Preparation and properties of fucoxanthin-loaded liposomes stabilized by sea cucumber derived cholesterol sulfate instead of cholesterol

The preparation of steady-state phospholipid liposomes requires cholesterol as a stabilizer, but excessive intake of cholesterol may increase the risk of cardiovascular disease. The sulfated sterols extracted from sea cucumber, mainly including sulfated 24-methylene cholesterol and cholesterol sulfate, have been reported to have a variety of physiological activities. Sulfated sterols are similar to cholesterol in structure and have the potential to replace cholesterol to prepare novel stable multifunctional liposomes, allowing the liposomes to act as carriers for the delivery of less bioavailable nutrients while allowing sulfated sterols in the lipid bilayer to exert physiologically active effects. This study aimed to prepare a novel multifunctional nanoliposome stabilized with sulfated sterols from sea cucumber instead of cholesterol by ultrasound-assisted thin-film dispersion method. The results showed that stable and uniformly dispersed nanoliposomes could be formed when the substitution ratio of sea cucumber-derived cholesterol sulfate was 100% and the ratio of lecithin to cholesterol sulfate was 3:1. Fucoxanthin encapsulated liposome with egg yolk lecithin/sea cucumber-derived cholesterol sulfate/fucoxanthin mass ratio of 6:2:3 was successfully prepared, with an average particle size of 214 ± 3 nm, polydispersity index (PDI) value of 0.297 ± 0.006, the zeta potential of -57.2 ± 1.10 mV, and the encapsulation efficiency of 85.5 ± 0.8%. The results of digestion and absorption in vitro and in vivo showed that liposomes could significantly improve the bioavailability of fucoxanthin and prolong its residence time in serum. As an efficient multifunctional carrier, this novel liposome has great potential for applications in functional foods and biomedicine.