter almond oil, salicylaldehyde in meadow-sweet oil, anisaldehyde in aniseed and fennel oils, cuminaldehyde m cumin oil, cinnamaldehyde in cinnamon oil, carvone in caraway oil, pulegone in pennyroyal oil and methyl nonyl ketone in rue oil The determination of the aldehydes and ketones presents, however, difficulties and the above methods are moderately exact in only a few cases, especially when the content of aldehydes or ketones is considerable The bisulphite method is applicable particularly to the determination of cinnamaldehyde and benzaldehyde in cinnamon oil and bitter almond oil, and, up to a certain pomt, to that of citral in lemongrass Oil. The sulphite method gives good results in the same cases and for the determination of carvone and pulegone... 

Fennel oil contains anethole and fenchone, which reduce bloating and in higher concentrations act as antispasmodics. 

It is made by the oxidation of anethole (the chief constituent of anise, star anise, and fennel oils). 

Table 12.3. Composition of fennel oils from flowers and seeds.

Fennel oleoresin is prepared by solvent extraction of whole seeds and normally contains a volatile oil of 50% or a guaranteed content in the range of 52-58%. Only small quantities are produced for specific uses as it is not a substitute for fennel oil. Chemical analysis by Barazani et al. (2002) of the volatile fraction of oleoresins from fruits of seven natural populations of F. vulgare var. vulgare (bitter fennel) from the wild and after cultivation indicated the presence of two groups of populations. Chemotypic differentiation (relative contents of estragole and trans-anethole) or phenotypic plasticity increases within-species chemical variability, but the specific ecological roles of these essential oils remain to be uncovered. 

The maj or characteristics of commercial-grade fennel oil are specific gravity (25°C), 0.953-0.973 refractive index (20°C),1.528-1.538 optical rotation (23°C), +12° to +24° slightly soluble in water, soluble in 1.0 volume 90% or 8 volumes 80% alcohol, very soluble in chloroform and ether. 

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