Thyme

Although thyme has been used as a cooking spice for centuries in Europe, it is also used medicinally to treat common infections, coughs, bronchitis and asthma. The 17th century herbalist Nicholas Culpeper recommended thyme for whooping cough, gout, stomach pains and shortness of breath. It was also used in perfumes and embalming oils. In medieval times the plant was seen as imparting courage and vigour (Blumenthal et al 2000).

OTHER NAMES:

Common thyme, garden thyme, farigola, folia thymi, gartenthymian, herba thymi, almindelig timian, thym, thymian, thymianblätter, timo

BOTANICAL NAME/FAMILY:

Thymus vulgaris (family Lamiaceae or Labiatae)

PLANT PARTS USED:

Leaves and flowering tops

CHEMICAL COMPONENTS:

The primary constituents are the volatile oils (1–2.5%), which include phenols (0.5%), namely thymol (30–70%), eugenol, and carvacrol (3–15%), also flavonoids, apigenin, luteolin and saponins and tannins. Rosmarinic acid, caffeic acid and calcium are also found in significant quantities (Duke 2003). The herb also contains bitter principles and salicylates.

MAIN ACTIONS:

Although thyme has not been significantly investigated in human studies, there has been some investigation into the activity of thymol and the volatile oil component of the herb. It is not known whether results obtained for these constituents are representative for the crude herb, but they provide some further understanding. Both the essential oil and thymol are ingredients in many proprietary products.

ANTITUSSIVE AND ANTISPASMODIC EFFECTS

These actions have been attributed to the phenolic compounds in thyme (WHO 2003). Antispasmodic effects on trachea and guinea pig ileum have been demonstrated for these constituents. The saponin content is believed to have expectorant activity, as demonstrated in animal studies.

ANTIMICROBIAL

In vitro tests have demonstrated activity against Escherichia coli, Listeria monocytogenes and Salmonella enterica for thyme extract (Friedman et al 2002). A review of the antibacterial and antifungal properties of the essential oil of thyme in vitro has demonstrated effectiveness against a wide range of pathogens including Clostridium botulinum, E. coli, Haemophilus influenzae, Klebsiella pneumoniae, Salmonella typhi, Staphylococcus aureus and Candida albicans (Kalemba & Kunicka 2003).

Effects are most likely due to the eugenol, thymol and carvacrol constituents. Aqueous thyme extract also exhibited a significant inhibitory effect on Helicobacter pylori, reducing both its growth and its potent urease activity in vitro (Tabak et al 1996).

Thymol and eugenol have demonstrated antifungal activity by establishing the ability to alter the cell wall and membrane of the yeast Saccharomyces cervisiae (Bennis et al 2004).

ANTIOXIDANT

Eugenol, carvacrol, thymol and 4-allylphenol (5 ìg/mL) all inhibited the oxidation of hexanal for a period of 30 days, demonstrating potent antioxidant activity comparable to alpha-tocopherol (Lee et al 2005).

ASTRINGENT

The tannin content of the herb is chiefly responsible for its astringent activity.

ANTHELMINTIC

Thymol possesses anthelmintic activity, demonstrated in vitro (Newell et al 1996).

OTHER ACTIONS

Anti-inflammatory due to thymol and carvacrol.

CLINICAL USE:

Thyme has not been significantly investigated in controlled studies, therefore information is generally derived from evidence of activity and traditional use and the clinical significance is unknown.

RESPIRATORY TRACT INFECTIONS

Thyme extract has been used to treat the common cold, bronchitis, laryngitis and tonsillitis. It is orally ingested or used in a gargle for local activity, based on the herb’s suspected antimicrobial and antitussive activities.

Bronchitis

Encouraging data have been reported for chronic bronchitis treated by thyme in combination with other herbs in large (n > 3000) comparative clinical trials, although no data are available for thyme as a stand-alone treatment (Ernst et al 1997). Thyme is approved by Commission E in the treatment of bronchitis, whooping cough and upper respiratory tract catarrh (Blumenthal et al 2000).

DIARRHEA

The astringent activity of thyme provides a theoretical basis for its application in this condition.

GASTRITIS AND DYSPEPSIA

The bitter principles present in the herb and its antispasmodic activity provide a theoretical basis for its use in these conditions. SKIN DISINFECTION (TOPICAL USE) Thyme extract has been used topically for infection control in minor wounds. The herb’s antimicrobial and astringent activity provides a theoretical basis for this use.

OTHER USES:

Traditionally, it has been used to aid in labor and delivery, promote menstruation and topically for warts and inflamed swellings (Fisher & Painter 1996). It has also been used to treat enuresis in children.

DOSAGE RANGE:

INTERNAL USE
· Fluid extract (1:1): 1–2 mL up to three times daily.
· Fluid extract (1:2): 15–40 mL/week.
· Tincture (1:5): 2–6 mL three times daily.
· Infusion of dried herb: 1–4 g three times daily.
EXTERNAL USE
· 5% infusion used as a compress.

ADVERSE REACTIONS:

The volatile oil is considered an irritant topically and can cause nausea and vomiting, headache, dizziness, convulsions, cardiac or respiratory arrest if taken internally (Newell et al 1996). As such, the crude herb is considered far safer. Contact dermatitis reactions have been reported with topical use (Lorenzi et al 1995).

SIGNIFICANT INTERACTIONS:

Thyme may induce enzymes in phase one and two detoxification in the liver (Sasaki et al 2005). The clinical significance of this is unknown.

CONTRAINDICATIONS AND PRECAUTIONS:

Contraindicated in people who are allergic to the Labiatae family of plants. Other cautions are gastritis, enterocolitis and congestive heart failure (Ernst et al 2001).

PREGNANCY USE:

Essential oil not recommended in pregnancy.

PRACTICE POINTS/PATIENT COUNSELLING:

· Although thyme is used as a cooking spice, it is also used medicinally to treat common upper respiratory tract infections, coughs, bronchitis and asthma, dyspepsia and diarrhoea.

· Thyme extract is used as a gargle for pharyngitis or applied topically (5% dilution) as a compress to wounds due to its antimicrobial and astringent activities.

· Thyme has not been significantly investigated in controlled trials, so much information is based on traditional use or evidence of activity.

· Thyme has antispasmodic, antimicrobial, antitussive, astringent and anthelmintic activities as demonstrated in vitro or in animal studies.

ANSWERS TO PATIENTS’ FREQUENTLY ASKED QUESTIONS:

What will this herb do for me?

When taken internally, thyme is used to treat bronchitis, symptoms of the common cold, diarrhoea and dyspepsia. It is also used as an antiseptic gargle for sore throats and can be diluted and applied externally to minor wounds.

When will it start to work?

The lack of human studies for this herb make it difficult to determine when effects will start to occur.

Are there any safety issues?

Thyme should not be used by people allergic to the Labiatae family of plants or in pregnancy, and used cautiously in gastritis, enterocolitis and congestive heart failure.

SOURCES

REFERENCES:

Bennis S et al. Surface alteration of Saccharomyces cerevisiae induced by thymol and eugenol. Lett Appl Microbiol 38.6 (2004): 454-8. Blumenthal M, Goldberg A, Brinckmann J (eds). Herbal Medicine: Expanded Commission E Monographs. Austin, TX: Integrative Medicine Communications, 2000. Duke JA. Dr Duke’s Phytochemical and Ethnobotanical Databases. US Department of Agriculture–Agricultural Research Service–National Germplasm Resources Laboratory. Beltsville Agricultural Research Center, Beltsville, MD. www.ars-grin.gov/duke (accessed 09-06-2003). Ernst E et al. The Desktop Guide to Complementary and Alternative Medicine: An Evidence-based Approach. St Louis: Mosby, 2001. Ernst E et al. Acute bronchitis: effectiveness of Sinupret. Comparative study with common expectorants in 3,187 patients. Fortschr Med 115.11 (1997): 52-3. Fisher C, Painter G. Materia Medica for the Southern Hemisphere. Auckland: Fisher-Painter Publishers, 1996. Friedman M, Henika PR, Mandrell RE. Bactericidal activities of plant essential oils and some of their isolated constituents against Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, and Salmonella enterica. J Food Prot 65.10 (2002): 1545-60. Kalemba D, Kunicka A. Antibacterial and antifungal properties of essential oils. Curr Med Chem 10.10 (2003): 813-29. Lee S et al. Identification of volatile components in basil (Ocimum basilicum L.) and thyme leaves (Thymus vulgaris L.) and their antioxidant properties. Food Chem 91 (2005): 131-7. Lorenzi S et al. Allergic contact dermatitis due to thymol. Contact Dermatitis 33.6 (1995): 439-40. Newell CA, Anderson LA, Phillipson JD. Herbal Medicines: A Guide for Health Care Professionals. London: The Pharmaceutical Press, 1996. Sasaki K et al. Thyme (Thymus vulgaris L.) leaves and its constituents increase the activities of xenobioticmetabolizing enzymes in mouse liver. J Med Food 8.2 (2005): 184-9. Tabak M et al. In vitro inhibition of Helicobacter pylori by extracts of thyme. J Appl Bacteriol 80.6 (1996): 667- 72. World Health Organization Department of Essential Drugs and Medicines Policy (EDM). Essential drugs and medicines policy: Herba Thymi. Geneva: WHO, 2003; 259-66.

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