Effects of <i>β</i>-Sitosteryl Sulfate on the Hydration Behavior of Dipalmitoylphosphatidylcholine

Abstract

We investigated the hydration behavior of dipalmitoylphosphatidylcholine (DPPC) bilayers containing sodium β-sitosteryl sulfate (PSO). PSO was found to enhance hydration in the headgroup region of DPPC bilayers. Therefore, with the incorporation of PSO into DPPC membranes, the amount of water required to reach the fully hydrated state was enhanced as indicated by the constant values of the main phase transition temperature (T) and the bilayer repeat distance (d). For example, with the addition of 20 mol% of PSO, the saturation point was shifted to ~70 wt% water compared to ~40 wt% for pure DPPC and 47 wt% for DPPC-cholesterol. The effectiveness of PSO in fluidizing the membrane and enhancing its hydration state can be useful in the pharmaceutical and cosmetic industries.

Effects of β-Sitosteryl Sulfate on the Properties of DPPC Liposomes

“…A similar effect of the enhanced hydration has been reported previously by Mohapatra and Mishra 20 in DPPC membranes containing bile salt. This enhancement of hydration of DPPC by PSO 4 is also consistent with our previous reports 8,9 . For the sonicated samples, a comparable tendency was observed data not shown but the r value was very low; this could be due to poor incorporation of the probe in the bilayer because of the extremely small sizes of the liposomes and their high curvature.…”

Phase Behavior of the Bilayers Containing Hydrogenated Soy Lecithin and β-Sitosteryl Sulfate

“…22,27,28 PSO 4 has a significant hydration effect on the membrane. 30 Additionally, in combination with a saturated PC, PSO 4 also forms small-sized multilamellar vesicles (MLVs) of higher stabilities. 4,30 Thus, a PC−PSO 4 mixture may be appropriate for preparing cosmetic and pharmaceutical formulations.…”

“…30 Additionally, in combination with a saturated PC, PSO 4 also forms small-sized multilamellar vesicles (MLVs) of higher stabilities. 4,30 Thus, a PC−PSO 4 mixture may be appropriate for preparing cosmetic and pharmaceutical formulations. Furthermore, the high cost associated with the use of pure, saturated PCs prevents their use in many commercial products.…”

“…In our previous studies, we reported the effects of β-sitosteryl sulfate (PSO 4 ) (Figure ) on the phase behavior and membrane properties of pure DPPC and DSPC. ,, PSO 4 , being plant-derived, is a good alternative to cholesterol since the use of the latter is associated with infections such as bovine spongiform encephalopathy (BSE) . In those studies, we found that even small quantities of β-sitosteryl sulfate (PSO 4 ) disorders the PC hydrocarbon chains and converts the membrane into a mixture of sterol-rich and sterol-poor domains. ,, PSO 4 has a significant hydration effect on the membrane . Additionally, in combination with a saturated PC, PSO 4 also forms small-sized multilamellar vesicles (MLVs) of higher stabilities. , Thus, a PC–PSO 4 mixture may be appropriate for preparing cosmetic and pharmaceutical formulations.…”

“…In those studies, we found that even small quantities of β-sitosteryl sulfate (PSO 4 ) disorders the PC hydrocarbon chains and converts the membrane into a mixture of sterol-rich and sterol-poor domains. ,, PSO 4 has a significant hydration effect on the membrane . Additionally, in combination with a saturated PC, PSO 4 also forms small-sized multilamellar vesicles (MLVs) of higher stabilities. , Thus, a PC–PSO 4 mixture may be appropriate for preparing cosmetic and pharmaceutical formulations. Furthermore, the high cost associated with the use of pure, saturated PCs prevents their use in many commercial products.…”