title: Probing the position of resveratrol in lipid bilayers: A neutron reflectivity study.
abstract: The effect of the natural antioxidant resveratrol on the structure of solid supported di-palmitoyl-phosphatidyl-choline (DPPC) bilayers in their fluid state was investigated by neutron reflectometry. Results reveal an accumulation of resveratrol (up to 25%, mol/mol) inside the headgroups and they exclude its presence in the hydrophobic core. The presence of resveratrol induces an increase of the average thickness and of the interfacial roughness of the headgroup layer. This may be due to a change of the tilt angle of the phosphocholine headgroups residing next to the resveratrol to a more upright orientation and leading to a reduction of the projected area per headgroup. This effect is propagated into the hydrophobic core, where the chain packing is modified despite the absence of resveratrol. When interacting with a DPPC/cholesterol membrane, resveratrol has a similar effect on the neighboring PC headgroups as in the cholesterol free membrane. The almost precise 1:1 insertion ratio (resveratrol:cholesterol) suggests that resveratrol is most probably inserted on top of the hydroxyl group of the cholesterol in between the PC headgroups. The ordering effect of cholesterol on the hydrophobic core is absent when both cholesterol and resveratrol are present. Most probably, the interaction of resveratrol with lipid membranes is non-specific.
authors.affiliation: Institut Laue-Langevin, 71 Avenue des Martyrs, BP 156, 38000 Grenoble, France; Departement de Physique, Faculté des Sciences, Université Libre de Bruxelles, Bd du Triomphe CP223, 1050 Bruxelles, Belgium.
authors.forename: Alexis
authors.initials: A
authors.lastname: de Ghellinck
authors.affiliation: Department of Physics, Chemistry and Pharmacy & MEMPHYS - Center for Biomembrane Physics, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
authors.forename: Chen
authors.initials: C
authors.lastname: Shen
authors.affiliation: Institut Laue-Langevin, 71 Avenue des Martyrs, BP 156, 38000 Grenoble, France.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Fragneto
authors.affiliation: Department of Physics, Chemistry and Pharmacy & MEMPHYS - Center for Biomembrane Physics, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark. Electronic address: kloesgen@sdu.dk.
authors.forename: Beate
authors.initials: B
authors.lastname: Klösgen
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D002784:Cholesterol / Q000737:chemistry; D008051:Lipid Bilayers; D009502:Neutrons; D000077185:Resveratrol; D013267:Stilbenes / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D008051:Lipid Bilayers; D013267:Stilbenes; D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol; D000077185:Resveratrol
keywords: Cholesterol; DPPC model membrane; Membrane dynamics; Membrane structure; Neutron reflectometry; Resveratrol