Structural properties of paeonol encapsulated liposomes at physiological temperature: Synchrotron small-angle and wide-angle X-ray diffraction studies

Structural properties of paeonol-encapsulated liposomes containing cholesterol or stigmasterol at 37°C have been investigated by synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) techniques. We compared the structural properties of pure dipalmitoylphosphatidylcholine (DPPC) liposomes, sterol–DPPC liposomes, and those of paeonol–sterol–DPPC liposomes at different molar ratios. Three conclusions can be drawn: First, phase separation occurs in both sterol–DPPC and paeonol–sterol–DPPC liposomes. Second, the incorporation of paeonol molecules into sterol– DPPC liposomes weakens the membrane order. Third, cholesterol has a stronger tendency to interact with DPPC as compared to its counterpart in plant, stigmasterol.