MEDICINAL AND AROMATIC CROPS (2+1)

Importance and chemical composition

Thyme (Thymus vulgaris Linn) commonly called ‘Common Thyme’ of ‘Garden Thyme’, belonging to the family Lamiaceae, is an important herb used by man since ancient times On distillation, the herb yields the Red Thyme oil of commerce. Apart from the oil the other constituents of thyme are tritepinoid saponins, flavones, ursolic acid (1.5% in the tops), coffeic acid, bitter principle, tannins and resins. Besides, there are several other wild species which yield volatile oil. They are T.serpyllum L., T. zygus L. and T.satureioides Coss and Bal. Thymol. Linalool and linalyl acetate are the major compounds present in T.zygus and T.serpyllum, T.zygus and its var. gracitis are also a source for genuine thyme oil, while thymol, burneol and α-terpineol are the major compounds in T.satureioides. The oil called the ‘oil of thyme’ in commerce is a colourless, yellow or red liquid with a characteristic pleasant odour, and a pungent taste. The composition and also the quality of the oil are reported to vary in different geographical areas. The concentration of the active principle (Thymol) is high (60%) in the Spanish oil and is low (20-35%) in the French and Moroccan oils, whereas, carvacrol is present in minor amounts. The seeds yield 37% of a drying oil which contains mainly linolenic, lindeic and oleic acids.

The leaves and flowers find use as food flavourants and seasoning for various food items, especially fish and meat preparations and for garnishing. Medicinally, the leaves are said to possess laxative, stomachic and tonic properties, good for the kidney and eye and are blood purifiers. The herb also has insect-repellent property. It is used in perfumery and in liquor distillery as well. The dried leaves and floral tops constituting the thyme of commerce are known as Thymi Herba in pharmacy and contain not more than 3% of stems over 1 mm in diameter and 2% of other organic matter and yields 4% acid insoluble ash. The shoot-extracts of flowering thyme plants have antibacterial action against Micrococcus pyogenes var. aureus and Escherichia coli. The herb which has a pun get taste is reported to possess antiseptic, antihelmentic, expectorant, carminative, diuretic, alexiteric, emmenagogue and sedative properties.

Thyme oil has antiseptic, antispasmodic and carminative properties. It is used in mouthwashes and gargles. Formulations containing thyme oil are available for the treatment of whooping cough and bronchitis, the oil is used in soaps, perfumes and for flavouring food products such as a meat, sausages, sauces and canned food.