Available online www.jocpr.com Journal of Chemical and Pharmaceutical Research, 2015, 7(2):42-46 Research Article ISSN : 0975-7384 CODEN(USA) : JCPRC5 42 Inhibitory effects of myrtle (Myrtus communis L.) leaves hydroalcoholic extract on LDL oxidation in vitro Bahador Fadaei 1 , Hassan Ahmadvand 2,3* , Maryam Ghasemi Dehnoo 2 and Sako Mirzaei 1,4 1 Department of Biology, Kurdistan Science and Research Branch, Islamic Azad University, Sanandaj, Iran 2 Razi Herbal Medicine Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran 3 Department of Biochemistry, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran 4 Department of Biology, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran _____________________________________________________________________________________________ ABSTRACT Oxidation of low-density lipoprotein (LDL) has been strongly implicated in the pathogenesis of atherosclerosis. The use of some compound in dietary food stuff include Myrtle (Myrtus communis L.) leaves hydroalcoholic extract (ME) may lead to the inhibition of production of oxidized LDL and may decrease both the development and the progression of atherosclerosis. The present work investigated the effects of ME on LDL oxidation induced-CuSO4 quantitatively in vitro. Fasting blood samples from normal people after an overnight fasting were collected and then LDL was isolated. LDL was incubated without CuSO4 as control and incubated with CuSO4 and several concentration of ME (0.2, 2 and 20 μg/ml); and measured the formation of conjugated dienes, lag time and thiobarbituric acid reactive substances (TBARS). Inhibition of this Cu-induced oxidation was studied in the presence of several concentration of ME (0.2, 2 and 20 μg/ml). It was demonstrated that ME is able to inhibit CuSO4-induced LDL oxidation and decrease the resistance of LDL against oxidation in vitro. Myrtle (Myrtus communis L.) leaves extract showed an increase rate of 5%, 42% and 50% at concentrations ranging from 0.2 to 20 μg /ml, respectively. The inhibitory effects of the ME on LDL oxidation were dose-dependent at concentrations ranging from 0.2 to 20 μg /ml. This study showed that ME prevented the oxidation of LDL in vitro and it may suggest that they have the similar effect in vivo. Keywords: Myrtle (Myrtus communis L.) leaves extract, Low-density lipoprotein (LDL) oxidation _____________________________________________________________________________________________ INTRODUCTION LDL oxidation plays an important role in the genesis and development of atherosclerosis [1, 2]. The consumption of oxidant substances in foods causes LDL to oxidize and this can result in initiation and progression of atherosclerosis [2-4]. When LDL is oxidized, its tendency to its receptor is reduced [2] . The accumulation of oxidized LDL in macrophages leads to the formation of foamy cells and also the formation of atherosclerosis [5, 6]. Using antioxidants such as vitamin E and plants such as myrtle leaves, which are rich in antioxidants, we can prevent the oxidation of LDL, and thus prevent the development of atherosclerosis [5, 6] . The pathogeneses of atherosclerosis is a complex process, but there is some evidence to suggest that lipids and LDL oxidation are among of the major events that are involved in the formation of atherosclerotic plaques [7-10] . On the other hand, atherosclerosis is also known as an inflammatory disease, and it is said that oxidative and inflammatory factors in the form of a defective cycle are involved in the initiation and development of atherosclerosis [7-10]. The scientific name of a plant used in this study is “Myrtus communis L.” which is known as “myrtle” by local name [11]. Myrtle is an evergreen plant in the form of shrub and belongs to Myrtaceae family which exists in Europe, Asia and America [11]. The leaves of this plant is strongly aromatic and major chemical constituents of its extracts include 1, 8-cineole (18.3 %), Linalool (16.3%) , Myrtinil acetate (14.5%) , These compounds have