Essential Oil Composition of Achillea arabica Kotschy and Achillea teretifolia Willd from Three Different Microenvironments in Malatya, Türkiye

This study characterized the essential oil profiles of two Achillea species collected from Malatya Province, Türkiye, using hydrodistillation and analysis in two different laboratories with gas chromatography-mass spectrometry (GC-MS). Samples were collected from three distinct locations for each species, representing local microenvironments. In Laboratory-1 (non-polar column), the major compounds for A. arabica Kotschy were camphor (11.97%), eucalyptol (6.77%), borneol (6.17%), and trans-2,7-dimethyl-4,6-octadien-2-ol (5.53%), while for A. teretifolia Willd. were found to be eucalyptol (10.97%), piperitone (9.43%), camphor (6.13%), β -eudesmol (5.37%), and 4-terpineol (5.27%). In Laboratory 2 (polar column), major compounds for A. arabica were bisabolol oxide A (11.97%), palmitic acid (11.43%), α -bisabolone oxide A (6.2%), eucalyptol (5.73%), and camphor (5.4%) while for A. teretifolia Willd., eucalyptol (14.03%), camphor (12.07%), and piperitone (10.43%) were found. The findings demonstrated statistically significant differences (p < 0.05) between species, attributed to genetic and ecological factors rather than analytical errors, as confirmed by replicates showing consistent patterns despite inherent chromatographic variability. Z-score, heat map, PCA and PCA biplot analyses revealed significant chemotypic variations within species across narrow areas. These results highlight the role of geographical origin in chemotaxonomic differentiation and ecological adaptation of Achillea species, with implications for method standardization in essential oil studies.