Supplementation with Carotenoids Inhibits Singlet Oxygen-Mediated Oxidation of Human Plasma Low-Density Lipoprotein

Abstract

To study the role of carotenoids in the antioxidant defense against oxidative modification of low-density lipoprotein (LDL) particles, human LDL rich in β-carotene and lycopene was prepared from a healthy volunteer following long-term supplementation with tomato juice. This carotenoid-supplemented LDL accumulated cholesteryl ester hydroperoxides (CE-OOH) more slowly than the LDL prepared before supplementation when the suspensions containing these LDL were subjected to a singlet oxygen-generating system. However, there was no significant difference in the rate of CE-OOH accumulation between the two suspensions when they were exposed to a water-soluble radical generator. Therefore, it is strongly suggested that supplementation of LDL with carotenoids mainly improves the antioxidant defense against the attack of singlet oxygen. Keywords: Carotenoids; singlet oxygen; low-density lipoprotein; atherosclerosis