EVALUATION OF THE ANTIOXIDANT ACTIVITY OF ESSENTIAL OILS FROM CAPER (CAPPARIS SPINOSA) AND SEA FENNEL (CRITHMUM MARITIMUM) BY DIFFERENT METHODS T. KULISIC-BILUSIC 1,2,4 , IVICA BLAŽEVIC ´ 1 , BRANKA DEJANOVIC ´ 3 , MLADEN MILOŠ 1 and GRETA PIFAT 3 1 Faculty of Chemistry and Technology University of Split Teslina 10/V, 21000 Split, Croatia 2 Department of Food and Nutrition Technical University of Munich Biofunctionality of Food, Life Science Center Weihenstephan Hochfeldweg 1, 85354 Freising, Germany 3 Rudjer Boskovic Institute Bijenicka, Zagreb, Croatia Accepted for Publication March 17, 2009 ABSTRACT In this study, essential oils from wild-grown caper (Capparis spinosa L.) and sea fennel (Crithmum maritimum L.) from Dalmatia (Croatia) were iso- lated by hydrodistillation and analyzed by gas chromatography with mass spectrometry. Methyl isothiocyanate (92.06%) was detected as major compo- nent of essential oil from caper leaves and flower buds, while limonene (58.37%), sabinene (26.46%), terpinene-4-ol (5.59%) and g-terpinene (2.81%) were identified as dominant compounds in sea fennel essential oil. Tested essential oils did not exhibit radical-scavenging activity by 1,1- diphenyl-2-picrylhydrazyl hydrate method, while they showed the antioxidant activity by b-carotene bleaching method and thiobarbituric acid reactive species assay. In addition, sea fennel essential oil exhibited very high inhibi- tory effect on the oxidation of human low-density lipoprotein. PRACTICAL APLICATIONS Antioxidants are indispensable for the food preservation from oxidative deterioration, as well as for the protection of unsaturated lipids in animal and 4 Corresponding author. TEL: + 385 21 329465; FAX: + 385 329461; EMAIL: tea@ktf-split.hr DOI: 10.1111/j.1745-4514.2009.00330.x Journal of Food Biochemistry 34 (2010) 286–302. © 2010, Wiley Periodicals, Inc. 286