Copyright© Autumn 2016, Iran J Allergy Asthma Immunol. All rights reserved. 515 Published by Tehran University of Medical Sciences (http://ijaai.tums.ac.ir) ORIGINAL ARTICLE Iran J Allergy Asthma Immunol December 2016; 15(6):515-524. The Effect of Artemisia fragrans Willd: Essential Oil on Inducible Nitric Oxide Synthase Gene Expression and Nitric Oxide Production in Lipopolysaccharide-stimulated Murine Macrophage Cell Line Maryam Farghadan 1,2 , Hossein Ghafoori 3 , Faezeh Vakhshiteh 4 , Seyed Abolhassan Shahzadeh Fazeli 4 , Parvaneh Farzaneh 4 , and Parviz Kokhaei 1 1 Cancer Research Center, Semnan University of Medical Sciences, Semnan, Iran 2 Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran 3 Department of Biology, University of Guilan, Rasht, Iran 4 Human and Animal Cell Bank, Iranian Biological Resource Center (IBRC), ACECR, Tehran, Iran Received: 8 February 2016; Received in revised form: 27 June 2016; Accepted: 11 July 2016 ABSTRACT The genus Artemisia is estimated to comprise over 800 species with anti-cancer, anti-fungal, anti-oxidant and anti-inflammatory properties. Artemisia fragrans (A. fragrans), a species that belongs to genus Artemisia, is rich in monoterpenes and sesquiterpenes derivatives. Due to anti- inflammatory properties of monoterpenes and sesquiterpenes, we aimed to investigate the effect of A. fragrans essential oil on mRNA expression of inducible nitric oxide synthase (iNOS) gene and nitric oxide (NO) production in Lipopolysaccharide (LPS)-stimulated RAW264.7 cell line. NO, which is synthesized by iNOS, is the main macrophage-derived inflammatory mediator. The oil obtained from the A. fragrans was prepared from aerial parts of the plant. Chemical composition of essential oil was analyzed by gas chromatography–mass spectrometry (GC/MS).The cytotoxicity of various concentrations of essential oil was evaluated by mitochondrial reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test assay. The effect of different doses (1.75-7 mg/mL) of A. fragrans oil on mRNA expression of iNOS gene and NO production in LPS-stimulated RAW 264.7 cells was assessed by real-time PCR method and Griess reagent, respectively. In GC/MS analyses of A. fragrans oil, 32 compounds were identified. The main components of the oil were camphor and 1, 8-cineole. The results demonstrated that the essential oil of A. fragrans (1.75- 7 mg/mL), in a dose-dependent manner, inhibits mRNA expression of iNOS induced by LPS in the RAW264.7 cells without cytotoxic effect even at higher doses. The results of iNOS were consistent with the results of NO production. Our preliminary results suggest the possible anti-inflammatory effect of A. fragrans. Further studies are needed to determine the full pharmacokinetics of A. fragrans activity in vivo. Keywords: Artemisia fragrans; Essential oils; Inflammation; Macroghage; Gene expression; Nitric Oxide synthase Corresponding Authors: Parviz Kokhaei, PhD; Department of Immunology, Semnan University of Medical Sciences, Semnan, Iran. Tel: (+98 23) 3365 4362, Fax: (+98 23) 3365 4177. E-mail: parviz.kokhaei@ki.se Parvaneh Farzaneh, PhD; Human and Animal Cell Bank, Iranian Biological Resource Center (IBRC), ACECR, Tehran, Iran. Tel: (+98 21) 8852 5389, E-mail: pfarzaneh2000@yahoo.com