Synthesis, structure, and thermal properties of 1,2-dipalmitoylgalloylglycerol (DPGG), a novel self-adhering lipid

A novel diacyl glycerol-based lipid with a polyphenolic head group has been synthesized and characterized. X-ray diffraction experiments show that thi s lipid, 1,2-dipalmitoylgalloylglycerol (DPGG), hydrates to form gel phase bilayers at 20 degrees C with extremely narrow interbilayer fluid separatio ns, indicating that apposing DPGG bilayers strongly adhere to each other. D ifferential scanning calorimetry shows that fully hydrated DPGG exhibits a pretransition exotherm (3.7 kcal/mol) at 52 degrees C and a high enthalpy ( 11.3 kcal/mol) main endothermic transition at 69 degrees C. These thermal p roperties are similar to those of galactosylceramides with similar hydrocar bon chain compositions. The adhesive and thermal properties of DPGG are lik ely due to both intermolecular hydrogen-bonding and hydrophobic interaction s between the aromatic rings on the gallic acids. (C) 2000 Published by Els evier Science Ireland Ltd. All rights reserved.