Assessing chemical diversity in essential oil compositions of Mint<i> (Mentha</i> spp.) cultivars and clones using Multivariate analysis

The morphological characteristics and chemical composition of plants are shaped by a combination of genetic factors and environmental influences. In particular, plants are continual pressure for variation due to environmental stresses and hybridization. The study aims to assess the chemodiversity among cultivars and clones of Mentha species cultivated under same climatic and soil conditions. The essential oil compositions of 83 samples, representing 11 different Mentha species, were analyzed with Gas Chromatography-Mass Spectrometry (GC-MS). Chemical profiles were classified using multivariate analysis techniques, including Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), and Mean Absolute Deviation (MAD). The results reveal that, despite inter-and intraspecific hybridization in Mentha species, similar chemotypes were observed across different species. Conversely, within the same species, chemotype diversity was present. Centroid clustering also demonstrated that closely related mint species tended to cluster together locally. The analysis identified 16 different chemical groups (chemotypes) among the 83 mint samples studied. Of these 83 samples, 31 were found to be rich in carvone, ranging from 36.4% to 77.7%. In addition to commercial chemotypes such as menthol and menthol/ menthone, rare chemotypes were identified, suggesting their potential significance for taxonomic classification. Additionally, the identification of chemotypes containing compounds with newly recognized physiological significance highlights the need to cultivate chemotypes rich in these compounds to meet the growing demands of the industry. Overall, this study sheds light on the chemodiversity within Mentha species and underscores the importance of understanding and harnessing this diversity for various applications.