title: Spin-labelled lutein as a new antioxidant in protection against lipid peroxidation.
abstract: A new potentially antioxidant compound, spin-labelled lutein (SL-lut), was synthesized and incorporated into egg yolk phosphatidylcholine (EYPC) liposome membrane. The approximate location of nitroxide free radical groups of SL-lut was determined based on electron paramagnetic resonance (EPR) spectra. Then the ability of SL-lut to protect EYPC liposomes against lipid peroxidation (LPO) was compared to the antioxidant effects of lutein and a nitroxide spin label 3-carbamoyl-2,2,5,5-tetramethylpyrrolidin-1-yloxy (3-CP). Two free radical generation systems were used - a thermal decomposition of 2,2'-azobis (2,4 dimethyl-valeronitrile) (AMVN) and a modified Fenton reaction using ferric-8-hydroxyquinoline (Fe(HQ)(3)). Determination of the amount of thiobarbituric acid reactive species (TBARS) was used as a measure of LPO. SL-lut was the most powerful antioxidant, reducing LPO by about 6-times in AMVN-treated liposomes and 7-times in Fe(HQ)(3)-treated liposomes. Lutein alone gave only a moderate protection in both systems, while 3-CP was as efficient as SL-lut in the presence of AMVN, but not efficient whatsoever in the presence of Fe(HQ)(3). The results suggest that a nitroxide part of SL-lut plays an important role in enhancing the antioxidant activity of lutein and makes SL-lut a powerful antioxidant efficient under different conditions.
authors.affiliation: Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
authors.forename: Katarzyna A
authors.initials: KA
authors.lastname: Broniowska
authors.forename: Igor
authors.initials: I
authors.lastname: Kirilyuk
authors.forename: Anna
authors.initials: A
authors.lastname: Wisniewska
mesh_terms: D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D001391:Azo Compounds / Q000737:chemistry; D003497:Cyclic N-Oxides / Q000737:chemistry; D004530:Egg Yolk / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000032:analysis; D006912:Hydroxyquinolines / Q000737:chemistry; D015227:Lipid Peroxidation / Q000187:drug effects*; D008081:Liposomes / Q000737:chemistry; D014975:Lutein / Q000737:chemistry / Q000494:pharmacology; D008315:Malondialdehyde / Q000032:analysis; D008566:Membranes / Q000737:chemistry / Q000187:drug effects; D009570:Nitriles / Q000737:chemistry; D010713:Phosphatidylcholines / Q000737:chemistry; D011759:Pyrrolidines / Q000737:chemistry; D013113:Spin Labels; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
chemical_list: D000975:Antioxidants; D001391:Azo Compounds; D003497:Cyclic N-Oxides; D005609:Free Radicals; D006912:Hydroxyquinolines; D008081:Liposomes; D009570:Nitriles; D010713:Phosphatidylcholines; D011759:Pyrrolidines; D013113:Spin Labels; D017392:Thiobarbituric Acid Reactive Substances; C055792:2,2'-azobis(2,4-dimethylvaleronitrile); C077426:3-carbamoyl-2,2,5,5-tetramethyl-1-pyrrolidinyl-N-oxyl; D008315:Malondialdehyde; D014975:Lutein