Thymol thyme

Thymus vulgaris L. (Thyme) The main component of the essential oil (2.3 %) of partially dried leaves of thyme grown in Kenya was thymol. Thyme oil from other countries is reported to contain thymol (up to 85%) and p-cymene (up to 45%). Thyme is used as a spice due to its apetite stimulating and digestion promotion properties. The oil has strong antimicrobial activity and is also used in the liqueur industiy and as a perfume in soaps, deodorants and hair lotions (34). 

Thyme camphor. See Thymol Thyme extract. See Thyme (Thymus vulgaris), extract... 

The in vitro most antimicrobially active essential oils regularly (or normally) contain substances as main components, which are themselves known to exhibit pronounced antimicrobial properties. These are cinnamic aldehyde (cinnamon bark and cassia oil) and the phenolic compounds eugenol (clove and cinnamon leaf oil) and thymol (thyme oil) (Pauli, 2001). All these essential oils reveal a broadband spectrum of activity in various in vitro test systems (agar diffusion, dilution, and VP) due to their considerable water solubility and volatility. The evaluated antimicrobial inhibitory data of the essential oils obtained in agar dilution tests, serial DIL, and VP tests are summarized in Table 14.81. 

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. 

Lsbhe has eaamiued an antheutic sample of thyme oil and found it to contain 30 [>er oeut. of thymol, 17 per ceut. of a terpeue which he could not I deuiify, 15 per cent, of menthene, 21 per cent, nf cymeue, 5 [>er ceut, of liualol, ft per oent. of borueol, and traces of caiwaerol. 

Thymol, Cj Hj O, is the principal constituent of the oils of thyme and ajotvan seeds. It is isopropyl-mefa-cresol of the constitution—... 

Carvacrol, Cj Hj O, is a phenol isomeric with thymol, with which it is frequently found associated, especially in certain types of thyme and origanum oils. 

In a phenol, a hydroxyl group is attached directly to an aromatic ring. The parent compound, phenol itself, Cr,HsOH (4), is a white, crystalline, molecular solid. It was once obtained from the distillation of coal tar, but now it is mainly synthesized from benzene. Many substituted phenols occur naturally, some being responsible for the fragrances of plants. They are often components of essential oils, the oils that can be distilled from flowers and leaves. Thymol (5), for instance, is the active ingredient of oil of thyme, and eugenol (6) provides most of the scent and flavor of oil of cloves. 

The main constituent of thyme oil is thymol (37-55%) which also determines predominantly the sensory properties of the oil [794-799a]. 

Aromatic monoterpenes which contain a benzene ring like p-cymene 9, car-vacrol 12, thymol 13 and phenylethyl alcohol 14 (Structure 4.4) are common constituents of many essential oils, e.g. oregano (Origanum sp.), thyme (Thymus sp.), savory (Satureja sp.) and rose (Rosa sp.) oils. Another important constituent class of essential oils is phenypropanoids [36]. They are not considered as terpenoids owing to their different biogenetic origins, which will be mentioned later. 

Thyme Thymus vulgaris L., T. zygis Loefl. ex L. Thymol (36-55)... 

Thyme Thymus vulgaris (Lamiaceae) Thymol, carvacrol... 

Alteration of essential-oil components during distillation can be recognized by comparing the oils obtained by steam distillation and by SFE. The hydrolysis of esters (like linalyl acetate) to the corresponding alcohols was observed in clary sage oils. The hydrolysis of thymol bound in glycosides resulted in different thymol concentrations in distilled thyme oils, which was proved by appropriate treatments (acidic and enzymatic) of the previously CO2-extracted plant material. 

Determination of the phenols is of special importance in the analysis of hop (carvacrol), thyme, ajOwan (thymol), aniseed, badiana, fennel (anethole), clove bud and stem (eugenol) and sassafras oils (safrole). 

The aromatic oil extracted from thyme leaves contains thymol and carvacol, which have preservative, antibacterial, and antifungal properties. Thyme is a bronchial antispasmodic that relaxes muscles in the respiratory tract, an effect that makes it a good treatment for bronchitis and whooping cough. Thyme also relaxes smooth muscles in the gastrointestinal tract and the uterus, making it effective as a digestive aid and reliever of menstrual cramps. 

Thymol (isopropyl-m-cresol) is a volatile, phenolic monoterpene produced by several plants including thyme (Thymus vulgaris L.) (Baerheim Svendsen and Scheffer, 1985). Thymol has well-known antiseptic, antifungal, and anthelminthic properties (Wilson et al., 1977) and is also used for food and fragrance applications (Bauer et al., 1990). 

Raw ajowan smells almost exactly like thyme because it also contains thymol, but is more aromatic and less subtle in taste, as well as slightly bitter and pungent. Even a small amount of raw ajowan will dominate the flavour of a dish completely. 

Thymol (2-isopropyl-5-methylphenol) Found in essential oils of thyme and oregano. Strong medicated, herbaceous odour. 

Thyme oil contains thymol and carvacrol (phenols p. 59), which are also dermal irritants, but with linalool and other noncyclic alcohols the risks are significantly reduced. 

When essential oils are described only by their common names, not only do these exclude the importance of the species but they also do not account for the chemotype e.g. thyme might be Thymus vulgaris CT thymol and rosemary might be Rosmarinus officinalis CT camphor (CT after the name of the essential oil describes the chemotype, naming the significant compound within that oil). 

The GC analysis (Fig. 7.7) shows a commercial white thyme with a high percentage of the phenols thymol (55.8%) and carvacrol (2.07%). This contrasts with that of sweet thyme (Fig. 7.8) with no phenolic compounds present and alcohols terpineol-4 (13%), a-terpineol (12.37%) and bomeol (5.95%) making up a total of 31.34% for this particular sample. 

Figure 7.7 Thyme. A typical white Spanish thyme, showing the presence of thymol. Thymol has a retention time of 56.381 min and makes up 55.58% of the oil in this GC analysis of this particular sample. Courtesy of Jenny Warden, Traceability.

Figure 7.8 Thyme. A typical sweet thyme, showing no thymol present. Courtesy of Jenny Warden, Traceability.

Both an aqueous phase and an oily phase (including waxes and essential oils) were extracted from the herbs. These were collected separately as described in the next section. The essential oils in the oily extract were camphor, verbenone, P-myrcene, 1,8 cineole and limonene for Rosemary and thymol, geraniol and geranyl acetate,carvocrol and borneol for Thyme. 

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