Chemical Composition, Antimicrobial and Toxicological Evaluation of the Essential Oils of five Achillea species

This study presents chemical profiles, antimicrobial and toxicological evaluation of the essential oils (EOs) of five Achillea species native to the flora of Serbia (A. coarctata, A. chrysocoma, A. clypeolata, A. pseudopectinata and A. ageratifolia). The chemical compositions of the EOs were investigated by Gas Chromatography/Mass Spectrometry and Gas Chromatography/Flame Ionization Detector analyses. The microdilution method was used for antimicrobial and Artemia salina acute toxicity bioassay for toxicological evaluation of the EOs. Oxygenated monoterpenes have shown dominance in four out of five tested EOs (A. ageratifolia, A. pseudopectinata, A. chrysocoma and A. clypeolata) where 1,8-cineole and camphor were the most common dominant compounds. Conversely, A. coarctata EO was characterized by dominance of oxygenated sesquiterpenes with viridiflorol and cis-cadin-4-en-7-ol as the major compounds. Antimicrobial testing showed that studied EOs are characterized by broad-spectrum antimicrobial activity, which was not notably selective in relation to the Gram-staining properties of the tested microorganisms. Furthermore, all five EOs have shown high toxicity in A. salina lethality bioassay, suggesting that they may possess a certain level of pesticidal and/or antitumor properties. Achillea chrysocoma EO demonstrated the most prominent antimicrobial activity, but it was the fourth active in view of toxicity against A. salina. Contrary, A. coarctata EO was the most potent toxic agent toward A. salina, but it was only the fourth of the five regarding the antimicrobial potential. Presented results confirmed that highly toxic EOs could demonstrate moderate activity against the pathogenic microorganisms as the effects of the EOs diverge in pro- and eukaryotic cells.