Carvone caraway

Enantiomers can have striking differences however m properties that depend on the arrangement of atoms m space Take for example the enantiomeric forms of carvone (R) (—) Carvone is the principal component of spearmint oil Its enantiomer (5) (+) carvone is the principal component of caraway seed oil The two enantiomers do not smell the same each has its own characteristic odor... 

There are interesting examples of enantiomers that not only are found separately but also have different chemical properties when reacting with some reagent which is itself an enantiomer. For example (+ )-glucose is metabolized by animals and can be fermented by yeasts, but (—)-glucose has neither of these properties. The enantiomer ( + )-carvone smells of caraway whereas (—)-carvone smells of spearmint. 

Other synthetics with cost advantages and large volume productions are L-carvone [6485-40-17, the primary component in natural spearmint essence D-carvone [2244-16-8], the primary component in natural diU and caraway anethol [4180-23-8], in place of anise and fennel spices and smaller amounts of thymol [89-83-8] replacing thyme and disulfide synthetics for onion and gadic. AH of these synthetics must be labeled as artificial which may limit their use among consumers. 

Caraway Seed. This spice is the dried ripe fmit of Carum carvi L. (UmbeUiferae). It is a biennial plant cultivated extensively in the Netherlands and Hungary, Denmark, Egypt, and North Africa. The seed is brown and hard, about 0.48 cm long, and is curved and tapered at the ends. It is perhaps the oldest condiment cultivated in Europe. The odor is pleasant and the flavor is aromatic, warm, and somewhat sharp (carvone). Caraway is used in dark bread, potatoes, sauerkraut, kuemmel Hqueurs, cheese, applesauce, and cookies. 

The oil possesses moderate antibacterial and strong antifungal properties. Thus the appHcation of the oil to the cmst of cheese could serve to prevent the formation of mycotoxia ia the cheese. The optical purity of the carvone ia caraway has been determined usiag a chiral gc column (72). It was found to be (i )(+) = 97.64% and (5 )(—) = 2.36%. 

Absorption, metaboHsm, and biological activities of organic compounds are influenced by molecular interactions with asymmetric biomolecules. These interactions, which involve hydrophobic, electrostatic, inductive, dipole—dipole, hydrogen bonding, van der Waals forces, steric hindrance, and inclusion complex formation give rise to enantioselective differentiation (1,2). Within a series of similar stmctures, substantial differences in biological effects, molecular mechanism of action, distribution, or metaboHc events may be observed. Eor example, (R)-carvone [6485-40-1] (1) has the odor of spearrnint whereas (5)-carvone [2244-16-8] (2) has the odor of caraway (3,4). 

The constituents recognised in caraway Oil are carvone. (i-limonene, dihvdrocarvom-, oai veol, and dibydrocurVcol, and Sp base having a nainoiic odour which hn.s not been investigated. 

Carvestrene, or i-sylvestrene, was first prepared by Baeyer from carvone, the ketone characteristic of oil of caraway. This body, when reduced with sodium and alcohol yields dihydrocarveol, which, on oxidation is converted into dihydrocarvone. The formulae of these three bodies are as follows —... 

Dihydrocarveol, Cj H gO, is a natural constituent of caraway oil, and is also obtained by the reduction of carvone. 

The above values apply to natural dihydrocarveol from caraway oil. A specimen prepared by the reduction of carvone had a specific gravity 0-927 at 20° and refractive index 1-48168. i (r.ii4.j... 

Carvone, CjjHj40, is the ketone characteristic of dill and caraway oils. It occurs in the dextro-rotatory form in these oils, and as laevo-carvone in kuromoji oil. 

By reduction carvone fixes 2 atoms of hydrogen on to the ketonic group, and 2 atoms in the nucleus, with the formation of dihydrocarveol, CijHjgO, whose corresponding ketone, dihydrocarvone, Cj Hj O, exists in small quantities in caraway oil. 

Numerous examples of the different biological effects of enantiomers are available. One of the enantiomers of limonene smells of lemons, the other of oranges one of carvone smells of caraway, the other of spearmint These differences obviously have important... 

The main constituents of spearmint oil are /-carvone (Fig. 13.12.7) and /-limonene (Fig. 13.12.8). Oil of spearmint contains from 45 to 60% l-carvone, 6 to 20% of alcohols, and 4 to 20% of esters and terpenes, mainly /-limonene and cineole (see Fig. 13.12.4)J2J The optically isomeric form of carvone, d-carvone, is found in oil of caraway and oil of dill. Carvone appears to co-occur with limonene when present in a plant. 

The mammalian olfactory system possesses enormous discriminatory power. It is claimed that humans can perceive many thousands of different odorous molecules, termed odorants. Even slight alterations in the structure of an odorant can lead to profound changes in perceived odor quality. One commonly cited example is carvone, whose L- and D-stereoisomers are perceived as spearmint and caraway, respectively. However, more subtle molecular alterations can also generate striking changes in perception. 

At the cellular level, the various types of receptor, transporter, enzyme and ion charmel are all chiral in form. Thus although the enantiomers of a drug may have identical physicochemical properties, the way in which they may interact with chiral targets at the level of the cell will give rise to different pharmacod)mamic and pharmacokinetic properties. A few simple examples will illustrate how taste and olfactory receptors can differentiate between enantiomers. Thus R-carvone tastes like spearmint whereas the S-isomer tastes like caraway. Similarly, R-limolene smells like lemon whereas the S-enantiomer tastes of orange. 

The major constituent of caraway oil is (+)-carvone, and the typical caraway odour is mainly due to this component. On the other hand, the typical minty smell of spearmint oil is due to its major component, (—)-carvone. These enantiomers are unusual in having quite different smells, i.e. they interact with nasal receptors quite differently. The two enantiomeric forms are shown here in their half-chair conformations. 

Ravid U, Bassat M, Putievsky E, Weinstein V, Ikan R, Isolation and determination of optically pure carvone enantiomers from caraway Carum carvi L.), diU Anethum aveolens L.), spearmint Mentha spicata L.) and Mentha longifolia (L.) Huds, Flavour Fragr J 2 95-97, 1987. 

Ravid U, Putievsky E, Katzir I, Weinstein V, Ikan R, Chiral GC analysis of (5)(- -)- and (i )(—)-carvone with high enantiomeric purity in caraway, dill and spearmint oils. Flavour Fragr/7 289—292, 1992. 

Bouwmeester HJ, Davies JAR, Toxopeus H, Enantiomeric composition of carvone, limonene, and carveols in seeds of dill and annual and biennial caraway YiLnexies, JAgricFood Chem 43 3057-3064, 1995. 

Figure 2.1 Examples of chiral molecules where the enantiomers have different biological activity. ( -Carvone tastes of caraway while the (R)-enantiomer tastes of spearmint. The (S)-form of asparagine tastes...

Production. In the past, (+)- and (-)-carvones were isolated by fractional distillation of caraway oil and spearmint oil, respectively. However, these carvones are now prepared synthetically, the preferred starting material being (+)- and (-)-limonenes, which are converted into the corresponding optically active carvones. Since optical rotation is reversed in the process, (+)-limonene is the starting material for (—)-carvone. 

The major constituents of common caraway oil are (+)-limonene and (+)-car-vone, which together may make up more than 95% of the oil. (+)-Carvone is the essential odor component. 

Dill seed oil is prepared by steam distillation of the crushed ripe fruits of the dill plant. Its main components are limonene (up to 40%) and (+)-carvone (up to 60%) [486]. In contrast to the weed oil, this oil has a typical caraway odor and taste which is characteristic of (+)-carvone. 

Spirit drinks which are produced by flavouring ethyl alcohol of agricultural origin with distillates of caraway or dill are called akvavit or aquavit and mainly come from Denmark and Scandinavia these spirits are flavoured using neutral alcohol distillates of caraway (Carvum carvi) and/or dill Anethum graveolens) the use of essential oils is prohibited. The impact compounds of these spirits are f+j-carvone and anethol. 

Limonene is a monoterpene that occurs in citrus fruits. Two enantiomers of limonene produce two distinct flavours (—)-limonene is responsible for the flavour of lemons and (+)-limonene for orange. Similarly, one enantiomeric form of carvone is the cause of caraway flavour, while the other enantiomer has the essence of spearmint. 

Caraway Carum carvi (Apiaceae) (-l-)-carvone, (+)-hmonene... 

Carum carvi L. Ye Hao (Caraway) (fruit, aerial part) Essential oil, d-carvone, coumarin, chromone, polyacetylene, hemiarin, scopoletin, umbelliferone, d-limonene, phytosterols.48-50-250-450 Carminative, treat stomach pain. 

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