Pseudotsuga menziesii (Pinaceae): Volatile Profiles,Antimicrobial Activity and Toxicological Evaluation of Its Essential Oil

The present article investigates the chemical composition of volatiles of essential oil (EO) and headspace (HS) fraction, as well as biological activities of EO obtained from needles with twigs of Pseudotsuga menziesii var. menziesii cultivated in Serbia. The major class of compounds was monoterpene hydrocarbons with α-terpinolene, sabinene and β-pinene (EO), and sabinene, α-terpinolene and β-pinene (HS) as the dominant volatiles. Tested EO exhibited mostly low antimicrobial potential against investigated strains (ATCC and respiratory isolates), where MICs ranged 1.25–20.00 mg/mL. Nevertheless, based on presented results, where antimicrobial testing was done for the first time on human respiratory system isolates, there is a potential of this EO to be used as an adjuvant in the treatment of human respiratory infections, especially those caused by Pseudomonas aeruginosa or Candida albicans strains. Regarding toxicological evaluation, EO showed moderate toxicity in Artemia salina toxicity bioassay (LC₅₀=347.41, after 24 h) as well as week toxicity against Drosophila melanogaster with the ability only to moderately delay larval and pupal development.