Inhibitory effect of Allium ascalonicom hydroalcoholic extract on low-density lipoprotein (LDL) oxidation induced by CuSO4 in vitro

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 Allium ascalonicom hydroalcoholic extract (AAE) on LDL oxidation induced by CuSO4 quantitatively in vitro. Oxidation of LDL was incubated with CuSO4 and the formation of conjugated dienes and thiobarbituric acid reactive substances (TBARS) was assessed. It was demonstrated that AAE is able to inhibit CuSO4-induced LDL oxidation. AAE showed an increase lag time rate of 11.2, 33.7 and 50.4% at concentrations ranging from 4 to 12 mg/ml, respectively, against oxidation in vitro. The inhibitory effects of the AAE on LDL oxidation were dose-dependent at concentrations ranging from 4 to 12 mg/ml. Total antioxidant capacity of AAE was 2.10 +/- 0.20 nmol of ascorbic acid equivalents/g AAE. The AAE showed remarkable scavenging activity on 2, 2-diphenyl-picrylhydrazyl (DPPH) (IC50 3.68 +/- 0.14 mu g/ml). This study showed that AAE prevented the oxidation of LDL in vitro and it may suggest that they have a similar effect in vivo.