β-Carotene inhibits the oxidative modification of low-density lipoprotein

• Published in: Biochimica et biophysica acta Vol. 1086; no. 1; pp. 134 - 138
• Main Authors: Jialal, Ishwarlal, Norkus, Edward P., Cristol, Louis, Grundy, Scott M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.10.1991; Elsevier
• Subjects: Antioxidant; Antioxidants - pharmacology; Atherosclerosis; Atherosclerosis (general aspects, experimental research); beta Carotene; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Carotenoids - pharmacology; Cell-Free System; Human macrophage; Humans; In Vitro Techniques; Lipoprotein; Lipoproteins, LDL - drug effects; Lipoproteins, LDL - metabolism; Macrophages - metabolism; Medical sciences; Oxidation-Reduction - drug effects; β-Carotene; PBS; LDL; Atherosclerosis; Ox; TBARS; Lipoprotein; MDA; Antioxidant; Human macrophage; β-Carotene; Human; Lipoprotein LDL; Carotene; Cardiovascular disease; Oxidation; Macrophage
• ISSN: 0005-2760; 0006-3002; 1879-145X
• DOI: 10.1016/0005-2760(91)90164-D

Several lines of evidence indicate that oxidized LDL (Ox-LDL) may promote atherogenesis. Hence, the role of antioxidants in the prevention of LDL oxidation needs to be determined. β-Carotene, in addition to being an efficient quencher of singlet oxygen, can also function as a radical-trapping antioxidant. Since previous studies have failed to show that β-carotene inhibits LDL oxidation, we re-examined its effect on the oxidative modification of LDL. For these studies, LDL was oxidized in both a cell-free (2.5 μM Cu 2+ in PBS) and a cellular system (human monocyte macrophages in Ham's F-10 medium). β-Carotene inhibited the oxidative modification of LDL in both systems as evidenced by a decrease in the lipid peroxide content (thiobarbituric-acid-reacting substances activity), the negative charge of LDL (electrophoretic mobility) and the formation of conjugated dienes. By inhibiting LDL oxidation, β-carotene substantially decreased its degradation by macrophages. β-Carotene (2 μM) was more potent than α-tocopherol (40 μM) in inhibiting LDL oxidation. Thus, β-carotene, like ascorbate and α-tocopherol, inhibits LDL oxidation and might have an important role in the prevention of atherosclerosis.