H: Health, Nutrition & Food Relation between Chemical Composition or Antioxidant Activity and Antihypertensive Activity for Six Essential Oils Yan Yvon, Emmanuel Guy Raoelison, Ren´ e Razafindrazaka, Adolphe Randriantsoa, Mehrez Romdhane, Naziha Chabir, Mounira Guedri Mkaddem, and Jalloul Bouajila Abstract: Six essential oils (EOs), Juniperus phoenicea (leaves and berries), Thymus capitatus, Lauris nobilis, Melaleuca armillaris, and Eucalyptus gracilis, were screened for their antioxidant and antihypertensive activity as well as their chemical compositions. We identified and quantified 24 compounds (representing 99.8% of total oil) for J. phoenicea leaves, 14 compounds (representing 98.8% of total oil) for J. phoenicea berries, 11 compounds (representing 99.6% of total oil) for T. capitatus, 32 compounds (representing 98.9% of total oil) for L. nobilis, 32 compounds (representing 98.7% of total oil) for M. armillaris, and 26 compounds (representing 99.3% of total oil) for E. gracilis. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, the antioxidant activity was in the range of 0.59 to 2183.6 mg/L, whereas T. capitatus (1.24 ± 0.05 mg/L) gave the best activity in the 2,2 ′ -azinobis-3-ethylbenzothiazoline-6-sulfonate assay. Antihypertensive activity was evaluated by testing the vasorelaxing capacity of EOs on rat aorta precontracted by phenylephrine (10 -6 M). T. capitatus and L. nobilis were most active for an antihypertensive activity (29 ± 3 and 59 ± 2 mg/L, respectively). Correlations between chemical composition or antioxidant activity and/or antihypertensive activity were studied. Significant correlation has been found for antihypertensive activity and p-cymene (R 2 = 0.86), β -elemene (R 2 = 0.90), and β -myrcene (R 2 = 0.76). A good correlation has been found between antihypertensive activity and antioxidant activity by DPPH assay (R 2 = 0.98). Antioxidant activity can contribute to the prevention of the increase of the blood pressure. According to the literature, no study has been reported until now of correlation between antihypertensive activity and antioxidant activity. Natural EOs can find its interest and application in a medicinal area. Keywords: antihypertensive activity, antioxidant activity, essential oil, Eucalyptus gracilis,Juniperus phoenicea, Lauris nobilis, Melaleuca armillaris, Thymus capitatus Introduction Essential Oils (EOs) are mainly used for their medicinal properties (Burt 2004; Bakkali and others 2008). Determinations of biological activities have been commonly found with the studies of chemical composition of EOs. Antimicrobial tests carried out for Juniperus phoenicea leaves and berries EOs have been described (Ennajar and others 2009). They showed that J. phoenicea EO strongly inhibited the growth of gram-positive microorganisms and fungi (Mucor ramamnianus), but were inactive against gram-negative strains (Ennajar and others 2009). Cytotoxic activities were also shown for J. phoenicea leaves and berries EOs (El-Sawi and others 2007). Antimicrobial and antibacterial activities were tested for Thymus capitatus EO (Kandil and others 1994; Daferera and others 2003; MS 20120131 Submitted 1/26/2012, Accepted 5/12/2012. Authors Yvon and Bouajila are with Laboratoire des Interactions Mol´ eculaires et R´ eactivit´ e Chim- ique et Photochimique, Univ. de Toulouse, UMR CNRS 5623, Universit´ e Paul- Sabatier, 118 route de Narbonne, F-31062 Toulouse, France. Authors Raoelison, Razafindrazaka, and Randriantsoa are with Laboratoire de Phytochimie et Standard- isation, IMRA, BP: 3833, Antananarivo 101, Madagascar. Authors Romdhane, Chabir, and Mkaddem are with Unit´ e de Mod´ elisation, Analyse et commande des syst` emes, Ecole Nationale d’Ing´ enieur, 6029 Gab´ es, Tunisia. Direct inquiries to author Bouajila (E-mail: bouajila@cict.fr). Bounatirou and others 2007; Amarti and others 2008), for Laurus nobilis EO (Barla and others 2007), for Eucalyptus gracilis EO (Ben Marzoug and others 2010), and for Melaleuca armillaris EO (Hayouni and others 2008). Study on the acetylcholinesterase (AChE) inhibitory capacity of L. nobilis EO from Portugal has been reported (Ferreira and others 2006). The antimalarial and cytotoxic activities of EO of M. armillaris were also evaluated elsewhere (Chabir and others 2011). They have found that the EO had mild activity against the chloroquine-resistant Plasmodium falciparum FcB1 strain (IC 50 = 27 mg/L) and a good value has been found concerning cytotoxic activity against MCF7 human breast cancer cells (IC 50 = 12 mg/L). The cardiovascular activity of some EOs was evaluated. Cardiovascular effects of Mentha x villosa and Hyptis fruticosa EOs have been reported (Guedes and others 2004; Santos and others 2007). Results have shown noticeable and beneficial effects for experiments carried out on rats. In intact and isolated rings of rat superior mesenteric artery, H. fruticosa EO induced concentration-dependent relaxations of tonus induced by 10 μM phenylephrine (Santos and others 2007). In addition, Guedes and others (2004) have shown that in isolated rat aortic rings, increasing concentrations of M. villosa EO was able to antagonize the effects of phenylephrine (1 mM), prostaglandin F2a (10 mM), and KCl (80 mM)-induced contractions. The vasorelaxant activity induced by M. villosa EO was attenuated significantly C  2012 Institute of Food Technologists R  H184 Journal of Food Science  Vol. 77, Nr. 8, 2012 doi: 10.1111/j.1750-3841.2012.02812.x Further reproduction without permission is prohibited