Agastache rugosa (baechohyang) is one of the most important aromatic plants native to the Republic of Korea. A. rugosa fragrance has been used to prepare incense since the Goryeo Dynasty in Korea. The present study aimed to explore the variation in the composition of essential oils from A. rugosa among native populations in Korea. The seeds of A. rugosa were collected from 90 different sites in Korea and seedlings were raised in the nursery. Essential oils were extracted from these populations by the steam distillation extraction method and their chemical compositions were analyzed by GC-MS. The yield of essential oils of A. rugosa ranged between 0.11% and 0.86%. A total of 204 components were identified from 90 populations of A. rugosa. Out of 204 components, 32 components were common in more than 40 individuals of A. rugosa and these 32 components were selected for principal component analysis (PCA). On the basis of the essential oil compositions, six chemotypes-estragole, pulegone, methyl eugenol, menthone, isopulegone, and nepetalactone-were distinguished according to their major components. As a result of the cluster analysis, 90 individuals of A. rugosa could be classified into three groups: estragole, methyl eugenol, and pulegone. A. rugosa exhibited significant chemical diversity among the individuals. The distribution of chemotypes is associated with the collection of seeds, suggesting that genetic diversity may influence the variations in the chemical compositions and concentrations within the species. This chemical diversity serves as the background to select cultivars for the cultivation and industrial applications of A. rugosa cultivars with high essential oil yield and concentration of its chemical components.
Keywords: Agastache rugose; baechohyang; chemotypes; essential oil; principal component analysis.