Essential oil chemical diversity of Iranian mints

Mentha is an important aromatic plant in the Lamiaceae family with a great industrial potential which has a very complex classification. Mint genotypes (Mentha x piperita 'Black', M. x piperita 'White', M. x aquatica, M. x villosa, M. longifolia, M. rutoundifolia, M. suaveolens) were gathered from different regions of Iran to investigate their essential oil (EO) yield and components. Mints were cultivated in the greenhouse and their essential oils were obtained by hydro distillation. EO yield varied from 0.51 to 1.3% (w / w). Gas chromatography analysis revealed that each species consisted of 46-64 constituents which make up about 98.2 %-99.85 % of their essential oils. A total 111 types of chemicals were identified, of which only ten were common between species, which together constitute 0.5 %-3.5 % of the total essential oils. The other 101 components showed a great diversity, of which 29 were major constituents of these genotypes. Principle component analysis (PCA) showed that the type and amount of the constituents are important to determine their groups. Diversity classification based on quantity and quality of EOs, put them into four groups. The highest detected components in the respective mints were: carvone (55.08 %), M. suaveolens; menthol (53.1 %), M. xpiperita 'Black'; pulegone (44.55 %), M. longifolia; menthofuran (38.67 %), M.xaquatica; menthol (32.36 %), M. x piperita L. 'White'; carvone (27.12 %), M. rutoundifolia; and neo-menthol (22.79 %), M.x villosa. For the first time new constituents were identified: alpha-terpinyl acetate (5.03 %) and geranyl tiglate (10.81 %) were found in M. longifolia; carvone (27.12 %) was identified in M. rutoundifolia; and neo-menthol (22.79 %) and pulegone (10.90 %) were detected in M. villosa. The phytochemicals demonstrate a great diversity among the studied Iranian mint species. These results merit further investigations at the gene expression and proteomics levels.

Automated summary

Mentha, an important aromatic plant in the Lamiaceae family, was studied for its essential oil yield and components in different regions of Iran. Gas chromatography analysis revealed the diverse composition of its essential oils, with each species consisting of 46-64 constituents. The study identified new constituents and highlighted the importance of understanding the genetic and proteomic levels of these mint species.