Essential Oil – Ajowan

Botanical Information

Ajowan (Trachyspermum copticum) is an annual herb belonging to the Apiaceae (Umbelliferae) family. It is recognized by its small, greyish-brown seeds, which resemble parsley seeds in appearance. The plant is also known by several scientific synonyms, including T. ammi, Ammi copticum, Carum ajowan, C. copticum, and Ptychotis ajowan. Common names for the plant include ajuan and omum.

Distribution and Traditional Uses

Ajowan is primarily cultivated in India but is also grown in Afghanistan, Egypt, the West Indies, and the Seychelles. Traditionally, its seeds have been widely used as a culinary spice, particularly in curry powders, and as a household remedy for digestive disorders. In Indian traditional medicine, the seeds, tincture, essential oil, and its major active compound, thymol, have been used to treat various ailments, including cholera.

Essential Oil and Characteristics

Ajowan essential oil is extracted from the seeds by steam distillation. The oil is typically yellow-orange to reddish in colour and possesses a strong herbaceous, spicy, medicinal aroma similar to thyme. It is well known for its powerful antiseptic, germicidal, and carminative properties, making it effective in combating microorganisms and relieving digestive discomfort.

Chemical Composition

The major constituent of Ajowan essential oil is thymol. Other significant chemical components include pinene, cymene, dipentene, terpinene, and carvacrol, together with several other naturally occurring compounds that contribute to its therapeutic properties.

Safety and Precautions

Ajowan essential oil may cause irritation to the skin and mucous membranes. Due to its high thymol content, it should not be used during pregnancy. Furthermore, its overall toxicity has not been fully established; therefore, it is generally not recommended for aromatherapy or unsupervised home use.

Industrial Uses

Historically, Ajowan has been an important natural source of thymol for industrial applications. However, its use for thymol extraction has declined significantly because synthetic thymol is now more widely available and cost-effective.