Composition and Functionality of Nigella sativa Essential Oil

Nigella sativa L., whose seeds are known as black cumin, takes place in the Ranunculaceae family and has been grown in different regions of the world covering South Asian and East Mediterranean countries. It is an annual flowering plant and has an average 20–30 cm tall. As the fruit ripes, it forms a capsule containing small and black-colored seeds. Black cumin seeds contain protein, lipids, carbohydrates, crude fiber and ash. They have high lipid content and this quantity involves fixed and essential oil. The essential oil content of the seeds is about 0.4–1.2%. In order to extract the essential oil, different methods can be used such as hydrodistillation, microwave-assisted extraction, and supercritical carbon dioxide extraction. The extraction process may be achieved directly from crushed seeds or after separation of fixed oil. The main chemical constituents of black cumin essential oil are different types of terpene-derived hydrocarbons such as p-cymene, thymoquinone, thymol, α-thujene, α-pinene, β-pinene, carvacrol and γ-terpinene. Other minor constituents, like camphor, camphene, sabinene, longicyclene, α-phellandrene, borneol, carvone are also found. Thymoquinone is only found in black cumin essential oil and most important bioactive chemical compounds thanks to its wide application range for medical traits. The main usage areas of black cumin essential oil in the food industry are for the prevention of lipid oxidation and microbial growth. Due to these antioxidant and antimicrobial characteristics of the essential oil, it also plays a role as a functional food component. Increasing interest in functional foods makes it more popular. Leading nutraceutical features of black cumin essential oil as functional food has been reported in many studies and antibacterial, antioxidant, anti-inflammatory, anti-toxic, anticancer, anti-toxic, cardiovascular, analgesic, anticonvulsant, anti-ischemic, and immune system effects have been discussed. The preventive effect of the side impacts of chemotherapeutic agents has been also mentioned.