Garden Thyme (Thymus vulgaris LINN.)

Thyme, Garden

Botanical: Thymus Vulgaris (LINN.)
Family: N.O. Labiatae

• Description
• Cultivation
• Constituents
• Medicinal Action and Uses

It is cultivated now in most countries with temperate climates, though we do not know at what period it was first introduced into northern countries. It was certainly commonly cultivated in England before the middle of the sixteenth century, and is figured and described by Gerard.

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---Description---T. vulgaris is a perennial with a woody, fibrous root. The stems are numerous, round, hard, branched, and usually from 4 to 8 inches high, when of the largest growth scarcely attaining a foot in height. The leaves are small, only about 1/8 inch long and 1/16 inch broad, narrow and elliptical, greenish-grey in colour, reflexed at the margins, and set in pairs upon very small foot-stalks. The flowers terminate the branches in whorls. The calyx is tubular, striated, closed at the mouth with small hairs and divided into two lips, the uppermost cut into three teeth and the lower into two. The corolla consists of a tube about the length of the calyx, spreading at the top into two lips of a pale purple colour, the upper lip erect or turned back and notched at the end, the under lip longer and divided into three segments. The seeds are roundish and very small, about 170,000 to the ounce, and 24 OZ. to the quart: they retain their germinating power for three years. The plant has an agreeable aromatic smell and a warm pungent taste. The fragrance of its leaves is due to an essential oil, which gives it its flavouring value for culinary purposes, and is also the source of its medicinal properties. It is in flower from May to August.

There are three varieties usually grown for use, the broad-leaved, narrow-leaved and variegated: the narrow-leaved, with small, greyish-green leaves, is more aromatic than the broad-leaved, and is also known as Winter or German Thyme. The fragrant Lemon Thyme, likewise grown in gardens, has a lemon flavour, and rather broader leaves than the ordinary Garden Thyme, is not recurved at the margins, and ranks as a variety of T. serpyllum, the Wild Thyme. It is of a more trailing habit and of still smaller growth than the common Garden Thyme, and keeps its foliage better in the winter, though is generally considered to be not as hardy as the common Thyme. Another variety, the Silver Thyme, is the hardiest of all and has perhaps the best flavour. There is a variety, also, called the Orange Thyme, which Dr. Kitchener, in The Cook's Oracle, describes as a delicious herb that deserves to be better known. This and other varieties of Thyme, including the Caraway Thyme, which was used to rub the baron of beef, before it was roasted, and so came to be called 'Herbe Baronne,' are all worth cultivating.

The name Thyme, in its Greek form, was first given to the plant by the Greeks as a derivative of a word which meant 'to fumigate,' either because they used it as incense, for its balsamic odour, or because it was taken as a type of all sweet-smelling herbs. Others derive the name from the Greek word thumus, signifying courage, the plant being held in ancient and mediaeval days to be a great source of invigoration, its cordial qualities inspiring courage. The antiseptic properties of Thyme were fully recognized in classic times, there being a reference in Virgil's Georgics to its use as a fumigator, and Pliny tells us that, when burnt, it puts to flight all venomous creatures. Lady Northcote (in The Herb Garden) says that among the Greeks, Thyme denoted graceful elegance; 'to smell of Thyme' was an expression of praise, applied to those whose style was admirable. It was an emblem of activity, bravery and energy, and in the days of chivalry it was the custom for ladies to embroider a bee hovering over a sprig of Thyme on the scarves they presented to their knights. In the south of France, Wild Thyme is a symbol of extreme Republicanism, tufts of it being sent with the summons to a Republican meeting.

This little plant, so familiar also in its wild form, has never been known in England by any familiar name, though occasionally 'Thyme' is qualified in some way, such as 'Running Thyme,' or 'Mother-of-Thyme.' 'Mother Thyme' was probably derived from the use of the plant in uterine disorders, in the same way that 'Motherwort' (Leonurus Cardiaca) has received its popular name for use in domestic medicine.

The affection of bees for Thyme is well known and the fine flavour of the honey of Mount Hymettus near Athens was said to be due to the Wild Thyme with which it was covered (probably T. vulgaris), the honey from this spot being of such especial flavour and sweetness that in the minds and writings of the Ancients, sweetness and Thyme were indissolubly united. 'Thyme, for the time it lasteth, yieldeth most and best honie and therefor in old time was accounted chief,' says an old English writer. Large clumps of either Garden or Wild Thyme may with advantage be grown in the garden about 10 feet away from the hives.

Though apparently not in general use as a culinary herb among the ancients, it was employed by the Romans to give an aromatic flavour to cheese (and also to liqueurs).

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---Cultivation---Sow about the middle of March or early April, in dry, mild weather, moderately thin, in shallow drills about 1/2 inch deep, and 8 or 9 inches apart, in good, light soil, in a warm position. Cover in evenly with the soil. Some of the plants may remain where planted, after a thinning for early use, others plant out in the summer. Thyme thrives best with lots of room to spread in. It is well to make new beds annually. Selfsown plants will answer for this where found.

Stocks may also be increased by dividing old roots, or making cuttings, by slipping pieces off the plants with roots to them and planting out with trowel or dibber, taking care to water well. This may be done as soon as the weather is warm enough, from May to September. The old clumps may be divided to the utmost extent and provided each portion has a reasonable bit of root attached, success is assured. The perfume of Lemon Thyme is sweeter if raised from cuttings or division of roots, rather than from seed.

Although Thyme grows easily, especially in calcareous light, dry, stony soils, it can be cultivated in heavy soils, but it becomes less aromatic. It dislikes excess of moisture. To form Thyme beds, choose uncultivated ground, with soil too poor to nourish cereals. If Thyme grows upon walls or on dry, stony land, it will survive the severest cold of this country. If the soil does not suit it very well and is close and heavy, some material for lightening it, such as a little road-sand or sweepings, ensuring reasonable porosity, will be welcomed, and should be thoroughly incorporated - in a gritty soil it will root quickly, but it does not like a close, cold soil about its roots.

According to Gattefosse, the Thyme is 'a faithful companion of the Lavender. It lives with it in perfect sympathy and partakes alike of its good and its bad fortune.' Generally speaking, the conditions most suitable to the growth of Thyme are identical with those favoured by Lavender.

The plant is often overrun by Dodder (Cuscuta epithymum). If this happens, cut off the affected plants and burn them, or use a solution of sulphate of iron.

At the close of the summer, as soon as the herbs have been cut sufficiently, the beds should be attended to, all weeds cleared away and the soil well forked on the surface.

In winter, protect the plants from frost by banking up with earth.

Thyme roots soon extract the goodness from the soil, hence whatever is sown or planted afterwards will seldom thrive unless the ground is first trenched deeper than the Thyme was rooted, and is well manured.

The whole herb is used, fresh and dried. Though cultivated in gardens for culinary use, Common Thyme is not grown in England on a large scale, most of the dried Thyme on the market having been imported from the Continent, mainly from Germany.

Its essential oil is distilled in the south of France, the flowering herb being used for the production of oil of Thyme. In the neighbourhood of Nimes, the entire plant is used and the distillation is carried on at two periods of the year, in May and June, and again in the autumn. In England, only a comparatively small amount of the essential oil is distilled, but it is considered to be of a high quality. For distilling, the fresh herb should be collected on a dry day, when just coming into flower; the lower portions of the stem, together with any yellow or brown leaves, should be rejected and the herbs conveyed to the distillery as soon as possible.

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---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.

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---Medicinal Action and Uses---Antiseptic, antispasmodic, tonic and carminative.

The pounded herb, if given fresh, from 1 to 6 OZ. daily, mixed with syrup, has been employed with success as a safe cure for whooping cough. An infusion made from 1 OZ. of the dried herb to 1 pint of boiling water, sweetened with sugar or honey, is also used for the same purpose, as well as in cases of catarrh and sore throat, given in doses of 1 or more tablespoonsful, several times daily. The wild plant may be equally well used for this.

Thyme tea will arrest gastric fermentation. It is useful in cases of wind spasms and colic, and will assist in promoting perspiration at the commencement of a cold, and in fever and febrile complaints generally.

In herbal medicine, Thyme is generally used in combination with other remedies.

Fluid extract, 1/2 to 1 drachm. Oil, 1 to 10 drops.

According to Culpepper, Thyme is:

'a noble strengthener of the lungs, as notable a one as grows, nor is there a better remedy growing for hooping cough. It purgeth the body of phlegm and is an excellent remedy for shortness of breath. It is so harmless you need not fear the use of it. An ointment made of it takes away hot swellings and warts, helps the sciatica and dullness of sight and takes away any pains and hardness of the spleen: it is excellent for those that are troubled with the gout and the herb taken anyway inwardly is of great comfort to the stomach.'

Oil of Thyme is employed as a rubefacient and counter-irritant in rheumatism, etc.

Thyme enters into the formula for Herb Tobacco, and employed in this form is good for digestion, headache and drowsiness.

In Perfumery, Essence of Thyme is used for cosmetics and rice powder. It is also used for embalming corpses.

The dried flowers have been often used in the same way as lavender, to preserve linen from insects.

In this country, Thyme is principally in request for culinary requirements, for its use in flavouring stuffings, sauces, pickles, stews, soups, jugged hare, etc. The Spaniards infuse it in the pickle with which they preserve their olives.

All the different species of Thyme and Marjoram yield fragrant oils extensively used by manufacturing perfumers for scenting soaps. When dried and ground, they enter into the composition of sachet powders.

THYMOL, a most valuable crystalline phenol, is the basis of the fragrant volatile Essence of Sweet Thyme, and is obtainable from Carum copticum, Monarda punctata and various other plants, as well as from T. vulgaris, being present to the extent of from 20 to 60 per cent in the oils which yield it. Ajowan oil, its principal commercial source (from the seeds of C. copticum) contains from 40 to 55 per cent of Thymol; the oil of T. vulgaris contains from 20 to 30 per cent as a rule of Thymol and Carvacrol in varying proportions, while the oil of M. punctata contains 61 per cent of Thymol.

The extraction of Thymol is effected by treating the oil with a warm solution of sodium hydroxide: this alkali dissolves the Thymol, and on dilution with hot water the undissolved oil (terpenes, etc.) rises to the surface. The alkaline thymol compound is decomposed by treatment with hydrochloric acid and subsequent crystallization of the oily layer into large, oblique, prismatic crystals. Thymol (methyl-propyl-phenol) has been prepared synthetically.

When treated with caustic potash and iodine, it yields iodo-thymol, commonly known as 'Aristol.'

Camphor of Thyme was noticed first by Neumann, apothecary to the Court at Berlin in 1725. It was called Thymol and carefully examined in 1853 by Lallemand and recommended instead of Phenol (carbolic acid) in 1868 by Bouilhon, apothecary, and Paquet, M.D., of Lille.

Thymol is a powerful antiseptic for both internal and external use; it is also employed as a deodorant and local anaesthetic. It is extensively used to medicate gauze and wool for surgical dressings. It resembles carbolic acid in its action, but is less irritant to wounds, while its germicidal action is greater. It is therefore preferable as a dressing and during recent years has been one of the most extensively used antiseptics.

Thymol is also a preservative of meat.

In respect of its physiological action, Thymol appears to stand between carbolic acid and oil of turpentine. Its action as a disinfectant is more permanent and at the same time more powerful than that of carbolic acid. It is less irritating to the skin, does not act as a caustic like carbolic acid, and is a less powerful poison to mammals. In the higher animals it acts as a local irritant and anaesthetic to the skin and mucous membrane. It is used as an antiseptic lotion and mouth wash; as a paint in ringworm, in eczema, psoriasis, broken chilblains, parasitic skin affections and burns; as an ointment, halfstrength, perfumed with lavender, to keep off gnats and mosquitoes. Thymol in oily solution is applied to the respiratory passages by means of a spray in nasal catarrh, and a spirituous solution may be inhaled for laryngitis, bronchial affections and whooping cough. It is most useful against septic sore throat, especially during scarlet-fever. Internally, it is given in large doses, to robust adults, in capsules, as a vermifuge, to expel parasites, especially the miner's worm, and it has also been used in diabetes and vesical catarrh.

Thymol finds no place in perfumery, but the residual oil after extracting the crystalline Thymol from Ajowan oil, which amounts to about 50 per cent of the original oil, is generally sold as a cheap perfume for soap-making and similar purposes, under the name of 'Thymene.'

Till the outbreak of war, Thymol was manufactured almost exclusively in Germany. One of the chief commercial sources of Thymol, Ajowan seed (C. copticum), is an annual umbelliferous plant, a kind of caraway, which is abundant in India, where it is widely cultivated for the medicinal properties of its seeds. Almost the whole of the exports of Ajowan seed from India, Egypt, Persia and Afghanistan went to Germany for the distillation of the oil and extraction of Thymol, the annual export of the seed from India being about 1,200 tons, from which the amount of Thymoi obtainable was estimated at 20 tons. On the outbreak of war the export of Ajowan seed dropped to 2 tons per month, and there was a universal shortage of Thymol, just when it was urgently needed for the wounded.

As a result of investigations by the Imperial Institute, Thymol is now being made by several firms in this country, and the product is equal in quality and appearance to that previously imported from Germany. In India, also, good samples were obtained as a result of experiments conducted in Government laboratories in the early months of the War, and by the close of 1915 companies were already established at Dehra and Calcutta for its manufacture on a large scale. In the two years ending June, 1919, as much as 10,500 lb. of Thymol were exported from Calcutta.

Several other plants can be utilized as sources of Thymol, although none yield such high percentages as Ajowan seed. The following new sources of Thymol were suggested when the scarcity of the valuable antiseptic made itself so severely felt on curtailment of Continental supplies: Garden Thyme and Wild Thyme (T. vulgaris and serpyllum), American Horse Mint (M. punctata), Cunila mariana, Mosla japonica, Origanum hirtum, Ocimim viride and Satureja thymbra.

The oil of Thyme obtained by distilling the fresh-flowering herb of T. vulgaris is already an article of commerce, and contains varying amounts of Thymol, but the actual amount present is not very high, varying, as already stated, from 20 to 25 per cent, only in very rare cases amounting to more; and the methods of separation in order to obtain a pure compound are necessarily more complicated than in the manufacture from Ajowan oil.

The American Horsemint (M. punctata), native to the United States and Canada, seems likely to prove a more valuable source of Thymol than T. vulgaris. It yields from 1 to 3 per cent of a volatile oil, which contains a large proportion of Thymol, up to 61 per cent having been obtained; Carvacrol also appears to be a constituent. The oil has a specific gravity of 0.930 to 0.940, and on prolonged standing deposits crystals of Thymol.

Another species also found in America (M. didyma) (called also 'Oswego tea' from the use sometimes made of its leaves in America) is said to yield an oil of similar composition, though not to the same degree, and so far M. punctata is considered the only plant indigenous to North America which can be looked upon as a fruitful source of Thymol, though from C. mariana, also found in North America, an oil is derived - Oil of Dittany - which is stated to contain about 40 per cent of phenols, probably Thymol.

Thymol is also contained in the oil distilled from the dry herb of Mosla japonica, indigenous to Japan. It is stated to yield about 2.13 per cent of oil, containing about 44 per cent of Thymol.

Satureja thymbra, which is used in Spain as a spice and is closely allied to the Savouries grown in the English kitchen garden, yields an oil containing about 19 per cent of Thymol. Other species of Satureja contain Carvacrol.

A new source of Thymol is also Ocimum viride, the 'Mosquito Plant' of West Africa and the West Indies, which yield 0.35 to 1.2 of oil from which 32 to 65 per cent of Thymol can be extracted. This plant occurs wild on all soils in every part of Sierra Leone, and is also grown in the Seychelles. In Sierra Leone it bears the name of 'Fever-plant' on account of its febrifugal qualities; a decoction is made from the leaves.

The Origanum oils shipped from Trieste and Smyrna generally contain only Carvacrol, the only species yielding Thymol exclusively and to a considerable degree being Origanum hirtum, which may be regarded as a promising source of Thymol.

Recently a Spanish species of Thyme has been used as a source of Thymol (T. zygis, Linn.), known to Theophrastus as Serpyllum zygis. It is common throughout Spain and Portugal, occurring in oak and other woods, in desert and dry gravelly places among the sierras of the central, eastern and southern provinces. In consequence of its wide distribution, the common names for the plant vary greatly; in Portugal it is known as Wood Marjoram, ouregao do mato; but the most frequently recurring name in Spain is Tomillo salsero or Sauce Thyme, from its use as a condiment. The species is very similar to T. vulgaris, but is easily distinguished by the comparatively large white hairs at the base of the leaves. The flowers are either purple or white, the white form being the only one occurring in the Balearic Islands, where it is called Senorida de flor blanca. There are two well-known varieties, var. floribunda and var. gracillis, a simpler, less-branched form, and it is the latter (not such a decided alpine as floribunda) which is now being used by a British manufacturer as a source of Thymol. See Chemist and Druggist, June 12th and July 17th, 1920. Var. gracilis is more easily collected on account of its lower station, and further unguarded exploitation of the wild plant might result in the substitution of var. floribunda, which it seems probable yields an oil with quite different characters and content from those of the oil obtained from var. gracilis.

Carvacrol has not hitherto been employed in medicine, but the antiseptic properties of Origanum oil, consisting principally of Carvacrol, as well as of the phenol itself, have been investigated and Iodocrol - iodide of Carvacrol - a reddish-brown powder, has been used lately as an antiseptic in place of iodoform in treatment of eczema and other skin diseases.

If required, a British Possession can provide Carvacrol as a substitute for Thymol. It can be obtained from oils derived from a variety of plants, but most profitably from the Origanum of Cyprus (Origanum dubium), which contains 82.5 per cent of Carvacrol. At the instance of the Imperial Institute, this Cyprus Origanum oil has been produced in commercial quantities from wild plants in Cyprus, and already in 1913 was exported thence to the United Kingdom to the value of L. (lear) 980. It is believed that the plant can be cultivated profitably and on a large scale in Cyprus, and experiments in this direction were begun shortly after the outbreak of war. The oil from O. onites, var. Symrnaeum - Smyrna Origanum oil - contains 68 per cent phenols, almost wholly Carvacrol. Other sources of Carvacrol are Monarda fistulosa (Wild Bergamot), which yields 52 to 58 per cent of Carvacrol; Satureja montana (Winter Savoury or White Thyme), oil from wild plants of this species containing 35 to 40 per cent of Carvacrol; while that from cultivated plants has been found to contain as much as 65 per cent. A sample of Dalmatian Satureja, a form of S. montana, yielded at the Imperial Institute 68.75 of phenolic constituents, consisting mostly of Carvacrol.

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