title: The impact of humic and fulvic acids on the dynamic properties of liposome membranes: the ESR method.
abstract: This paper presents the results of research on the influence of two fractions of humic substances (HS): fulvic acids (FA) and humic acids (HA), as a function of concentration, on the liposome membranes formed from egg yolk lecithin (EYL). The concentration of HS in relation to EYL changed from 0% to 10% by weight. The influence of HS on various areas of membranes: interphase water-lipid, in the lipid layer just below the polar part of the membrane and in the middle of the lipid bilayer, was investigated by different spin labels (TEMPO, DOXYL 5, DOXYL 16). The study showed that HA slightly decreased the fluidity of the analyzed membranes on the surface layer, while FA significantly liquidated the center of the lipid bilayer. The strong effect of both fractions of HS on the concentration of free radicals as a function of time was also described.
authors.affiliation: Institute of Physics, Opole University , Opole , Poland .
authors.forename: Dariusz
authors.initials: D
authors.lastname: Man
authors.forename: Izabella
authors.initials: I
authors.lastname: Pisarek
authors.forename: Michał
authors.initials: M
authors.lastname: Braczkowski
authors.forename: Barbara
authors.initials: B
authors.lastname: Pytel
authors.forename: Ryszard
authors.initials: R
authors.lastname: Olchawa
mesh_terms: D001578:Benzopyrans / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D005609:Free Radicals / Q000032:analysis; D006812:Humic Substances; D007700:Kinetics; D008051:Lipid Bilayers; D008081:Liposomes / Q000737:chemistry*; D008560:Membrane Fluidity; D019906:Nuclear Magnetic Resonance, Biomolecular; D013113:Spin Labels
chemical_list: D001578:Benzopyrans; D005609:Free Radicals; D006812:Humic Substances; D008051:Lipid Bilayers; D008081:Liposomes; D013113:Spin Labels; C005023:fulvic acid
keywords: ESR method; EYL liposomes; humic substances