X-ray and fluorescence studies on phospholipid bilayers. IX. Interactions with pentachlorophenol.

Pentachlorophenol (PCP) is a widely used and highly toxic fungicide. Its toxicity is mainly expressed at the cell membrane level. It is, therefore, of interest to test its ability to alter the lipid bilayer organization. The present study was performed by X-ray diffraction techniques on dimyristoylphosphatidylethanolamine (DMPE) and dimyristoylphosphatidylcholine (DMPC) bilayers and by fluorescence on DMPC liposomes. These two phospholipids are respectively found at the inner and outer monolayers of human erythrocyte membranes. Each type of phospholipid was made to interact with different concentrations of the sodium form of PCP in absence and in presence of water. It was found that PCP significantly affected the structure of both phospholipids, being the damage much higher in DMPC bilayers.