Studies on phytosterol acetate esters and phytosterols liposomes

Abstract

Phytosterols (PS) and phytosterol esters have been widely used in the food and health product industries as cholesterol-lowering agents. In order to improve theirs dispersity and bioavailability in low lipid media, PS and phytosterol acetate ester (PAE) were embedded into liposomes in the study. The effects of different PAE or PS concentrations on liposome properties were determined and interactions between PAE or PS and phospholipids were also explored. PAE and PS can be well embedded in liposomes, and the encapsulation rate was more than 90%. Compared to SPC liposomes, no significant difference (P > 0.05) in particle size (60 nm) and zeta potential (-15 mV) were observed between liposomes with PAE or PS. Liposomes were spherical, with smooth surfaces and uniform size distributions. The results of X-ray powder diffractometry (XRD) revealed that PAE and PS were amorphously embedded in liposomes. The results from the Fourier-transform infrared (FTIR) and Differential scanning calorimeter (DSC) analysis indicated that PAE or PS changed the structure of the lipid membrane by interacting with phospholipids in the liposomes. Low doses of PAE had a stabilizing effect on the liposome membrane structure.

Keywords:
phytosterol acetate esters; phytosterols; liposome; effect; properties