Comparison of volatile profiles of Achillea sintenisii, an endemic species from Türkiye, and the evaluation of its essential oil's antibacterial and antibiofilm activities

Achillea sintenisii Hub-Mor is an endemic species in Türkiye, characterized by 1–10 capitula and ray flowers, and it thrives on calcareous rocks or gypsum-rich soils. This study aimed to determine the chemical composition and assess the antibacterial and antibiofilm activity of the essential oil of A. sintenisii (AS-EO). The essential oil compounds of the flowering aerial part of A. sintenisii were extracted using both hydrodistillation and solid-phase microextraction (SPME) techniques and identified by gas chromatography-mass spectrometry (GC-MS). Two different adsorbents were employed in the SPME approach. The yield of the essential oil of flowering aerial parts of A. sintenisii was 0,.4% h/h. A total of 74, 112, and 78 compounds were identified from the samples obtained by hydrodistillation (S1) and SPME extraction using the CAR-PDMS (S2) and PDMS-DVB (S3) adsorbents, respectively. The AS-EO exhibited the highest antibacterial activity against Staphylococcus aureus ATCC 25923 and S. aureus ATCC 43300 (MRSA), with a minimum inhibitory concentration (MIC) of <1/512 for each bacterium. This strong antibacterial effect may be attributed to the high content of 1,8-cineole and l-borneol. However, AS-EO did not exhibit any antibiofilm activity. These findings suggest that the essential oil of A. sintenisii has potential as a natural antibacterial agent, warranting further research to uncover its full potential.