The essential oils chemical composition of aerial parts of two accessions of Thymus atticus Čelak., growing wild in North Macedonia.

Thymus atticus Čelak. (Lamiaceae) is a Balkan species belonging to section Hyphodromi, subsect. Subbracteati. This study reports the first chemical characterisation of essential oils (EOs) from two T. atticus accessions (Ta1 and Ta2) growing wild in North Macedonia. EOs were obtained by hydrodistillation and analysed by GC-MS. Ta1 contained forty-nine compounds (95.33%), dominated by sesquiterpenes (69.29%), mainly (E)-nerolidol (30.83%) and β-caryophyllene (11.68%); Ta2 included forty-one metabolites (97.86%), with terpene hydrocarbons (81.97%) prevailing, chiefly β-caryophyllene (16.72%), myrcene (12.19%), and (E)-β-ocimene (10.97%). Multivariate analyses (PCA, HCA) revealed notable chemical variability, confirming the presence of distinct chemotypes within T. atticus. Ta1 matched the (E)-nerolidol/β-caryophyllene/germacrene D/myrcene chemotype, while Ta2 showed a unique profile, suggesting a potential new chemotype. These results expand knowledge of T. atticus chemical diversity and its potential taxonomic and phytochemical significance. A complete review of the essential oil compositions of Thymus belonging to the sect. Hyphodromi, subsect. Subbracteati has been carried out.