Thymus vulgaris and Thymus extract.
Article Content:
- .Botanical Info of Thymus vulgaris.
- .Plant Description and Origin.
- .Etymology:Thymus vulgaris.
- .Constituents and Phytochemicals.
- .Culinary Uses and Taking thyme.
- .Medicinal Uses and Functions.
- .Thyme Dosage Information.
- .Identified Applications.
- .Research Update:Thymus vulgaris.
Constituents and Phytochemicals.
Main constituents:
The content of essential oil varies drastically with climate, time of harvest and storage conditions; extreme values are 0.75% and 6.5%. Main components are the phenols thymol (ca. 40%) and carvacrol (ca. 15%). In winter, phenol content is lower (but mostly thymol); in summer, more phenols (up to 70%) are found, with significant amounts of carvacrol. Further components in the essential oil are thymol methyl ether (2%), cineol, cymene, alpha-pinene, borneol and esters of the latter two.
Lemon thyme, Thymus citriodorus, was found to contain an essential oil rich in geraniol (up to 60%); other compounds identified include geranyl esters, nerol and citronellol. The lemon fragrance is due to citral (14%), and thymol was found in small (0.5%) yet not insignificant amounts. (Flavour Fragrance Journal, 10, 225, 1995)
Known primary constituents of Thyme include essential oil (borneol, carvacrol, cymol, linalool, thymol), bitter principle, tannin, flavonoids (apigenin, luteolin), saponins, and triterpenic acids.
The essential oils of thyme are grouped into three main types: thyme oil, which contains 42 to 60% phenols and is mainly thymol; origanum oil, which contains 63 to 74% phenols and is mainly carvacrol; and lemon thyme oil, which contains citral. Thyme oil is divided into two types, a red, unrectified oil and a white, rectified oil. An oleoresin is also extracted and commercially available. Both the essential oil and oleoresin of thyme are used in the flavour and food industries. As a pharmaceutical, the oils thymol and carvacrol are used in mouthwashes, toothpastes, soaps, creams, salves, lotions, liniments, throat lozenges, and cold remedies. The oil is also used in the manufacture of perfumes and cosmetics.
Oil Constituents:
Oil of Thyme is the important commercial product obtained by distillation of the fresh leaves and flowering tops of T. vulgaris. Its chief constituents are from 20 to 25 per cent of the phenols Thymol and Carvacrol, rising in rare cases to 42 per cent. The phenols are the principal constituents of Thyme oil, Thymol being the most valuable for medicinal purposes, but Carvacrol, an isomeric phenol, preponderate in some oils. Cymene and Pinene are present in the oil, as well as a little Menthone. Borneol and Linalol have been detected in the high boiling fractions of the oil and a crystalline body, probably identical with a similar body found in Juniper-berry oil.
Two commercial varieties of Thyme oil are recognized, the 'red,' the crude distillate, and the 'white' or colourless, which is the 'red' rectified by re-distilling. The yield of oil is very variable, from 2 per cent to 1 per cent in the fresh herb (100 lb. of the fresh flowering tops yielding from 1/2 to 1 lb. of essential oil) and 2.5 per cent in the dried herb, the yield of oil from the dried German herb being on the average 1.7 per cent and from the dried French herb 2.5 to 2.6 per cent. The phenols present in French and German oils consist mainly of Thymol, but under certain conditions the latter may be replaced by Carvacrol. The value of Thyme oil depends so much upon the phenols it contains, that it is important that these should be estimated, as the abstraction of Thymol is by no means uncommon.
Red oil of Thyme is frequently imported and sold under the name of oil of Origanum: it is often adulterated with oils of turpentine, spike lavender and rosemary, and coloured with alkanet root, and is not infrequently more or less destitute of Thymol. True oil of Origanum is extracted from Wild Marjoram, Origanum vulgare, and other species of Origanum.
French oil of Thyme is the most esteemed variety of the oil known. A considerable quantity of Thyme oil is also distilled in Spain, but probably from mixed species of Thyme oil, the origin of Spanish Thyme oil not having been definitely proved; a certain amount is also distilled in Algeria from T. Algeriensis. French oil (specific gravity 0.905 to 0.935) contains 20 to 36 per cent of phenols, chiefly Thymol, on which the value of the oil chiefly depends. Spanish oil contains a much higher percentage of phenols, 50 to 70 per cent, mostly Carvacrol, but sometimes a fairly large proportion of Thymol is present. The production of Thymol or Carvacrol seems to depend on some variation in the soil or climatic conditions which favours the formation of one or the other. The specific gravity of Spanish oil is 0.928 to 0.958.
T. capitans also yields an oil of a specific gravity about 0.900, closely resembling that obtained from T. vulgaris. A similar oil is obtained from T. camphoratus. A somewhat different oil is obtained from the Lemon Thyme, T. serpyllum, var citriodorus. This oil has an odour resembling Thyme, Lemon and Geranium. It contains only a very small amount of phenols. Admixture with the oil of T. serpyllum does not alter the specific gravity of Thyme oil. T. mastichina, the so-called Spanish Wood Marjoram, also yields an oil of Thyme, of a bright yellow colour, turning darker with age and with a camphoraceous odour like Thyme.
Composition:Leaves (Dry weight) - Water: 7.8 Calories: 276 Protein: 9.1 Fat: 7.4 Carbohydrate: 63.9 Fiber: 18.6 Ash: 11.7 Calcium: 1890 Phosphorus: 201 Iron: 123.6 Magnesium: 220 Sodium: 55 Potassium: 814 Zinc: 6.2 Vitamin A: 3800 Thiamine: 0.51 Riboflavin: 0.4 Niacin: 4.94
Chemical composition of Albanian thyme oil (Thymus vulgaris L.):
The essential oils of the Albanian thyme (Thymus vulgaris L.) were obtained by steam distillation of air-dried plant material and examined by GC and GC/MS. Over 86 compounds were detected in the oils, from which more than 40 could be identified. The main components identified were: p-cymene: (7.76-43.75%), G-terpinene (4.20-- 27.62%), thymol (21.38-60.15%), carvacrol (1.15-3.04%) and Beta-caryophyllene (1.30-3.07%).
Chemical composition of essential oil from Thymus vulgaris hybrid:
A sample of essential oil obtained from aerial parts of the Thymus vulgaris hybrid known as 'Porlock' (Labiatae) was examined by GC and GC/MS. Twenty-five compounds were identified representing about 94% of the oil with thymol (39.1%), [beta]-caryophyllene (11.1%) and p-cymene (10.5%) as major constituents.
Active Compounds:
Volatile oil, of highly variable composition; the major constituent is thymol, with lesser amounts of carvacrol, with l,8-cineole, borneol, geraniol, linalool, bornyl and linalyl acetate, thymol methyl ether and a-pinene.
Flavonoids; apigenin, luteolin, thymonin, naringenin and others
Miscellaneous; labiatic acid, caffeic acid, tannins etc.
Reference:
1.Thymus vulgaris and Thymus extract.
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