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)

Leopold Jirovetz,Gerhard Buchbauer,Evrich Schmidt,Margit Geissler,Ivan Murgov,Albena Stoyanova,Zapriana Denkova

doi:10.3797/scipharm.aut-05-03

Leopold Jirovetz, Gerhard Buchbauer + Show 5 more

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https://doi.org/10.3797/scipharm.aut-05-03

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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.

Highlights

In continuation of our research work on the field of combined data interpretation of antimicrobial testings and chiral phase gas chromatographic analysis of aroma samples, such as pure compounds, essential oils and extracts [I-61, the oxygenated monoterpenes 1,8-cineole, a-terpineol, terpinen-4-01 and camphor as well as the essential oils of pine (Pinus pinaster), rosemary (Rosmarinus officinalis, 2 samples) and tea tree (Melaleuca alternifolia), known to be rich in these aroma compounds [7-1I], were investigated
Pharmaceutical, perfumistic, cosmetic and food flavouring properties [7, 8-13] as well as the compositions [14-211 of essential oils of pine, rosemary and tea tree have been reported in many papers, detailed informations about the influence of the above cited single main compounds of these essential oils on their antimicrobial activities are not available until now
The obtained antimicrobial data (IZ=inhibition zones and minimum inhibitory concentration (MIC)=minimum inhibition concentrations) of this component were taken as references for further testings

Summary

Introduction

In continuation of our research work on the field of combined data interpretation of antimicrobial testings (agar diffusion and agar dilution methods) and chiral phase gas chromatographic (cyclodextrin) analysis of aroma samples, such as pure compounds, essential oils and extracts [I-61, the oxygenated monoterpenes 1,8-cineole, a-terpineol, terpinen-4-01 and camphor as well as the essential oils of pine (Pinus pinaster), rosemary (Rosmarinus officinalis, 2 samples) and tea tree (Melaleuca alternifolia), known to be rich in these aroma compounds [7-1I], were investigated. As result of the combined data interpretation the above mentioned influence of I,8-cineole, a-terpineol, terpinen-4-01 and camphor on the antimicrobial effects of essential oils of pine, rosemary and tea tree should be ascertained On basis of these data, a systematic investigation of aroma compounds and odorous samples (essential oils and extracts) will be continued in a running, international project

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