THYME

Family: Lamiaceae (Labiatae), Thymus species

Modified from: Simon, J.E., A.F. Chadwick and L.E. Craker. 1984. Herbs: An Indexed Bibliography. 1971-1980. The Scientific Literature on Selected Herbs, and Aromatic and Medicinal Plants of the Temperate Zone. Archon Books, 770 pp., Hamden, CT.

Thyme is the general name for the many herbs of the Thymus species, all of which are small perennial plants native to Europe and Asia. Common or garden thyme, Thymus vulgaris L., is considered the principal type and is utilized commercially for flowering and ornamental purposes. This low-growing woody shrub has gray-green leaves and white, pink, or purple flowers. Thyme is produced and collected in most European countries, including France, Spain, Portugal, and Greece, and in the western United States (11.1-128). The three principal varieties of thyme are English, French, and German, and they differ in leaf shape, leaf color, and essential oil composition.

The reported life zone of thyme is 7 to 255Cdeg;C, with an annual precipitation of 0.4 to 2.8 meters and a soil pH of 4.5 to 8.0 (4.1-31). The plants are adapted to dry, calcareous soils with good drainage. For cultivation, plants are either seeded directly or transplanted. Plants are mulched in northern areas to protect them from winter injury. Harvesting is done during the bloom period. The plant's low-growing habit makes mechanical harvest difficult. Plantings are generally renewed every two or three years, as plants become woody (14.1-29).

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 (14.1-8). Essential oils are extracted by steam distillation. Thyme oil has thymol, terpinen-4-ol, carvacrol, p-cymene, -pinene, camphene, -pinene, myrcene, 1,8-cineole, -terpinene, d-linalool and other compounds (1.5-56, 1.5-57, 6.4-102). Thyme oil is divided into two types, a red, unrectified oil and a white, rectified oil. Oil content of dried plant material is 2 to 5% (4.3-15). An oleoresin is also extracted and commercially available.

Thyme is used for flavoring cheeses, soups, stews, stuffings, meats, fishes, dressings, sauces, and honey. The essential oil and oleoresin of thyme are also used in the flavor and food industries. The oil is used in the flavoring of toothpaste, mouthwashes, and cough medicines. The oil is also used in the manufacture of perfumes and cosmetics. Leaves and flowering tops are used in sachets. Thyme has antioxidant properties (6.4-104, 11.1-128). The plant is grown as an ornamental in rock gardens and along walks, paths, and borders. Thyme plants are attractive to bees, and thyme honey is a well-known and popular variety.

As a medicinal plant, thyme has traditionally been considered an anthelmintic, antispasmodic, carminative, emmenagogue, expectorant, rubefactient, sedative, stimulant, and tonic. The plant has been used as a folk medicine against asthma, arteriosclerosis, colic, bronchitis, coughs, diarrhea, and rheumatism. Thyme has been used to promote perspiration. Thymol is a powerful antiseptic, considered to be quite toxic (11.1-96, 11.1-136). The plant and essential oil can cause contact dermatitis and may affect lipid metabolism (7.6-210, 8.2-79). Thymus species have been used as a folk remedy against cancer (14.1-16).

More than three hundred species of thyme and many hybrids, varieties, and ecotypes exist (14.1-4). Spanish thyme, Thymus zygis L., is a short, erect shrub found and collected wild in the Iberian peninsula of Spain and used in the production of Spanish thyme oil. Wild thyme, Thymus serpyllum L., formerly, Thymus augustifolius Pers., is a prostrate, small, creeping perennial that has a woody stem at the base of the plant. This herb, also known as creeping thyme or mother-of-thyme, is a native of Europe and used primarily as an ornamental. Lemon thyme, Thymus X citriodorus (Pers.) Schreb. ex Schweigg. and Korte, is a many-branched, lemon-scented shrub cultivated as a culinary herb. The lemon thyme plant has a semi-erect stem adaptable to mechanical harvest and is the principal thyme of commerce after common thyme (11.1-128). Thymus capitatus Hoffmg et Link, native to Israel and other Middle Eastern and Mediterranean countries, is used locally as an oregano and was used medicinally against bronchial asthma in early Colonial America (7.7-4). Thymus nummularius, T. pannonicus, T. praecox, T. pseudolanuginosis, and T. pulegioids are smaller thymes used as ornamentals (14.1-4). Thymus praecox subsp. arcticus (E. Durand) Jalas is a popular low-growing, creeping thyme, available with many flower colors and used as a ground cover. Thymbra spicata L., native to Israel and other Mediterranean countries, is a locally used herb with a thyme-like odor.

Thymus vulgaris L. and Thymus serpyllum are generally recognized as safe for human consumption as flavorings, seasonings, and essential oils//oleoresins; Thymus capitatus Hoffmg. et Link, as flavorings or seasonings; and Thymus zygis L. as essential oil/oleoresin (21 CFR sections 172.515, 182.10, 182.20 [1982]).

[Note: References listed above in parentheses can be found in full in the original reference].

Last modified 6-Dec-1997