Relationship between bioactivity and chemical composition of commercial essential oils

In order to establish the value of the use of biological activities as accessory criteria (in conjunction with gas chromatography, but in the absence of enantiomeric analysis) for establishing the authenticity of essential oils, the biological activities of 105 commercial essential oils were investigated against 25 species of bacteria, 20 strains of Listeria monocytogenes, and three filamentous fungi; their antioxidant action was also determined and all the results were related to the actual chemical composition of the oils as determined by gas chromatography. The results showed some relationship between the major components and some bioactivities. There was a negative correlation between 1,8-cineole content and antifungal activity. There was, however, great variability between the biological action of different samples of individual oils and groups of oils under the same general name, e.g. lavender, eucalyptus or chamomile, which was reflected in differences in chemical composition, The results suggest that, although the biological activities are not all related to the main components, any significant blending, rectification and adulteration of commercial oils can be monitored by their biological activities. The use of essential oils named simply as ‘chamomile’ or ‘eucalyptus’, or any commercial oil which has been adulterated, cannot be justifiably used in treating medical conditions unless it can be shown that the action is non-specific and independent of the chemical composition. © 1998 John Wiley & Sons, Ltd.