Chemo-geographical variations in volatile profiles of Mentha longifolia (L.) populations from Iran

Mint (Mentha) has been used in traditional medicine for centuries and is a key species in the Lamiaceae family, with seven varieties found in the Iranian flora. Despite its extensive use in conventional medicine, limited research has focused on the detailed chemical profiling of this species in specific ecological contexts. This study investigates the essential oil composition of M. longifolia ecotypes naturally growing in the northwest region of Iran, highlighting the species' chemical diversity and its potential applications in pharmaceutical and agricultural industries. Using high-performance liquid chromatography (HPLC), 20 compounds were identified, accounting for 92.82 % to 100 % of the total oil composition. The main compounds were polegune (7.18-52.23 %), menthone (10.18-32.54 %) and piperitenone oxide (0.77-16.01 %). Additionally, oleanolic acid and ursolic acid, two isomeric triterpenes with recognized therapeutic potential, were quantified in the ecotype samples, with concentrations ranging from 0.17-8.07 mg/g and 0.24-2.94 mg/ g, respectively. At a 50 % similarity, the essential oil properties were classified into two sub-clusters: Cluster I, which mainly consisted of six ecotypes and Cluster II, which included two. Cluster analysis revealed two subgroups of ecotypes based on their essential oil profiles, suggesting environmental factors may influence the chemical composition. The findings underscore the significant variation in bioactive compounds among M. longifolia ecotypes and provide valuable insights for selecting and cultivating chemotypes with enhanced medicinal or aromatic properties. This study contributes to the growing body of knowledge on M. longifolia and supports its broader application in natural product development and sustainable agriculture.