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makes the leaves dry and ultimately leads to plant death. Mostly it spreads by
infected seeds. To prevent widespread of this disease infected leaves should be
removed from plant. Moreover, proper spacing should be done so that air can properly circulate around the leaves. Thyme plants are also vulnerable to root rot.
Treating thyme plants with hydrogen peroxide reduces the incidence of this disease.
Grey mold is another pathogen damaging thyme plants. It causes discoloration of
thyme leaves. A layer of grey spores is formed on the leaf surface as symptoms of
this disease.
Thyme plants are also frequently attacked by aphids and spiders. Aphids use
phloem sap as their nutrition thus dehydrating the plant. Using biological methods
like releasing larvae of lady bug can reduce the severity of attack. Spraying neem oil
is also an effective remedy. Spider mites also badly destroys thyme crop. Their presence can be witnessed by the presence of spider webs between stems. These are
reddish brown insects inhabiting hot and dry environment similar to one suitable for
growth of thyme. Spider mites are relatives of spiders and mites. They feed on plant
juices thus rendering the leaves yellow and eventually their dropping off. Using
pesticides is of no use as these insects have developed resistance for the variety of
them. Another pathogen Colletotrichum destructivum causes Anthracnose. In this
disease chlorotic lesions form on the surface of leaves which gradually extends
towards the stem. People cultivating thyme in warm and humid climate should
beware of this disease.
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16.4.24 Annual Production
In 2020, 191.45 thousand metric tons of Thyme oil was produced globally. North
America, Latin America. The Middle East and Africa, Europe and the Asia Pacic
region are chief contributors of thyme oil. Red and white thyme essential oil is
available in the market. It is expected that in 2027, the thyme oil market will grow
by 7.8%. In Pakistan, thyme plants are grown in Baluchistan, as the environment
there is feasible for its growth.
16.4.25 Major Producers ofThyme Oil
Since sixteenth century thyme oil is in use. However, the exact record of its extraction dates back to 1930s. For many years 5–10 tons of oil used to be extracted. This
essential oil is of immense importance because of its rich constituents and aromatic
properties. Different species of thyme produces oil rich in different compounds. For
example T. serpyllum produces thyme oil rich in thymol, same is the case with
Thymus zygis L. carvacrol rich thyme oil can be obtained from T. capitates. In
beginning of twentieth century, thyme oil was extracted from Thymus vulgaris L. in
Germany. In Spain, thyme oil is being produced by Thymus zygis L. [21].
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16.4.26 Thyme Market
United States is the biggest market of essential oils followed by Japan and Europe.
Europe is center for essential oils production, with world’s seven largest oil producing rms present there. In US, soft drink manufacturers are biggest consumers of
essential oils. Only world’s 10% essential is used by Japan. These essential oil are
also utilized in perfume and pharmaceutical industries. As France is biggest manufacturer of perfumes and Switzerland leads in pharmaceutical industries, both utilize big quantity of essential oils. For essential oil production, most countries import
dried thyme from Morocco and Spain, the biggest producers of thyme [22].
16.4.27 Chemical Composition ofThyme Essential Oil
Oils are complex mixtures comprising of around 30–60 components mixed in different concentrations (Table16.2). The property of oils is due to various components that are part of it. The essential oil of thyme is responsible for its spicy aroma.
Like all other members of family Lamiaceae, the essential oil of thyme is stored in
its glandular peltate trichomes that are present at both sides of the leaf. The gland
head consists of 8–16 secretory cells. The oil is secreted into the sub-cuticular space
by the secretory cells. Rupturing of cuticle by rubbing or grinding releases the volatile oil into the air thus spreading the spicy aroma of thyme. Around 1–2.5% essential oil is present in dried plant material.
Some of the major constituents of thyme essential oils are Thymol, Carvacrol,
Linalool, Apigenin, Eugenol, p-cymene, γ-terpinene and Rosmarinic acid. Among
the above mentioned 6 chemotypes, thymol is a predominant substance. When
dried, it comprises 2.5% of essential oil [23]. The primary constituents of this oil are
thymol, carvacrol, p-cymene, γ-terpinene, linalool, β-myrcene, terpinene-4-ol [Fig.
16.3]. Thymol is a white crystalline aromatic monoterpenoid phenol and major
compound found in thyme essential oil. It is a strong antiseptic and possess antibacterial and antifungal properties. Carvacrol, another monoterpenoid and an isomer of
thymol is reported to have antithrombic, anti-inammatory and antimicrobial activity. It constitutes 1–5% of thyme oil. Moreover, p-cymene (15–20%) and γ-terpinene
Table 16.2 Chemical constituents of thyme essential oil [26]
Chemical constituents Biological activities
Thymol Antiseptic, antibacterial and antioxidant in nature
Carvacrol Anti-thrombotic, anti-inammatory
Linalool Anti-viral, antioxidant and analgesic in nature
Eugenol Neuro-protective and anti-anaphylactic
Apigenin Anti-cancerous, antiviral and anti-inammatory
Rosmarinic acid Anti-mutagenic and anti-allergic
antimicrobial
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Fig. 16.3 Various chemical structures in Thymus sp.
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(5–10%) are also present. These two are the precursor thymol biogenetic pathway.
Eugenol present in Thymus essential oil is popular for its analgesic effects. It also
possess neuro-protective and anti-anaphylactic properties. Linalool a major constituent of thyme EO and several other essential oils also possess a number of medically important properties. Rosmarinic acid and apigenin both have anti-mutagenic
properties thus attacking cancerous cells. Few partly glycosidic compounds are also
present.
Thymus vulgaris L. is chemically polymorphous species. Today in France seven
genetically different chemotypes of Thymus vulgaris L. are present. They are named
based upon the dominant monoterpene present in their essential oil. In Spain only
two chemotypes are found namely cineole type and linalool type. However, among
all the types thymol chemotype is commercially used. It contains 56.53% of oxygenated monoterpenes and a relatively low concentration of monoterpene hydrocarbons (28.69%), sesquiterpenes about 5.04% and 1.84% of oxygenated sesquiterpenes.
Monoterpenes are responsible for the typical spicy aroma of thyme. The major component of T. vulgaris L. is thymol about 51.34% while the concentration of other
components is less than 19%. According to European Pharmacopoeia, Thymus vul-
garis L. contains 12mL/kg of oil in it. In Spain where Thymus zygis is the major
source of essential oil. Its chemical composition is similar to that of T. vulgaris but
it contains high percentage of thymol. The dried herb of T. serpyllum contains
0.2–0.6% of essential oil. For production at commercial level plant material rich in
phenolic content is needed. The percentage and composition of essential oils in
Thymus species depends upon their genetic makeup, their surrounding environment
together with their agronomic conditions and storage conditions [24].
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16.4.28 Flavonoid Distribution inThyme
Aglycones have been widely found in Thymus species. In Thymus taxa none isoavonoids have been discovered so far. The two avonols found in Thymus genus are
Kaempferol and quercetin. However, avonones are scarcely found. Anthocyanins
are rarely found in this genus [25]. In Thymus species 16 avonoid glycosides have
been reported till date. Flavones apigenin and luteolin are most important avonoids
found in thyme. Till now 9 phenolic compounds are found to be the part of genus
Thymus.
16.4.29 Biphenyl Compounds
Due to their antioxidant properties and deodorant effects biphenyl compounds have
gained signicant importance. From thyme leaves different biphenyl compounds
have been isolated so far. Spectroscopic methods were used for identication of
these compounds.
16.4.30 Biological Activities oftheChemical Compounds
Present inT. vulgaris L.
Commonly known as a yellow oil, Thymus vulgaris L. oil has been found to contain
47 chemical constituents. Thyme oil has been listed among the top ten essential oils
in the world [26]. However, the percentage of thymol is highest in Thymus vulgaris
L.The percentage of these chemical compounds can vary due to the climatic conditions of the geographical region in which the plant grows. The quantity of the oil
may vary because of various factors i.e., plant variety and its health, plant age at the
time of its collection, the methods used for its drying and later for oil extraction.
Research showed that the antimicrobial activity of Thymus oil increases with an
increase in concentration. Moreover, the antifungal activity of thyme oil is also
concentration-dependent. Apart from this, thymol also has antiseptic and antioxidant properties. This antioxidant activity is due high phenolic compounds in Thymus
vulgaris L.Compounds like carvacrol also shows anti- swelling and acetylcholinesterase inhibitory activities. The antiviral effect of linalool compound has also been
reported in thyme oil. Eugenol and apigenin present in thyme oil results in their
antiviral and anti-anaphylactic activities. Rosmarinic acid present in oil has antiallergic, anti-mutagenic and astringent activities.
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16.4.31 Nutritional Value ofThyme
Thyme is very rich in nutrients. These nutrients prevent various diseases and are
healthy for the body. Vitamins minerals and phytonutrients that are vital for good
health are found in Thymus vulgaris L. Thymus also comprises of different percentages of sodium, potassium, calcium, iron, manganese, zinc, riboavin, pyridoxine
and carotene-ß [28].
16.4.32 Vitamins
Thyme is rich in vitamin A and vitamin C [29]. Both vitamins have their nutritional
importance. Vitamin A is an antioxidant that prevents night blindness, helps in keeping mucus membranes healthy and is also essential to keep skin healthy. Vitamin C
helps in keeping the defense mechanism strong. It provides resistance against harmful diseases and keeps the body inammation free. Vitamin B6 or pyridoxine is also
essential for the body and it is recommended to take 27% or 0.35mg of this vitamin
on daily basis. Vitamin B6 is responsible for making antibodies and hemoglobin,
breaking down proteins and for keeping blood glucose levels in the range [27].
Vitamin B6 also acts as a stress buster. Folic acid, vitamin K and vitamin E are also
constituents of Thymus vulgaris L.
16.4.33 Minerals
Thyme is also rich in minerals that are essential to keep the body healthy. Thymus
leaves contain K, Ca, Fe, Mn, Mg and Se that are required by the body to perform
various cellular functions [30]. Selenium is a part of glutathione peroxidase which
functions as an antioxidant enzyme. It converts oxygen free radicals into less toxic
or non-toxic forms. Potassium is an intracellular cation that transmits nerve
impulses, maintains acid-base balance, prevents osteoporosis and helps in keeping
blood pressure lower. Manganese helps in keeping bones strong while iron is
responsible for the formation of red blood cells.
16.4.34 Volatile Oils
Thymol is the major and signicant component of essential oil found in thyme
which is well-known for its activity against bacteria and fungi. Other volatile oils
such as carvacrol, geraneol and borneol are also present in Thymus vulgaris
L.Thymol and carvacrol are the major phenols of this oil. Whereas linalool and
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p-cymene are non-phenolic components of thyme oil [31]. In addition aromatic
terpenes, terpenoids and avonoids are also a part of thyme essential oil.
Hybridization and polyploidization are responsible for the presence of diverse
compounds in different species of thyme. The chemical makeup and isolation
yield of essential oil are dependent upon the ecological conditions and cultivation
practices. Thymus vulgaris L. contains 12mL/kg of essential oil in it. The essen-
tial oil has both antioxidant and antimicrobial properties.
T. Iftikhar etal.
16.4.35 Monoterpenes andSesquiterpenes
Most of the terpenoids found in Thymus genus belong to monoterpenes group.
Monoterpenes constitute around 90% of thyme oil composition. Minute percentages of sequiterpenes are also present. In Thymus oils about 270 terpenes are
present. The phenolic terpenes i.e. thymol and carvacrol are of signicant importance. They constitute more than 10% of thyme oil composition. In plant kingdom
thymol and carvacrol rarely exists. Thus genus Thymus is the most common
source of these monoterpenoid phenols. This limited occurrence of these phenols
is the major cause of interest in thyme. Another compound linalool ranks third in
importance for the genus Thymus. It differs from other phenols in its ne sweet
smell. Phenylpropanoids constitutes around 7.8% of thyme essential oil. Two
compounds isoeugenol and cinnamol are signicant phenylpropanoids found in
genus Thymus.
16.4.36 Antioxidants
Flavonoid phenolic antioxidants are also present in abundance in thyme. Lutein,
luteolin, thrombin and zeaxanthin are some of the avonoids present in thyme
plants. All these compounds play, important roles in the human body. Like zeaxanthin helps in building yellow pigment that protects the eye from the effects of
harmful light sources. Lutein prevents cataracts and vision loss in adults. All
these show the nutritional importance of Thyme.
16.4.37 Antioxidant Properties ofThymus vulgaris L.
Compounds that prevent the oxidation of other compounds are known as antioxidants. In oxidation, electrons are transferred from a compound to an oxidizing
agent. As a result, free radicals are produced. If this chain reaction takes place
within the cell it will cause cell death. Antioxidants keep the cell safe by stopping
these chain reactions. They remove free radicals and intermediates from the cell and
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stop the oxidation reactions. Thycarvacrol and its oil is used in food for aroma and
avor. They are also used for the preservation of food. Since early times thyme
leaves are used in folk medicines. Thyme oil contains the per gram concentration as
arvarcrol (45 mg), Thymol (24.7 mg), β-Phellandrene (9.7 mg), essential oil
(4.1mg), Humuline (3.1mg), α-Phellandrene (2.3mg) and Myrcene (2.1mg) [32].
This composition of the oil was studied in research conducted to study anti-oxidant
properties of thyme oil. These compounds were not only the part of Thymus vul-
garis L. oil but also determined how effective it is in controlling aatoxin induce
oxidative stress in rats. Aatoxins disturb the rapid composition of blood, reduce
situations activity, with increase the amount of urea and nitric acid in blood together
with bringing changes in tissues of the liver. Results showed that a high dose of oil
can prevent such situations [33].
Globally, Thymus vulgaris L. and other species of thyme are used for its remark-
able benets in medicinal and non-medicinal aspects. With time great development
has been witnessed in uses of thyme hence transitioning it from a traditional herb to
serious drug in phytotherapy. Numerous researches have explored the pharmacological activities of essential oil and natural extract of thyme. Essential oil of thyme
possess antibacterial, antiviral, anticarcinogenic, antifungal, insecticidal and spasmolytical properties. The non-medicinal usage of thyme is also equally important
because it is used in cosmetics, food and aroma industries. Moreover, raw material
of thyme is also used in perfumery. Both the pharmacological and nonpharmacological uses of thyme and its essential oil are discussed in the successive
paragraphs.
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16.5 Importance ofThyme
16.5.1 Pharmaceutical Importance ofThymus vulgaris L.
Since early times, the Thymus vulgaris L. is being used for treating diseases such as
respiratory diseases like asthma, bronchitis and whooping cough. It is being administered to patients in form of tea, syrup, ointment or by inhaling its steam.
Atherosclerosis, toothache, infection of the urinary tract and dyspepsia could be
cured via Thymus vulgaris L.It also has antifungal properties. It eliminates fungal
infections from the stomach and intestine. Thymol, a component of the Thymus can
kill bacteria and parasites present in the stomach or intestine, thereby increasing the
appetite. Both Thymus plant extract and essential oil are reported to have pharmacological activities. Now Thyme is being used in drug rational phototherapy. Being an
incredible source of several nutrients, it maintains blood ow and has a great impact
on the overall system of the body [34].
Thymus vulgaris L. is also used in treating mental weakness. It has also been
proven effective in insomnia treatment. These remedial properties of the Thymus are
due to the presence of compounds i.e., avonoids, phenols, eugenols and most
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importantly thymol. Antispasmodic, bactericidal, anthelmintic are other properties
of Thymus species. Among all Thymus species, Thymus vulgaris L. is mostly cultivated in rural areas owing to its medicinal properties. It is used to treat inammatory
diseases, swelling by insect bites, muscle swelling and pain. The reason for its high
usage is the presence of a large amount of essential oil than any other species of the
Thymus genus. It also contains a high percentage of thymol because of its expectorant effects. However, Thymus vulgaris L. is expensive, therefore industries prefer
using other species [35]. Tablets named naturactive made from thyme are available
in markets for improvement in respiratory disorders.
Thymus essential oil contains thymol that is active against various infections.
The disinfectant properties of the Thymus make it effective for treating chronic fungal infections and chest issues such as bronchitis, asthma and whooping cough. Oil
of thyme is also used as a disinfectant in mouth wash due to its antibacterial and
antifungal properties. Chewing Thymus vulgaris L. leaves relieves throat infections.
Thymol is used in chest infection syrups. Moreover, its leaves extract is used to treat
worms in children. Infestations and infections caused by hookworms, ascarids,
Candida albicans, fungi, gram +ve and gram -ve bacteria are also treated using
Thyme extract and essential oil [36]. Thymol also improves liver functioning. In
villages, urinary infections are also being treated by using Thyme extracts. Laryngitis
can also be treated using plant extracts of Thymus vulgaris L.Thymol is also found
to be effective against enterobacteria infections. It is also reported for resolving
dermal issues such as dermatitis and bug bites. Massaging thyme oil can cure sciatica. Thymus serpyllum is found to show anti-thyrotropic effects in rats. They have
been reported for reduction of thyroid hormone in rats. However, in humans, such
results haven’t been reported yet. Thyme is also used since ancient times for curing
chest infection and congestion. Fresh leaves are the best remedy for treating sore
throat. Before production modern antibiotics medical bandages were used. To treat
liver and urinary infections, Thymus leaves are also used. The problem of oily skin
and acne can also be cured using thyme oil. In worship places it has also been used
as a fumigant. In pharmaceutical medicines, Thymus vulgaris L. is used mostly
because it contains the highest concentration of thymol which shows high antitussive and expectorant effects. Because Thymus vulgaris L. is expensive thereby other
species of Thymus are used in pharmaceutical companies. Due to its diverse properties, the essential oils of the Thymus have been studied in detail for use in various
industries [37].
Thymus vulgaris L. also has anti-cancerous properties. It has been proved to be
effective against breast carcinoma. It was found controlling cancer proliferation in
the colorectal HCT116 cancer cell model. It has also shown tumor inhibitory effects
in human leukemia. T. vulgaris has been observed to impede the growth of human
oral cavity carcinoma [38]. Research showed that essential oil inhibits the growth of
several tumor cells depending upon the concentration of oil. Thyme oil is also found
to be effective to control parasitic mites and honeybees. As compared to lavender
and laurel oil, Thymus vulgaris L. has the lowest LC
for Varroa destructor, a para-
50
sitic mite [26]. Thymus vulgaris L. oil is also found to be effective in the reduction
of laying eggs consequently resulting in a 10% mortality when used at 1%
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concentration. Red Thyme contains 54% thymol that was found to be effective
against Dermatophagoides farina (dust mite) [39].
Research has been carried out to determine the biological activities and chemical
makeup of T. vulgaris L.The activity of thyme oil against bacteria was evaluated
against nine cultures of gram -ve bacteria and six cultures of gram +ve bacteria [6].
Antibacterial activity was being evaluated by using bio impedance methodology,
keeping detection time as an evaluation parameter. The inhibitory effect was studied
via the plate counting technique. All the thyme essential oils showed antibacterial
activity against tested microorganisms. However, maximum activity was seen
against gram +ve cultures.
The essential oil obtained from thyme full ower showed principal effectiveness
against microorganisms. Only a few species retained 50% metabolic activity while
most of the cultures have been incapacitated entirely [40].The chemical constituents
of essential oils play a pivotal role in determining the antimicrobial activity of
essential oils [41]. The activity of thyme against microbes is linked to the thymol
and terepene hydrocarbons’ presence in the essential oil. P-Cymene when present
alone does not exhibit antimicrobial activity whereas when present along with thymol and terpene, it is found to have antimicrobial efcacy. Research has also shown
that not only the major constituents but also the minor components of essential oil
also show stronger antimicrobial efcacy which shows synergistic effects. Thymol
present in thyme oil has been found effective against microbes.
Research has been conducted to determine the antiviral activity of aqueous
extracts of the Lamiaceae family against the Herpes simplex virus. Extracts of
Thymus vulgaris L. showed inhibitory activity against Herpes simplex virus type 1
and 2 were tested invitro on RC-37 cells in a plaque reduction assay.
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16.5.2 Usage inTraditional Medicines
Since Romans and Greeks thyme has been cultivated and used for various purposes.
It was considered as an indispensable plant. Still it is believed that consuming one
cup of thyme extract provides freshness, lightness in the stomach and protects one
against the morning cough. Externally, thyme infusions and essential oil has been
used in folk medicines for treatment of injuries, bruises and ulcers [42]. It is believed
that thyme bath has sedative properties. Massaging thyme oil is used to treat sciatica
and arthritis. It also improves oxygenation. In traditional medicines thyme was used
for treating baldness. It also improves blood circulation within capillaries thus preventing seborrhhoea. Moreover, it possess ability to cure ulcers and various types of
dermatitis, injuries and bruises. It is also used in medicines for treatment of sleeping
disorders like insomnia. Gastro-intestinal troubles like dyspepsia, gastritis, diarrhea
and gastric ulcers can also be treated by using thyme oil.
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16.5.3 Thyme Usage inHomeopathy
Homeopathy was introduced by German doctor Samuel Hahnemann. The underlying principle of this therapy is the internal regulation of human body by a special
drug, who has different reactivity corresponding to each individual. It is also known
as “Simile principle”. This principle means that similar can be cured by something
similar. Till date, different plants and their part have been used for this purpose.
T. vulgaris L. and T. serpyllum L. for a long time have been used in homeopathy
[43]. However, in 1989 this usage had been stopped due to negative monographs.
16.5.4 Thyme Oil asAntispasmodic Agent
Thyme oil has found to have antispasmodic activity on intestinal smooth muscles
that have been contracted by various agents. It was observed to have antispasmodic
activity against all the agents causing contractions [44]. Thymol and carvacrol both
acts as antispasmodic agents.
16.6 Commercial Importance
16.6.1 Used inMouth Wash
Boiling 5gm dried Thymus vulgaris L. leaves in 100mL distilled water for 10min
and then straining (5% infusion). This remedy is effective for periodontal prophylaxis. Listerine, a mouthwash, contains thymol which is effective in reducing oral
bacteria [45].
16.6.2 Oils andHair Tonics
Thyme oil is also used in hair tonics and oils. 2 to 3 drops of a combination of
thyme, lavender, and cedarwood essential oil added to grapeseed and jojoba oil,
when massaged into the scalp for 7months cures alopecia areata. Paronychia can
be treated by adding 1 drop of thymol to chloroform and applying it to chronically
affected areas 3 times a day can cure it [46]. Diluted Thyme oil is also being used in
many ointments for curing skin diseases.
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