title: Influence of lipids with hydroxyl-containing head groups on Fe2+ (Cu2+)/H2O2-mediated transformation of phospholipids in model membranes.
abstract: Under condition of ROS formation in lipid membranes, free radical reactions can proceed in both hydrophobic (peroxidation of lipids, POL) and polar (free radical fragmentation) parts of the bilayer. Free-radical fragmentation is typical for the lipids containing a hydroxyl group in β-position with respect to an ester or amide bond. The present study has been undertaken to investigate free-radical transformations of phospholipids in model membranes containing lipids able to undergo fragmentation in their polar part. Liposomes from egg yolk lecithin containing saturated or monounsaturated glycero- and sphingolipids were subjected to the action of an HO* - generating system - Fe(2+)(Cu(2+))/H2O2/Asc, and the POL products were investigated. In parallel with this, the effects of monoacylglycerols and scavengers of reactive species on Fe(2+)(Cu(2+))/H2O2/Asc - mediated free-radical fragmentation of phosphatidylglycerols were studied. Hydroxyl-containing sphingolipids and glycerolipids, which undergo free-radical fragmentation under such conditions, manifested antioxidant properties in the model membranes. In the absence of HO groups in the lipid structure, the effect was either pro-oxidant or neutral. Monoacylglycerols slowed down the rate of both peroxidation in the hydrophobic part and free-radical fragmentation in the hydrophilic part of phospholipid membrane. Scavengers of reactive species inhibited the fragmentation of phosphatidylglycerol substantially. Thus, the ability of hydroxyl-containing lipids to undergo free-radical fragmentation in polar part apparently makes a substantial contribution to the mechanism of their protector action.
authors.affiliation: Department of Chemistry, Belarusian State University, Minsk, Belarus.
authors.forename: Viktoriya N
authors.initials: VN
authors.lastname: Olshyk
authors.affiliation: Department of Chemistry, Belarusian State University, Minsk, Belarus.
authors.forename: Inna V
authors.initials: IV
authors.lastname: Melsitova
authors.affiliation: Department of Chemistry, Belarusian State University, Minsk, Belarus; Research Institute for Physical Chemical Problems of the Belarusian State University, Minsk, Belarus. Electronic address: yurkovail@tut.by.
authors.forename: Irina L
authors.initials: IL
authors.lastname: Yurkova
mesh_terms: D003300:Copper / Q000378:metabolism*; D020404:Glycerophospholipids / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D017665:Hydroxyl Radical / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D015227:Lipid Peroxidation; D008081:Liposomes / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D020404:Glycerophospholipids; D008081:Liposomes; D010713:Phosphatidylcholines; D010743:Phospholipids; D017665:Hydroxyl Radical; D003300:Copper; D006861:Hydrogen Peroxide; D007501:Iron
keywords: Copper; Free-radical fragmentation; Lipid peroxidation; Phospholipids; Reactive oxygen species; Sphingolipids