Lysophosphatidylcholine–arbutin complexes form bilayer-like structures

M. A. FRÍAS , B. WINIK, M. B. FRANZONI, P. R. LEVSTEIN , A. NICASTRO , A. M. GENNARO, S. B. DIAZ, E. A. DISALVO

BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES

Año: 2008 vol. 1778 p. 1259 - 1266

0005-2736

Arbutin is known to suppress melanin production in murine B16 melanoma cells and inhibit phospholipase action. This encourages the possibilityto 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 MagneticResonance (31P NMR), Electronic Paramagnetic Resonance (EPR) and Fourier Transform Infrared Spectroscopy (FTIR). EM images show theformation 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 theaxially symmetric spectrum characteristic of vesicles. The addition of La3+ ions to the arbutin–lysoPC complex allows one to distinguish twophosphorous populations. These results suggest that arbutin–lysoPC forms vesicles with bilayers stabilized in an interdigitated array. FTIRspectroscopy shows that arbutin interacts with the hydrated population of the carbonyl groups and with the phosphates through the formation ofhydrogen bonds. It is interpreted that hydrophobic interactions among the phenol group of arbutin and the acyl chain of lysoPC are responsible for thedecrease in acyl chain mobility observed at the 5th C level by EPR. A model proposing the formation of interdigitated bilayers of arbutin-lysoPCcould explain the experimental results.