en پژوهشي Research Article Oxidation of low-density lipoprotein (LDL) has been strongly suggested as a key factor in the pathogenesis of atherosclerosis. Thus, the inclusion of some anti-oxidant compounds in daily dietary food stuff may inhibit the production of oxidized LDL and may decrease both the development and the progression of atherosclerosis. The present work investigated the inhibitory effects of extract of Allium cepa (onion) on LDL oxidation induced by CuSO ? quantitatively in vitro and compared with extract of Allium ascalonico (shallot) and Allium sativum (garlic). LDL was incubated with CuSO4 and the formation of conjugated dienes and thiobarbituric acid reactive substances (TBARS) were monitored as markers of LDL oxidation. Inhibition of this Cu-induced oxidation was studied in the presence of extracts of Allium ascalonicom, Allium cepa and Allium sativum . It was demonstrated that extract of Allium cepa as well as Allium ascalonicom and Allium sativum were able to inhibit LDL oxidation and increase the resistance of LDL against oxidation in vitro. The pattern of inhibition was in this order: Allium sativum >Allium ascalonicom>Allium cepa. This study showed that extract of Allium ascalonicom, Allium cepa and Allium sativum prevented the oxidation of LDL in vitro and it may suggest that they have the similar effect in vivo . 61 0 http://ijpt.iums.ac.ir/browse.php?a_code=A-10-100-240&slc_lang=en&sid=1 H. Ahmadvand 1003194753284600810 1003194753284600810 No M. Ani 1003194753284600811 1003194753284600811 No A. A. Moshtaghie 1003194753284600812 1003194753284600812 No