Effects of ubiquinol-10 and beta-carotene on the in vitro susceptibility of low-density lipoprotein to copper-induced oxidation

ABSTRACT

Dietary antioxidant intake has been reported to be inversely associated with coronary artery disease. To clarify the possible role of lipophilic antioxidants in the prevention of atherosclerosis, we investigated the effects of ubiquinol-10 and beta-carotene on the susceptibility of low-density lipoprotem [LDL] to oxidative modification. In this study, first "ubiquinol-10 and beta-carotene" were added to plasma and incubated for 3hr at 37°C. Then, the LDL fraction was separated by ultracentrifugation. The oxidizability of LDL was estimated by measuring conjugated diene[CD], lipid peroxides and thiobarbituric acid-reactive substances [TEARS] after cupric sulfate solution was added. We showed that ubiquinone-10 and P-carotene significantly [p<0.01 by ANOVA] and dose-dependently prolonged the lag time before initiation of oxidation reaction. Also, these two compounds suppressed the formation of lipid peroxides and TEARS more markedly than others. The ability of them to prolong lag time and suppression of lipid peroxides and TEARS formation resulted to be in the following order ubiquinol-10> p-carotene.LDL exposed to the lipophilic antioxidants in vitro reduced oxidizability. These findings suggest that ubiquinol-10 and p-carotene have a role in ameliorating atherosclerosis