Botanical Name / Family
Thymus vulgaris (family Lamiaceae or Labiatae)
Plant Parts Used
Leaves and flowering tops
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. The herb also contains bitter principles and salicylates.
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.
Thyme: 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.
In vitro tests have demonstrated activity against Escherichia coli, Listeria monocytogenes and Salmonella enterica for thyme extract. 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. 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.
Thymol and eugenol have demonstrated antifungal activity by establishing the ability to alter the cell wall and membrane of the yeast Saccharomyces cervisiae.
Eugenol, carvacrol, thymol and 4-allylphenol (5 µg/mL) all inhibited the oxidation of hexanal for a period of 30 days, demonstrating potent antioxidant activity comparable to alpha-tocopherol.
The tannin content of the herb is chiefly responsible for its astringent activity.
Thymol possesses anthelmintic activity, demonstrated in vitro.
Thyme: Other Actions
Anti-inflammatory due to thymol and carvacrol.