Z Lebensm Unters Forsch (1993) 197:20-23 Original paper Composition and antioxidant activity of essential oils from Oregano plants grown wild in Greece Vasiliki Lagouri 1, George Blekas 1, Maria Tsimidou 1, Stella Kokkini 2, Dimitrios Boskou 1 1 Laboratory of Food Chemistry and Technology, Faculty of Chemistry, Aristotle University of Thessaloniki, GR-54006 Thessaloniki, Greece 2 Laboratory of Systematic Botany and Phytogeography, Faculty of Biology, Aristotle University of Thessaloniki, GR-54006 Thessaloniki, Greece Received December 17, 1992 Zeitschrift fQr Springer-Verlag 1993 Zusammensetzung und antioxidative Aktivit~it etherischer Ole von Oregano-Pflanzen aus Griechenland Zusammenfassung. Bei dieser Arbeit wurden vier Proben etherischer 01e aus Pflanzen gewonnen, die weit verbrei- tet in Griechenland sind und von 6konomischer Wichtig- keit in der ganzen Welt am Gewiirzmarkt sind. Es wur- den Carvacrol und Thymol auf ihre wahrscheinliche anti- oxidative Aktivit~it getestet. Die vier Pflanzenarten sind Origanum vulgare hirtum, Origanum onites, Coridothymus eapitatus und Satureja thymbra. Die etherischen Ole wur- den mit Hilfe der Gaschromatographie-Massenspektro- skopie charakterisiert. Sowohl die untersuchten etheri- schen Ole als auch Carvacrol und Thymol wurden durch TLC und auch durch Messung der Peroxid-Werte eines bei 35 ~ aufbewahrten Schweinefettes getestet. Die Er- gebnisse zeigen, dab der antioxidative Effekt auf die An- wesenheit von Carvacrol und Thymol im etherischen O1 zur/ickgefiihrt werden kann. Abstract. In this study, four samples of essential oils ob- tained from plant species with a wide distribution in Greece and economic importance for the world-wide spice market and also carvacrol and thymol were tested for their possible antioxidant activity. The four plant spe- cies were Origanum vulgare subsp, hirtum, O. onites, Cori- dothymus capitatus and Satureja thymbra. The essential oils were chemically characterised by gas chromatogra- phy-ion trap detection. All the essential oils examined and also carvacrol and thymol were found to have anti- oxidant activity when tested on TLC plates and by measuring peroxide values of lard stored at 35 ~ C. The re- sults indicate that the antioxidant effect may be related to the presence of carvacrol and thymol in essential oils. Correspondence to: D. Boskou Introduction Synthetic antioxidants are often used in the food industry because they retard undesirable changes due to oxida- tion. However, in recent years some toxicity concerns and a trend among consumers toward "all natural ingredi- ents" have resulted in a pronounced activity in the field of natural additives. Herbs and spices, used world-wide for culinary PUrposes, have gained the interest of many research groups. Various extracts obtained from such sources have been assessed as potent antioxidants in lipid systems [1-5]. Among the plants studied, those of the Labiatae (La- miaceae), family have been often used to extract active components [6-11]. The relationship between chemical structure of extracts obtained from various tissues of such plants and antioxidant activity has not been thor- ougly investigated [6, 7]. Also, very little is known about the extent to which essential oils contribute to the antioxi- dant activity of certain spices. Farag et al. [12-14], using simple model systems composed of refined cottonseed oil or emulsions, found that essential oils obtained from plants of the Labiatae family exhibit antioxidant activity. Although the results of these studies were not conclusive it is clear that there is a relationship between the inhibi- tion of hydroxyperoxide formation and the presence of phenols such as thymol and eugenol in some essential oils. Their experiments, however, did not include "ore- gano" essential oil, which contains a high amount of car- vacrol, an isomer of thymol. The vernacular name "ore- gano" is attributed to a vast number of species in over a dozen genera of different families. Today it is generally accepted that oregano is in fact a characteristic flavour produced by a number of plant species that yield carva- crol-rich essential oils [15-18]. In this preliminary study four samples of essential oils obtained from plant species with a wide distribution in Greece and of economic importance for the world-wide spice market were tested for their possible antioxidant ac- tivity. These four plant taxa were: Origanum vulgare L. subsp, hirtum (Link) Ietswaart (commercially known