DSC and NMR spectroscopic studies of the interaction between camphorated phenol and phospholipid liposomes

To clarify the interaction mechanism of biological activities induced by camphorated phenol (CP), the interactions between CP and phospholipid liposomes [dipalmitoyl phosphatidylcholine (DPPC) liposomes, dimyristoyl phosphatidylcholine (DMPC) liposomes and DMPC/dilauloyl phosphatidylethanolamine (DLEA) liposomes] were studies by DSC and NMR spectroscopy. CP exhibited a larger DSC phase transition properties [shift of phase transition temperature to a lower temperature and decrease in Height/Half-Height Width (H/HHW) of DSC peak)] than phenol in the various liposome systems. It was concluded from the NMR studies that CP is highly incorporated into the DPPC bilayer, the 1H and 13C signals of phenol in a complex between phenol and camphor being markedly broadened but shielded in the presence of DPPC liposomes. It was clear that CP is incorporated as a complex into the lipid bilayers.