In vitro screening of essential oil from young and mature leaves of Artemisia scoparia compared to its major constituents for free radical scavenging activity Harminder Pal Singh a, * , Shalinder Kaur b , Sunil Mittal a , Daizy R. Batish b , Ravinder K. Kohli a,b a Department of Environment and Vocational Studies, Panjab University, Chandigarh 160 014, India b Department of Botany, Panjab University, Chandigarh 160 014, India article info Article history: Received 18 July 2009 Accepted 18 January 2010 Keywords: Artemisia scoparia (redstem wormwood) Leaf essential oil GC–MS analyses Monoterpenoids DPPH scavenging activity Antioxidant activity abstract The present study investigated the chemical characterization, and antioxidant activity of essential oil hydrodistilled from young and mature leaves of Artemisia scoparia. GC–MS analyses revealed a monoter- penoid nature (64–67%) with 44 and 31 constituents in young and mature leaves oil, respectively. The oil from young leaf contained greater amount of oxygenated compounds. b-Myrcene (24.13%) and p-cymene (27.06%) were the major constituents in young and mature leaves oil, respectively. A. scoparia leaf oils (25–200 lg/ml) exhibited a strong 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity and antiox- idant activity against hydroxyl radical and hydrogen peroxide. However, the activities of major constit- uent monoterpenes, b-myrcene and p-cymene, were less. In general, the DPPH radical scavenging and antioxidant activity was in the order: mature leaf oil > young leaf oil > b-myrcene > p-cymene. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Reactive oxygen species (ROS: superoxide anion radicals, O 2 Å  ; hydroxyl radicals, OH Å ; hydrogen peroxide, H 2 O 2 ; and singlet oxy- gen, 1 O 2 ) are the chemically reactive ions, generated as byproducts of primary metabolic activities. Excess of ROS/free radicals damage enzymatic machinery, oxidize carbohydrates, proteins, lipids and DNA, and thus induce disease and cellular injury (Halliwell and Gutteridge, 1999). The deleterious effects of ROS-mediated cellular injury have aroused the attention for the search of antioxidants that can be supplemented into the dietary foodstuffs. To scavenge free radicals, reduce lipid peroxidation, and prevent microbial deg- radation of food, synthetic antioxidants (BHA, butylated hydroxy- anisole; BHT, butylated hydroxytoluene) have been widely used as food additives (Pokorny ´ , 2007). However, due to increasing awareness among people for the use of safer compounds there has been a shift towards the use of natural compounds as antioxi- dants (Singh et al., 2008b). In this direction, essential oils and their pure components due to their non-toxic nature and a wide spec- trum of biological activities (Batish et al., 2008), and potential to control the free radicals are now being explored as flavoring agents in foods (Bakkali et al., 2008). In fact, essential oil from various aro- matic plants has been a subject of intense research due to their multifunctional uses other than classical roles as raw material in pharmaceuticals, food industries and perfumeries. These include: antimicrobial, antifungal, insecticidal, insect-repellant, bioherbi- cidal, and free radical scavenging activity (Batish et al., 2004, 2008; Bakkali et al., 2008; Isman, 2006; Ramezani et al., 2002; Singh et al., 2005; Singh et al., 2008a, 2008b; Wei and Shibamoto, 2007). In fact, these volatiles/essential oils provide an important defense strategy to plants and also depict an evolutionary relation- ship with their functional roles in plants per se (Batish et al., 2008). Artemisia scoparia (redstem wormwood; Asteraceae) is a faintly scented annual herb widespread and common throughout the world, particularly Southwest Asia and Central Europe (Anony- mous, 1993). In India, it is abundant in western Himalayas (up to 2100 m), Punjab, and upper Gangetic plains. The success of A. scoparia may be attributed to presence of phytotoxins – the volatile essential oil besides the other nonvolatile secondary products (Singh et al., 2008a; Singh et al., 2009a). It has been established that aerial parts of A. scoparia yield volatile essential oil that has medicinal value (Anonymous, 1993) and insecticidal activity (Neg- ahban et al., 2006). It possesses antibacterial, anticholesterolemic, antipyretic, antiseptic, cholagogue, diuretic, purgative, and vasodi- lator activity, and is also used for treatment of gall bladder inflam- mation, hepatitis, and jaundice (Yeung, 1985). Earlier, researchers have documented that volatile oil from A. scoparia is rich in oxy- genated monoterpenoids and the chemical composition varies sig- nificantly with geographical region (Cha et al., 2005; Safaei-Ghomi et al., 2005; Mirjalili et al., 2007), yet no study has been undertaken to evaluate the variability in chemical constituents and the antiox- idant activity of the essential oil with leaf age/growth stage. There- fore, a study was planned to extract and characterize essential oil 0278-6915/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.fct.2010.01.017 * Corresponding author. Tel.: +91 172 2534095. E-mail address: hpsingh_01@yahoo.com (H.P. Singh). Food and Chemical Toxicology 48 (2010) 1040–1044 Contents lists available at ScienceDirect Food and Chemical Toxicology journal homepage: www.elsevier.com/locate/foodchemtox