title: Lysophosphatidylcholine-arbutin complexes form bilayer-like structures.
abstract: Arbutin is known to suppress melanin production in murine B16 melanoma cells and inhibit phospholipase action. This encourages the possibility to stabilize it in lipid aggregates for its administration in medical applications. Thus, it was of interest to demonstrate that monomyristoylphosphatidylcholine (14:0 lysoPC) and arbutin may form association complexes. This was studied by Electron Microscopy (EM), 31P Nuclear Magnetic Resonance (31P NMR), Electronic Paramagnetic Resonance (EPR) and Fourier Transform Infrared Spectroscopy (FTIR). EM images show the formation of particles of c.a. 6 nm in diameter. For a 1:1 lysoPC-arbutin molar ratio 31P NMR shows a spectrum with a shoulder that resembles the axially symmetric spectrum characteristic of vesicles. The addition of La3+ ions to the arbutin-lysoPC complex allows one to distinguish two phosphorous populations. These results suggest that arbutin-lysoPC forms vesicles with bilayers stabilized in an interdigitated array. FTIR spectroscopy shows that arbutin interacts with the hydrated population of the carbonyl groups and with the phosphates through the formation of hydrogen bonds. It is interpreted that hydrophobic interactions among the phenol group of arbutin and the acyl chain of lysoPC are responsible for the decrease in acyl chain mobility observed at the 5th C level by EPR. A model proposing the formation of interdigitated bilayers of arbutin-lysoPC could explain the experimental results.
authors.affiliation: Instituto de Química Física, Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Lorenzo 456 (4000) Tucumán, Argentina.
authors.forename: M A
authors.initials: MA
authors.lastname: Frías
authors.forename: B
authors.initials: B
authors.lastname: Winik
authors.forename: M B
authors.initials: MB
authors.lastname: Franzoni
authors.forename: P R
authors.initials: PR
authors.lastname: Levstein
authors.forename: A
authors.initials: A
authors.lastname: Nicastro
authors.forename: A M
authors.initials: AM
authors.lastname: Gennaro
authors.forename: S B
authors.initials: SB
authors.lastname: Diaz
authors.forename: E A
authors.initials: EA
authors.lastname: Disalvo
mesh_terms: D000818:Animals; D001104:Arbutin / Q000737:chemistry*; D045744:Cell Line, Tumor; D004578:Electron Spin Resonance Spectroscopy; D008051:Lipid Bilayers; D008244:Lysophosphatidylcholines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D046529:Microscopy, Electron, Transmission; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D008051:Lipid Bilayers; D008244:Lysophosphatidylcholines; D001104:Arbutin