Preparation, stability and antioxidant capacity of nano liposomes loaded with procyandins from lychee pericarp

Oligomeric procyanidins (OPC) from lychee pericarp were encapsulated in liposomes using the film dispersion method, and their physicochemical and structural properties, stability and antioxidant activity were determined. Results indicated that liposomes prepared under a 1:15 cholesterol to yolk lecithin ratio, 1:30 OPC to lecithin and 15 g/L Tween-80 generated particles with a size range of 80-100 nm. The highest encapsulation efficiency (90.92 +/- 0.47%) was achieved when the OPC load rate was 2%. The liposomes were spherical vesicles, as seen under transmission electron microscopy, and were stable at 4 degrees C. Metal ions and preservatives at a concentration of 0.5% (m:v) had no significant effect on the particle size and zeta-potential. The encapsulation by a phospholipid bilayer effectively reduced the loss of antioxidant activity of OPC during storage. The ferric ion reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and cellular antioxidant activity (CAA) values of individual OPC decreased by 3.32-35.22%, 20.10-38.08% and 43.56%, respectively, while for OPC-liposomes, these values decreased by 2.75-22.40%, 6.06-17.92% and 12.86%. These results suggest that liposomes offer a feasible option for stabilizing lychee pericarp procyanidins.