title: The Influence of L-Carnitine on Oxidative Modification of LDL In Vitro.
abstract: Owing to their structure and function, low-density lipoproteins (LDLs) are particularly susceptible to the oxidative modifications. To prevent against oxidative modification of LDL, L-carnitine, with endogenous small water-soluble quaternary amine possessing antioxidative properties, was used. The aim of this paper was to prove the in vitro influence of L-carnitine on the degree of oxidative modification of the lipid part (estimated by conjugated dienes, lipid hydroperoxides, and malondialdehyde levels) and the protein part (estimated by dityrosine and tryptophan levels) of LDL native and oxidized by cooper ions. The level of lipophylic LDL antioxidant-alpha-tocopherol was also measured.Oxidation of LDL by Cu(2+) enhanced lipid peroxidation. That was manifested by a statistically significant increase in the content of malondialdehyde (threefold), conjugated dienes (up to about 30%), and lipid hydroperoxides (up to about 50%). Cu(2+) ions were also the cause of oxidative modifications of the protein part of LDLs. It was manifested by a significant increase in dityrosine (by about 50%), whereas the level of tryptophan was significantly decreased threefold in relation to native LDL. Incubation of LDL with Cu(2+) ions also caused a significant sixfold decrease of alpha-tocopherol content in oxidized LDL. However, L-carnitine caused a decrease in the level of conjugated dienes, lipid hydroperoxide, malondialdehyde, and dityrosine by about 20% to 30%, and a significant increase (by about 50%) in the content of tryptophan in comparison with oxidative LDL and in a smaller degree significant changes with native LDL. Additionally, L-carnitine caused a significant twofold increase in alpha-tocopherol content in oxidized LDL.The above results indicate that L-carnitine protects the lipid as well as protein part of LDL particles against oxidative modifications, and this natural antioxidant might be used to prevent against diseases of oxidative origin.
authors.affiliation: Department of Inorganic and Analytical Chemistry, Medical University of Bialystok, Mickiewicza 2a, Box 1415-230, Bialystok, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Augustyniak
authors.forename: Anna
authors.initials: A
authors.lastname: Stankiewicz
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Skrzydlewska
references.citation: J Lipid Res. 1993 Dec;34(12):2135-45
references.pmid: 8301232
references.citation: J Chromatogr. 1979 Mar 1;162(3):408-13
references.pmid: 528606
references.citation: FASEB J. 1999 Jul;13(10):1113-20
references.pmid: 10385603
references.citation: Acta Pharmacol Sin. 2004 Aug;25(8):1038-44
references.pmid: 15301737
references.citation: J Chromatogr A. 1996 Apr 5;729(1-2):207-10
references.pmid: 9004941
references.citation: Ann Nutr Metab. 2000;44(2):75-96
references.pmid: 10970996
references.citation: J Lipid Res. 1970 Nov;11(6):583-95
references.pmid: 4100998
references.citation: J Lipid Res. 1993 Jul;34(7):1209-17
references.pmid: 8371068
references.citation: Arterioscler Thromb Vasc Biol. 2001 Apr;21(4):594-602
references.pmid: 11304478
references.citation: J Lipid Res. 2001 Oct;42(10):1664-70
references.pmid: 11590223
references.citation: Drugs R D. 2003;4(3):141-7
references.pmid: 12757399
references.citation: J Biol Chem. 1995 Mar 10;270(10):5158-63
references.pmid: 7890625
references.citation: Reprod Biomed Online. 2004 Apr;8(4):376-84
references.pmid: 15149558
references.citation: J Nat Prod. 2000 Jul;63(7):1035-42
references.pmid: 10924197
references.citation: J Biol Chem. 1951 Nov;193(1):265-75
references.pmid: 14907713
references.citation: J Nutr Biochem. 2001 May;12(5):254-257
references.pmid: 11382542
references.citation: Life Sci. 2006 Jan 18;78(8):803-11
references.pmid: 16253281
references.citation: Exp Gerontol. 2001 Nov;36(10):1713-26
references.pmid: 11672991
references.citation: Free Radic Biol Med. 1999 Feb;26(3-4):463-71
references.pmid: 9895239
references.citation: Int J Cardiol. 2006 Feb 8;107(1):54-60
references.pmid: 16337498
references.citation: Exp Gerontol. 2005 Mar;40(3):129-35
references.pmid: 15763389
references.citation: Neurochem Res. 1993 Nov;18(11):1157-62
references.pmid: 8255367
references.citation: J Neurochem. 1988 Aug;51(2):621-3
references.pmid: 3392549
references.citation: Methods Enzymol. 1984;105:331-7
references.pmid: 6727673
references.citation: Atherosclerosis. 2000 Jan;148(1):67-73
references.pmid: 10580172
references.citation: J Lipid Res. 1995 Nov;36(11):2383-93
references.pmid: 8656076
references.citation: Clin Chim Acta. 2006 Jun;368(1-2):84-92
references.pmid: 16480704
references.citation: J Biol Chem. 1997 Feb 7;272(6):3520-6
references.pmid: 9013599
references.citation: J Physiol Pharmacol. 2004 Sep;55(3):595-606
references.pmid: 15381830
references.citation: J Biol Chem. 1993 Jun 15;268(17):12341-7
references.pmid: 8509373
references.citation: Int J Fertil Womens Med. 2000 May-Jun;45(3):236-40
references.pmid: 10929687
references.citation: Chem Res Toxicol. 1995 Mar;8(2):284-91
references.pmid: 7766813