Herb oils, thymol from

However, the composition of the volatile oil obtained from the herb also differs markedly from that of the seeds. Eleven components out of 21 are similar in both herb and seed oils, while some differences have been observed between the relative amounts of /J-pinene, a-terpinene, p-cymene, a-terpineol, perilla aldehyde, thymol, a-cis-bergamotene, acoradiene and... 

Thymol (169) is found in a number of species, mostly from the Thymus, Ocimum, and Monarda families. It takes its name from thyme (T. vulgaris) of which it is an organoleptically important component. The levels present vary widely not only from species to species, but also from plant to plant within a species. As it is a phenol, it can be extracted from herb oils using aqueous sodium hydroxide and subsequent acidification. Such techniques were used to produce thymol in the past, particularly from thyme, oregano, and basil. Material isolated in this way tended to contain some carvacrol (213). This is a disadvantage as the medicinal, phenolic, and tarry odor of carvacrol spoils the sweeter, herbal, and medicinal odor of thymol. Since thymol is easily prepared, as described above under menthol, the modem supply is entirely synthetic, mostly from Symrise. The major use for thymol is as an intermediate for menthol production. 

Villanueva et al. reported a comparison between the performance of different green solvents for extracting thymol from different thyme plants. The genus Thymus (Lamiaceae family) is an aromatic plant very rich in essential oil compounds, which are the most valued constituents of the herb. Thyme essential oil is formed by terpenes and its oxygenated derivative compounds (alcohols, aldehydes, ketones, etc.) and is appreciated for food flavoring, in cosmetic, perfumery and in the pharmaceutical industry. 

Villanueva et concluded that any of the three green liquid solvents studied, namely ethanol, ethyl lactate and limonene, can efficiently extract thymol from thyme plants, with limonene being the solvent that produced the highest concentrations, due to its lipophilic character. Although PLE produced similar thymol recovery than SEE, considerably higher concentrations of thymol were obtained by SFE-CO2 (up to 31.0 wt%) supporting the selective extraction of volatile oil compounds from plants and herbs using SFE-CO2. 

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. 

Oregano Origanum virens L. is an perennial herb with 40-70 cm high and very aromatic. This plant grows in open and dry countries, at altitudes lower than 500-700 m. The major components of essential oil from Origanum virens L. are terpineol, a-pinene, camphor, thymol, carvacrol and cineole. Compounds such as alcohols and dipentene are also present. 

Phytochemistry The herb contains essential oil (with phenols such as thymol and isomers of carvacrol), bi and tricyclic sesquiterpenes, free alcohols, tannins, ascorbic acids, and flavonoids (Akopov 1990 Sivropoulou et al. 1996). A total 62 constituents were identified from the essential oil of Origanum vulgare ssp. vulgare, with the main constituents being caryophyllene, spathulenol, germacrene-D, and terpineol (Sahin et al. 2004). 

Parsley herb (leaf) oil contains myristicin (up to 85% in the curly moss variety), P-phellandrene, 1,3,8-p-menthatriene, myrcene, apiole, terpinolene, and l-methyl-4-isoprope-nylbenzene as major components. Other compounds present include a- and P-pinenes, fra 5-p-ocimene, y-terpinene, methyl disulfide, a-terpineol, a-copaene, caryophyllene, and carotol, among others.An assessment of 104 accessions found leaf oil content to range from 0.00% to 0.16% (fresh weight). Major constituents were 1,3,8-p-menthatriene (68%), myristicin (60%), P-phellandrene (33%), apiol (22%), myrcene (16%), plus terpinolene and l-methyl-4-isopropenylben-zene at 13%. Thymol, first reported for the leaf oil, was found at 2% or less in seven samples. More than 45 components have been reported from parsley leaf oil. ... 

Thymol (26) and carvacrol (27), isolated from herbs such as thyme and savory, are members of the menthane family in which the cyclohexane structure has been oxidized to an aromatic (phenolic) ring. Oils containing these phenolic terpenes have been shown to be particularly effective as antibacterial agents (Kalemba and Kimicka 2003). 

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