Study of the Emulsion Stability and Headgroup Motion of Phosphatidylcholine and Lysophosphatidylcholine by ¹³C- and ³¹P-NMR

Abstract

The headgroup motional properties of emulsified egg phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) were investigated by ¹³C- and ³¹P-NMR. PC, LPC and their equimolar mixture were emulsified in water and n-decane under varied pH conditions. The line width of phosphorus and T^*₂ relaxation time of the choline and glycerol carbons depended on the aqueous phase conditions, and were correlated with the emulsion stability. In stable emulsions, the choline and phosphate residue of PC or LPC had motional freedom; however, the glycerol residue was moderately restricted. It is presumed that the motion of part of the headgroup played an important role in the formation of a stable emulsion. Thus, the control of headgroup motion is regarded as one way to obtain stable emulsions.