title: An inelastic neutron scattering study of dietary phenolic acids.
abstract: The conformational preferences and hydrogen-bonding motifs of several potential chemopreventive hydroxycinnamic derivatives were determined by inelastic neutron scattering spectroscopy. The aim is to understand their recognized beneficial activity and establish reliable structure-activity relationships for these types of dietary phytochemicals. A series of phenolic acids with different hydroxyl/methoxyl ring substitution patterns were studied: trans-cinnamic, p-coumaric, m-coumaric, trans-caffeic and ferulic acids. Their INS spectra were completely assigned by theoretical calculations performed at the Density Functional Theory level, for the isolated molecule, dimeric centrosymmetric species and the solid (using plane-wave expansion approaches). Access to the low energy vibrational region of the spectra enabled the identification of particular modes associated with intermolecular hydrogen-bonding interactions, which are the determinants of the main conformational preferences and antioxidant capacity of these systems.
authors.affiliation: Research Unit "Molecular Physical Chemistry", Faculty of Science and Technology, University of Coimbra, 3004-535 Coimbra, Portugal.
authors.forename: M Paula M
authors.initials: MP
authors.lastname: Marques
authors.forename: Luís A E
authors.initials: LA
authors.lastname: Batista de Carvalho
authors.forename: Rosendo
authors.initials: R
authors.lastname: Valero
authors.forename: Nelson F L
authors.initials: NF
authors.lastname: Machado
authors.forename: Stewart F
authors.initials: SF
authors.lastname: Parker
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D006860:Hydrogen Bonding; D062385:Hydroxybenzoates / Q000737:chemistry*; D033363:Neutron Diffraction; D011789:Quantum Theory
chemical_list: D000975:Antioxidants; D062385:Hydroxybenzoates; C017616:phenolic acid