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Ubiquinol-10 protects human low density lipoprotein more efficiently against lipid peroxidation than does alpha-tocopherol.
Proc Natl Acad Sci U S A 1991; 88(5):1646-50PN

Abstract

The temporal disappearance of natural antioxidants associated with human low density lipoprotein (LDL) in relation to the appearance of various classes of lipid hydroperoxides was investigated under three types of oxidizing conditions. Freshly isolated LDL from plasma of healthy subjects was free of detectable amounts of lipid hydroperoxides as measured by HPLC postcolumn chemiluminescence detection. Exposure of such LDL to a mild, constant flux of aqueous peroxyl radicals led to rapid and complete oxidation of ubiquinol-10, followed by slower partial depletion of lycopene, beta-carotene, and alpha-tocopherol. After an initial lag period of complete inhibition of detectable lipid peroxidation, formation of hydroperoxides of cholesterol esters, triglycerides, and phospholipids was observed. The onset of detectable lipid peroxidation corresponded closely with the completion of ubiquinol-10 consumption. However, small amounts of ascorbate, present as a contaminant in the LDL preparation, rather than ubiquinol-10 itself were responsible for the initial lag period. Thus, complete consumption of ubiquinol-10 was preceded by that of ascorbate, and exposure of ascorbate-free LDL to aqueous peroxyl radicals resulted in immediate formation of detectable amounts of lipid hydroperoxides. The rate of radical-mediated formation of lipid hydroperoxides in ascorbate-free LDL was low as long as ubiquinol-10 was present, but increased rapidly after its consumption, even though more than 80% and 95% of endogenous carotenoids and alpha-tocopherol, respectively, were still present. Qualitatively similar results were obtained when peroxyl radicals were generated within LDL or when the lipoprotein was exposed to oxidants produced by activated human polymorphonuclear leukocytes. LDL oxidation was reduced significantly by supplementing the lipoprotein preparation with physiological amounts of either ascorbate or ubiquinol-10. Our data show that ubiquinol-10 is much more efficient in inhibiting LDL oxidation than either lycopene, beta-carotene, or alpha-tocopherol.

Authors+Show Affiliations

Heart Research Institute, Sydney, New South Wales, Australia.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

2000375

Citation

Stocker, R, et al. "Ubiquinol-10 Protects Human Low Density Lipoprotein More Efficiently Against Lipid Peroxidation Than Does Alpha-tocopherol." Proceedings of the National Academy of Sciences of the United States of America, vol. 88, no. 5, 1991, pp. 1646-50.
Stocker R, Bowry VW, Frei B. Ubiquinol-10 protects human low density lipoprotein more efficiently against lipid peroxidation than does alpha-tocopherol. Proc Natl Acad Sci USA. 1991;88(5):1646-50.
Stocker, R., Bowry, V. W., & Frei, B. (1991). Ubiquinol-10 protects human low density lipoprotein more efficiently against lipid peroxidation than does alpha-tocopherol. Proceedings of the National Academy of Sciences of the United States of America, 88(5), pp. 1646-50.
Stocker R, Bowry VW, Frei B. Ubiquinol-10 Protects Human Low Density Lipoprotein More Efficiently Against Lipid Peroxidation Than Does Alpha-tocopherol. Proc Natl Acad Sci USA. 1991 Mar 1;88(5):1646-50. PubMed PMID: 2000375.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Ubiquinol-10 protects human low density lipoprotein more efficiently against lipid peroxidation than does alpha-tocopherol. AU - Stocker,R, AU - Bowry,V W, AU - Frei,B, PY - 1991/3/1/pubmed PY - 1991/3/1/medline PY - 1991/3/1/entrez SP - 1646 EP - 50 JF - Proceedings of the National Academy of Sciences of the United States of America JO - Proc. Natl. Acad. Sci. U.S.A. VL - 88 IS - 5 N2 - The temporal disappearance of natural antioxidants associated with human low density lipoprotein (LDL) in relation to the appearance of various classes of lipid hydroperoxides was investigated under three types of oxidizing conditions. Freshly isolated LDL from plasma of healthy subjects was free of detectable amounts of lipid hydroperoxides as measured by HPLC postcolumn chemiluminescence detection. Exposure of such LDL to a mild, constant flux of aqueous peroxyl radicals led to rapid and complete oxidation of ubiquinol-10, followed by slower partial depletion of lycopene, beta-carotene, and alpha-tocopherol. After an initial lag period of complete inhibition of detectable lipid peroxidation, formation of hydroperoxides of cholesterol esters, triglycerides, and phospholipids was observed. The onset of detectable lipid peroxidation corresponded closely with the completion of ubiquinol-10 consumption. However, small amounts of ascorbate, present as a contaminant in the LDL preparation, rather than ubiquinol-10 itself were responsible for the initial lag period. Thus, complete consumption of ubiquinol-10 was preceded by that of ascorbate, and exposure of ascorbate-free LDL to aqueous peroxyl radicals resulted in immediate formation of detectable amounts of lipid hydroperoxides. The rate of radical-mediated formation of lipid hydroperoxides in ascorbate-free LDL was low as long as ubiquinol-10 was present, but increased rapidly after its consumption, even though more than 80% and 95% of endogenous carotenoids and alpha-tocopherol, respectively, were still present. Qualitatively similar results were obtained when peroxyl radicals were generated within LDL or when the lipoprotein was exposed to oxidants produced by activated human polymorphonuclear leukocytes. LDL oxidation was reduced significantly by supplementing the lipoprotein preparation with physiological amounts of either ascorbate or ubiquinol-10. Our data show that ubiquinol-10 is much more efficient in inhibiting LDL oxidation than either lycopene, beta-carotene, or alpha-tocopherol. SN - 0027-8424 UR - https://www.unboundmedicine.com/medline/citation/2000375/Ubiquinol_10_protects_human_low_density_lipoprotein_more_efficiently_against_lipid_peroxidation_than_does_alpha_tocopherol_ L2 - https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/2000375/ DB - PRIME DP - Unbound Medicine ER -