Thyme

Scientific Name(s): Thymus vulgaris L. Family: Lamiaceae (Mint)

Common Name(s): Garden thyme , common thyme

Uses

Thyme has primarily culinary uses. Thyme extracts and thymol have been used in cough mixtures and mouthwashes, as well as for skin conditions, especially fungal infections. Clinical trials are lacking to support these uses.

Dosing

Studies are lacking to guide clinical dosages.

Contraindications

Information is lacking.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

None well documented.

Adverse Reactions

Contact dermatitis and systemic allergy have been reported.

Toxicology

Information is lacking.

Botany

There are 6 recognized Thymus species, but many hybrids and varieties exist. T. vulgaris is a perennial plant native to some European and Asian countries. Thyme is a woody perennial (evergreen in mild winters) and is primarily grown as a herb. Numerous woody stems grow upward to form the 0.3 m height of the plant. The highly aromatic leaves are tiny, elliptical, and grey-green in color, and the margins roll under (revolute). Tiny tubular lilac flowers appear in late spring. 1 , 2

History

Thyme was used as a symbol of elegance and grace in ancient Greece. Roman soldiers bathed in water infused with thyme for vigor, and Egyptians used thyme in the embalming process. Thyme sprigs were thought to be protective against plague, and thyme oil was used as an antiseptic during World War I. Teas made from thyme have been traditionally used for GI disorders and to treat intestinal parasites such as hookworm. Other traditional uses include treatment of bronchitis, as an agent in cough mixtures and mouthwashes, and as a topical application for acne and skin infections. Thyme has culinary applications and is commonly added to sausage meat and stuffing. It is used for its flavor in cosmetics and has been added to mouthwashes and toothpastes. 3 , 4

Chemistry

Although the essential oil of thyme has primarily been evaluated, 5 , 6 , 7 , 8 some studies report on individual constituents isolated from the leaves and aerial plant parts. 9 , 10 , 11 , 12 , 13 , 14 Composition varies with species, geographic distribution, and extraction methods.

Major chemical components include carvacrol and thymol, with cadalene, cineole, myrcene, terpinene, linalool, cymene, rosmarinic acid, and many other chemical constituents reported. Monoterpenoids, flavonoid glycosides, phenolic compounds, and polysaccharides have been identified by spectrophotometric analysis and thin-layer chromatography. 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14

Uses and Pharmacology

Clinical trials are lacking, with studies largely based on chemical elucidation and analysis and laboratory experimentation.

Antimicrobial effects

Extracts of thyme and its individual chemical constituents have shown activity against various human pathogenic bacteria and fungi in in vitro studies, and thymol is commonly used in mouthwash preparations with chlorhexidine. Gram-positive bacteria (including Pseudomonas aeruginosa , Escherichia coli , and Salmonella and Shigella species) appear more susceptible than gram-negative bacteria. 2 , 3 , 6

Fungicidal activity on Candida species, Aspergillus , and other fungi has been demonstrated by carvacrol, thymol, and p-cymene, as well as the essential oil of thyme. 3 , 8 , 15 Potentiation of amphotericin B against Candida albicans was demonstrated in one in vitro experiment. 15

Antioxidant effects

Extracts of thyme and individual chemical constituents have been evaluated for their antioxidant potential. Phenolic constituents demonstrated nitric oxide scavenging potential in one experiment, 16 with other tests showing effects on lipid peroxidation, free radical scavenging, hydrogen ion donation, and activity in oil stability index tests. 3 , 6 , 14 , 17

Other effects

Antiplatelet aggregating activity has been demonstrated in vitro by thymol and a biphenyl compound extracted from thyme. 18

Carvacrol, thymol, linool, and thymol derivatives thymoquinone and thymohydroquinone inhibited acetylcholinesterase in laboratory experiments. Because of the decrease in hydrolysis of acetylcholine, a role in Alzheimer disease has been suggested; however, clinical trials are lacking to support this use. 3 , 9

A relaxant effect of thyme extract has been demonstrated on guinea pig tracheal chains. The bronchodilatory effect is suggested to be comparable with theophylline. 19

Increases in glutathione-S-transferase (GST) enzyme and liver mass were observed in mice fed thyme extracts (2%) daily for 7 days, leading the investigators to postulate a detoxifying role for thyme because the conjugation of glutathione to various toxins would be enhanced. 20

Dosage

Studies are lacking to guide clinical applications. Tinctures and the essential oil are used topically for fungal infections. Thyme infusions have been used as a gargle at 5% concentrations. 2

The pharmacokinetics of thymol in healthy adults have been evaluated. No free thymol was found in the blood or urine, with sulfate and glucuronide metabolites identified in the urine. A mean terminal elimination half-life was estimated to be 10 hours. 21

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Thyme tea is reported to be used traditionally postpartum to induce uterine contractions and expulsion of the placenta; however, clinical or pharmacological data are lacking, and despite widespread use of thyme, safety problems have not been reported. 2

Interactions

Information is lacking. Increases in GST levels were observed in experiments in mice. 20

Adverse Reactions

Information is lacking. Contact dermatitis and systemic reactions to thyme have been reported. Cross-reactivity with rosemary is a common finding with skin patch testing. 4 , 22 , 23

Toxicology

Information is lacking. Murine macrophage cell viability was unaffected at low to intermediate concentrations (less than 50 mcg/mL) of thyme extract. 16 Mutagenic activity has not been found in a limited number of tests. 2

Bibliography

1. Thymus vulgaris L. USDA, NRCS. 2008. The PLANTS Database ( http://plants.usda.gov , March 2009). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
2. Herba Thymi. In: WHO Monographs on Selected Medicinal Plants . Vol 1. Geneva, Switzerland: World Health Organization; 1999: 259-266.
3. Figueiredo AC, Barroso JG, Pedro LG, Salgueiro L, Miguel MG, Faleiro ML. Portuguese Thymbra and Thymus species volatiles: chemical composition and biological activities. Curr Pharm Des . 2008;14(29):3120-3140.
4. Spiewak R, Skorska C, Dutkiewicz J. Occupational airborne contact dermatitis caused by thyme dust. Contact Dermatitis . 2001;44(4):235-239.
5. Kitajima J, Ishikawa T, Urabe A, Satoh M. Monoterpenoids and their glycosides from the leaf of thyme. Phytochemistry . 2004;65(24):3279-3287.
6. Bozin B, Mimica-Dukic N, Simin N, Anackov G. Characterization of the volatile composition of essential oils of some lamiaceae spices and the antimicrobial and antioxidant activities of the entire oils. J Agric Food Chem . 2006;54(5):1822-1828.
7. Diaz-Maroto MC, Diaz-Maroto Hidalgo IJ, Sanchez-Palomo E, Perez-Coello MS. Volatile components and key odorants of fennel ( Foeniculum vulgare Mill.) and thyme ( Thymus vulgaris L.) oil extracts obtained by simultaneous distillation-extraction and supercritical fluid extraction. J Agric Food Chem . 2005;53(13):5385-5389.
8. Pina-Vaz C, Gonçalves Rodrigues A, Pinto E, et al. Antifungal activity of Thymus oils and their major compounds. J Eur Acad Dermatol Venereol . 2004;18(1):73-78.
9. Jukic M, Politeo O, Maksimovic M, Milos M, Milos M. In vitro acetylcholinesterase inhibitory properties of thymol, carvacrol and their derivatives thymoquinone and thymohydroquinone. Phytother Res . 2007;21(3):259-261.
10. Kitajima J, Ishikawa T, Urabe A. A new hydroxyjasmone glucoside and its related compounds from the leaf of thyme. Chem Pharm Bull (Tokyo) . 2004;52(8):1013-1014.
11. Chun H, Shin DH, Hong BS, Cho HY, Yang HC. Purification and biological activity of acidic polysaccharide from leaves of Thymus vulgaris L. Biol Pharm Bull . 2001;24(8):941-946.
12. Chun H, Jun WJ, Shin DH, Hong BS, Cho HY, Yang HC. Purification and characterization of anti-complementary polysaccharide from leaves of Thymus vulgaris L. Chem Pharm Bull . 2001;49(6):762-764.
13. Takeuchi H, Lu ZG, Fujita T. New monoterpene glucoside from the aerial parts of thyme ( Thymus vulgaris L.). Biosci Biotechnol Biochem . 2004;68(5):1131-1134.
14. Dapkevicius A, van Beek TA, Lelyveld GP, et al. Isolation and structure elucidation of radical scavengers from Thymus vulgaris leaves. J Nat Prod . 2002;65(6):892-896.
15. Giordani R, Regli P, Kaloustian J, Mikaïl C, Abou L, Portugal H. Antifungal effect of various essential oils against Candida albicans . Potentiation of antifungal action of amphotericin B by essential oil from Thymus vulgaris . Phytother Res . 2004;18(12):990-995.
16. Vigo E, Cepeda A, Gualillo O, Perez-Fernandez R. In-vitro anti-inflammatory effect of Eucalyptus globulu s and Thymus vulgaris : nitric oxide inhibition in J774A.1 murine macrophages. J Pharm Pharmacol . 2004;56(2):257-263.
17. Miura K, Kikuzaki H, Nakatani N. Antioxidant activity of chemical components from sage ( Salvia officinalis L.) and thyme ( Thymus vulgaris L.) measured by the oil stability index method. J Agric Food Chem . 2002;50(7):1845-1851.
18. Okazaki K, Kawazoe K, Takaishi Y. Human platelet aggregation inhibitors from thyme ( Thymus vulgaris L.). Phytother Res . 2002;16(4):398-399.
19. Boskabady MH, Aslani MR, Kiani S. Relaxant effect of Thymus vulgaris on guinea-pig tracheal chains and its possible mechanism(s). Phytother Res . 2006;20(1):28-33.
20. Sasaki K, Wada K, Tanaka Y, Yoshimura T, Matuoka K, Anno T. Thyme ( Thymus vulgaris L.) leaves and its constituents increase the activities of xenobiotic-metabolizing enzymes in mouse liver. J Med Food . 2005;8(2):184-189.
21. Kohlert C, Schindler G, März RW, et al. Systemic availability and pharmacokinetics of thymol in humans. J Clin Pharmacol . 2002;42(7):731-737.
22. Martínez-González MC, Goday Buján JJ, Martínez Gómez W, Fonseca Capdevila E. Concomitant allergic contact dermatitis due to Rosmarinus officinalis (rosemary) and Thymus vulgaris (thyme). Contact Dermatitis . 2007;56(1):49-50.
23. Armisén M, Rodríguez V, Vidal C. Photoaggravated allergic contact dermatitis due to Rosmarinus officinalis cross-reactive with Thymus vulgaris . Contact Dermatitis . 2003;48(1):52-53.

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