The Interaction of Baicalein with Dipalmitoylphosphatidylcholine Liposomes: Differential Scanning Calorimetry, Synchrotron X-ray Diffraction, and Fourier Transform Infrared Studies

Baicalein is an important flavonoid compound extracted from the roots of Scutellaria baicalensis. The interaction between baicalein and DPPC liposomes has been studied by differential scanning calorimetry, synchrotron X-ray diffraction and Fourier transform infrared spectroscopy. The results showed the phase states of liposomes change under the disturbance of baicalein. When the molar percentage of baicalein (x) is not more than 5%, the baicalein molecules promote the hydration degree of the head groups. At x=5%, the liposomes undergo a change from L-beta' to L-beta phase. When x is between 5% and 10%, the liposomes are in P-beta' phase. When x is more than 10%, the baicalein molecules alter the hydration state of head groups. Meanwhile, the phase states shift from P-beta' to P-beta. This study is of great significance to further study the interaction between drugs and biomimetic membranes and to further investigate the phase transition mechanisms of DPPC liposome.