Morphological and Chemical Diversity of Thymus Daenensis Celak (Lamiaceae) in Iran

Traditional medicine has maintained its importance in the world, and its use is rapidly gaining in popularity in industrialized countries. To cure illnesses and ailments almost 80% of the global population use traditional medicine, mainly medicinal plants. Today, according to the World Health Organization, 20,000 medicinal and aromatic plants are used in the world [1]. Long term experience has shown that the local populations of the flowering plants are highly variable. This diversity includes the morphological properties and hidden differences such as chromosomes, allozyme, natural products and etc. [2]. The diversity can be detected in a gradual diversification forms as well as a mosaic of ecotypes [3]. The thyme genus shows the morphological and chemical polymorphism from subfamily Nepetoidae in Lamiaceae family [4]. Many species of thyme have phenolic terpenes that content over 10% of thymol and carvacrol. However, there are many species of thyme that the compounds are absent or less than 10% and therefore the Thymus species is divided into two phenolic and non-phenolic types based on these combinations. P-Cymene and γ-Terpinene are the second groups of important compounds in thyme genus. Other hydrocarbon compounds of the thyme’s essential oils by values of more than 10% as follows: Linalool, Geraniol, 1,8 –Cineole tried out chemical diversity of 71 Spain’s populations of wild thyme from different climatic regions and proclaimed that pure and hybrid populations were completely separated by morphometric and anatomical assessment [5]. Hartvig conducted a research on the population complex of Thymus teucrioides Boiss. et spruner and recognized three new taxa [6]. Hadj Ali evaluated essential oils and genetic diversity of eight natural populations of Thymus algeriensis Boiss. et Reut and concluded that the chemical and genetic diversity of populations is accordance with geographical distances of isolated populations, although, the chemical diversity of the populations was more than variety of RAPDs molecular markers [7]. Babalar affirmed that planting different populations in the same conditions diminish environmental effects in the development of growth characteristics, consequently variety and amount of ingredients and the genetic variation of ecotypes were clearly revealed. They evaluated the morphological diversity and essential oils yields of ten populations of thyme and concluded that were belonged to four groups. They observed significant differences between the different characteristics [8]. According to Jakko Jalas Classification, Thymus daenensis Celak. Belongs to the subsection Kotschyani, from the section Serpyllum in thymus Genus [9].