Review of the Essential Oil Composition of Iranian Lamiaceae+

The immense Iranian plateau, which covers an area of 164,800 sq km of the Earth’s surface, is the habitat of innumerable plant species, owing to a great variety in climate and soil (Figure I). In Iran, there are 167 families of vascular plants, including 1,215 genera. The species, subspecies, varieties, and hybrids found thus far in Iran amount to 7,576 (almost 6,417 species, 611 subspecies, 465 varieties, and 83 hybrids), 2,100 taxa of which are endemic (1, 2). One of the most important families of Iranian flora is Lamiaceae Lindl. (Labiatae Juss.). The plant family consists of about 221 genera and 5,600 species comprised of aromatic, annual or perennial herbs, sub-shrubs, or shrubs. The leaves are opposite, sometimes whorled or even spirally arranged, and simple rarely pinnate. The flowers are bisexual, zygomorphic, usually have the floral formula K (5), C (5), A4, and G (2) and are arranged in verticillasters. The corolla is bilabiate and the stamens didynamous. With the exception of Rosmarinus, the genera have a gynobasic style and the four one-seeded nutlets have only a small surface of contact with one another. Moreover, the herbaceous members of the family have square stems. The leaves and other aerial parts may be pubescent and possess glandular trichomes, which contain the essential oil. Many members of the family are used as culinary or medicinal herbs, as a source of oils, and in some cases for the solution of oil constituents such as menthol and thymol; chemical races are common. In addition to the oil, constituents of the family include diterpenoids and triterpenoids, saponins, a few pyridine and pyrolidine alkaloids, insect-moulting hormones, polyphenols and tannins, iridoids and their glycosides, quinones, furanoids, cyclitols, coumarins and the sugars raffinose and stachyose (3). The Lamiaceae family in Iran has 47 genera; and 371 species, sub-species, and varieties (2). Moreover, it has one genus (Zhumeria), 137 species, 17 sub-species, 6 varieties and 6 hybrids which are endemic to the country (1). Genus Nepeta, with 69 species, is the largest genus of this family in Iran (2). This family has been extensively researched and in this chapter different studies on oils of Iranian species from the Lamiaceae family will be reviewed. The genera and species are presented in alphabetic order.