International Journal of Bio-Technology and Research (IJBTR) ISSN 2249-6858 Vol. 3, Issue 3, Aug 2013, 1-4 © TJPRC Pvt. Ltd. ANTI OXIDANT ACTIVITY OF PALIURUS SPINA-CHRISTI METHANOLIC EXTRACT LUMA TAHA AHMED 1 , KHULOOD W. ABOOD 2 , QUTUBA GHANIM 3 , NABIL KHALAF IBRAHIM 4 & AHMED SAMEER AL-NAIM 5 1 Branch of Microbiology, College of Medicine, University of Diyala, Diyala, Iraq 2,4 Department of Biotechnology, College of Science, University of Al-Nahrain, Baghdad, Iraq 3 Branch of Pharmacology, College of Medicine, University of Diyala, Diyala, Iraq 5 Branch of Community, College of Medicine, University of Baghdad, Baghdad, Iraq ABSTRACT Paliurus pina-christi a traditional Mediterranean and Asiatic medicinal plant, chemical investigation of Paliurus spina-christi fruits and leaves indicated the presence of the flavonoids ,isoquercitin, rutin for the first time the chemical composition of stem analyzed by HPLC, the results revealed presence of the following phenolic compounds(gallic acid, caffeic acid, syringicacid and epichotechn)at retention time(4.632,19.418,20.408and21.871)respectively The antioxidant activity of oxidative stress was detected by measuring the optical density at 512nm,different concentrations of P. spina-christi methanolic extract (100,300,500 and700)μg/ml exhibit different antiradical activity was( 82.00,78.50 ,69.88and 62.38)% the correlation between anti-radical activity and concentration of methanolic extract was not linear but quadratic(curvilinear) denoting that at higher concentration it act as pro-oxidant while at low concentration it act as anti oxidant KEYWORDS: Paliurus Spina-Christi, Phenolic Compounds, Antioxidants INTRODUCTION Reactive free radicals, such as super oxide anion(O°¯ ), hydroxyl radical (°OH),and peroxyl radical (ROO°), are particularly reactive and are known to be a biological product in reducing molecular oxygen(Williams and Jeffery,2000). The uncontrolled condition of free radicals is considered as an important factor in the tissue damage induced by several pathophysiology (Dinger et.al., 2005).Oxidative stress is now considered to be important in the pathogenesis of skin disease, like vitiligo & alopecia areata an insufficient antioxidant system together with increased levels of reactive oxygen species(ROS) have been suggested to be important in the pathogenesis of these diseases(Al-Azawi,2010). Some substances can act as either antioxidants or pro-oxidants, depending on the specific set of conditions. pro-oxidants are chemicals that induce oxidative stress, through either creating reactive oxygen species or inhibiting antioxidant systems (Puglia and Powell,1984). Han et.al., (1996) reported that important variables include the concentration of the chemical and whether oxygen or transition metals are present. Examples of pro-oxidants are: (Metals, Vitamins, Uric acid, Hyperhomocysteinemia and Anticancer drug) (Han et.al., 2005). More than 200 different biologically active substances have been isolated from plant extract ,among them organosulphur compounds such as allicin ,azoenes and diallyl trisulfide .Eugenol, phenolic compounds the most important biologically active compound found in many plant extract (Kahkonen etal.,1999);(Aly and Bahiel,2008). Paliurus spina-christi is a perennial thorny shrub of wide spread distribution in dry and rocky places in the Mediterranean region and Asia (Brantner et.al.,1996). Rich source of flavonoids isoquercitin ,rutin ,hyperoside (Dalakishvili et.al.,1986) (Kustrak et.al.,1990) and a quercetin -3-O-triglycoside (Brantner and Males,1990).