Phytochemical diversity within a plant population of Nepeta crassifolia species: A rich source of nepetalactone in Iran

Investigation of genetic diversity between and within populations is the first step in plant breeding programs. The present study focused on the phytochemical variation of essential oils of half-sib families within a plant population of Nepeta crassifolia species, collected from north of Tehran province, Iran. Air-dried aerial parts of several half-sib progenies were water distilled to extract their essential oils. Quantification and qualification of the essential oils constituents were carried out using gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC/MS). Dried plant materials, yielded from 0.09% to 0.73% (v/w) of essential oils. In half-sib families between 9 and 19 compounds were observed. In all of the studied families the extracted oils were predominated by oxygenated monoterpenes, and regarding the main phytochemical components, three chemotypes were recognized in the studied population. In most of the half-sib families, 4aα,7α,7aβ-nepetalactone isomer was dominant composition (38.7%–87.6%), while in two families 4aα,7α,7aα-nepetalactone isomer (41.6%) and 1,8-cineol (42.1%) were dominant constitutes. Significant correlation was not seen between biomass, essential oil yield and nepetalactone isomers. Comparing the presented results with essential oil components of other Nepeta species, such as N. cataria, revealed that N. crassifolia can be considered as a commercial source of nepetalactone isomers. Thus, promoting domestication and cultivation of N. crassifolia as industrial and medicinal species should be noticed.