Antimicrobial testinas and gas chromatoaraphic analvsis of pure oxvaenated monoterpenes 1.8-cineole, α-terpineol, terpinen-4-ol and camphor as well as target comoounds in essential oils of pine (Pinus pinaster), rosemary (Rosmarinus officinalis), tea tree (Melaleuca alternifolia)

Abstract

The oxygenated monoterpenes 1,8-cineole, α-terpineol, terpinen-4-ol and camphor as well as essential oils of pine, rosemary and tea tree, rich in these volatiles, were tested for their antimicrobial activities against some different strains of yeast, Gram-(-)- and Gram-(+)-bacteria by agar diffusion and agar dilution method, respectively. The same was done using the phenolic aroma compound eugenol as a reference-substance. The monoterpene alcohols a-terpineol and terpinen-4-ol were found to be active against all strains used in a wide range. The same result was obtained for the testings of essential oils of pine, rosemary (2 samples) and tea tree. Nearly all aroma chemicals and essential oils did show a significant high antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. For qualitative and quantitaive investigations of the key aroma compounds and the compositions of the essential oils, gas chromatographic methods (GC-FID and GCMS with columns of different polarities) were used and the results correlated with that of the antimicrobial testings. The obtained data are discussed to get more insight into the influence of pure aroma compounds on antimicrobial activities of essential oils.