462 Research Article Received: 23 March 2009 Revised: 30 September 2009 Accepted: 16 October 2009 Published online in Wiley Interscience: 1 December 2009 (www.interscience.wiley.com) DOI 10.1002/jsfa.3840 The influence of organ, season and drying method on chemical composition and antioxidant and antimicrobial activities of Juniperus phoenicea L. essential oils Monia Ennajar, a,b Jalloul Bouajila, c ∗ Ahmed Lebrihi, d Florence Mathieu, d Arlette Savagnac, e Manef Abderraba, a Aly Raies f and Mehrez Romdhane b Abstract BACKGROUND: Juniperus phoenicea is an important medicinal plant. In the present study, essential oils (18 samples) from leaves and berries of Juniperus phoenicea L. (Cupressaceae), obtained by various drying methods and in different collection months, were analysed by gas chromatography–mass spectrometry and also evaluated for in vitro antimicrobial and antioxidant activities. Correlations were studied between antimicrobial activity and the chemical composition of essential oils. RESULTS: Sixty-seven compounds were identified in essential oils, representing 97.7 – 100%. Essential oils were dominated by monoterpenes and sesquiterpenes, which presented 35.0 – 93.3% and 6.7 – 62.0%, respectively, depending of organ, season and drying method. Antimicrobial tests showed that essential oils strongly inhibited the growth of Gram-positive microorganisms and Mucor ramamnianus, but was inactive against Gram-negative strains. Antioxidant activity was tested using the ABTS radical-scavenging assay. Most samples showed good activity (the best IC 50 = 41.7 ± 1.5 mg L −1 ). CONCLUSIONS: It could be concluded that drying of leaves of J. phoenicea in the sun and berries in oven-drying was more suitable and was recommended for obtaining higher essential oil yield, but for a higher percentage of some special components such as α-pinene and δ-3-carene shade-drying was more suitable. c  2009 Society of Chemical Industry Keywords: Juniperus phoenicea. L (Cupressaceae); essential oil; GC-MS; antimicrobial activity; antioxidant activity; ABTS INTRODUCTION The history of medicinal and aromatic plants is associated with the development of civilizations. In all regions of the world, the history of peoples shows that these plants have always occupied an important place in medicine, the composition of perfumes, food and in cooking. China – birthplace of herbal medicine – India, the Middle East, especially the Arabo-Muslim world, Egypt, Greece and Rome represent civilizations in which aromatic and medicinal plants had an important place. Tunisia is one of the countries in the Mediterranean with large variations in climate from north to south, and presents a field of choice for the development of these cultures. These species contain essential oils and other substances that can be exploited as food (aromas), traditional medicine and for industrial purposes (food, perfume, cosmetics, pharmaceutical, etc.). Moreover, essential oils are proven to have various pharmacological effects, such as spasmolytic, carminative, hepatoprotective, antiviral and anticarcinogenic. 1,2 Essential oils are concentrated odorous substances obtained from plants together with water vapour or hydrodistillation expression (cold pressure). There are now approximately 3000 essential oils, of which approximately 300 are actually marketed mainly for industrial flavourings and fragrances. The current trend of consumers, however, to seek a more natural diet has led to a renewed interest by scientists in these substances. For two decades, studies have been conducted on the development of new applications and exploitation of the natural properties of essential oils in food. Furthermore, antimicrobial effects of different ∗ Correspondence to: Jalloul Bouajila, Laboratoire des Interactions Mol´ eculaires et R´ eactivit´ e Chimique et Photochimique UMR CNRS 5623, Universit´ e Paul- Sabatier, 118 route de Narbonne, F-31062 Toulouse, France. E-mail: bouajila@cict.fr a Laboratoire de Physicochimie des Mat´ eriaux, IPEST, BP51, La Marsa 2070, Tunisia b Unit´ e de Mod´ elisation, Analyse et commande des syst` emes, Ecole Nationale d’Ing´ enieur, 6029 Gab´ es, Tunisia c Laboratoire des Interactions Mol´ eculaires et R´ eactivit´ e Chimique et Photochim- ique UMR CNRS 5623, Universit´ e Paul-Sabatier, F-31062 Toulouse, France d Universit´ e de Toulouse, LGC UMR 5503 (CNRS/INPT/UPS), ENSAT/INPT, BP 32 607, Auzeville-Tolosane, 31326 Castanet-Tolosan, France e UFR SVT, Universit´ e Paul-Sabatier, F-31062 Toulouse, France f LMBA. Facult´ e des Sciences de Tunis. Campus Universitaire 2092 El Manar II, Tunisia J Sci Food Agric 2010; 90: 462–470 www.soci.org c  2009 Society of Chemical Industry