Quantitative and qualitative study of essential oil in some accessions of Nepeta spp. and determination of essential oil components capability in intra and inter-specific relationships analysis

Nepeta is one of the largest genera of the Lamiaceae family, and Iran is one of the main centers of origin of the genus. There are lots of reports related to biological activities of secondary metabolites of Nepeta that shows the importance of the genus. Quantity and quality of essential oil (EO) components of 12 accessions of three Iranian Nepeta species, N. cataria, N. menthoides and N. crassifolia, cultivated in West of Tehran, were studied.Also, EO components capability on intra and inter-specific relationships was investigated. Plant aerial parts were harvested at full bloom stage. EO was extracted by hydrodistillation method from shade-dried plant materials. EO was quantitatively and qualitatively analyzed by GC and GC/MS, respectively.Principal component analysis was used in order to determine the role of each EO components in intra and inter-specific diversity. The most part of EO yield (w/w) belonged to “Markazi” accession of N. cataria (2.5%). Main EO component(s) of species were NepII (4aα,7α,7aβ-nepetalactone) in N. cataria, 1,8-cineole and NepII in N. menthoides and NepI (4aα,7α,7aα-nepetalactone), 1,8-cineole and NepII in N. crassifolia. N. crassifolia and N. cataria species, respectively, allocated on the first positions based on the quantity of NepI and II. N. cataria had the most total quantity of nepetalactone (97.8-99.1%). Results indicated that EO components were able to distinguish species, and to identify intra and inter-specific relationships. N. crassifolia and N. cataria species were separated from N. menthoides by cluster and PCA analysis based on EO components.