Effects of Chrysanthemum coronarium L. on the Thermotropic Behavior of DPPC Liposomal Membrane

To understand the effects of the fraction from Chrysanthemum coronarium L. (CC), we prepared five different types of samples, denoted here as CCMM, CCMH, CCMEA, CCMB and CCMA. We studied the effects of these samples on the phase transition of liposomal membranes by high-sensitivity differential scanning calorimetry (nano-DSC). We used dipalmitoylphosphatidylcholine (DPPC) bilayers which make most stable liposomes among the other phosphatidylcholines. When the samples were added to the bilayers, the phase transition temperatures of DPPC liposomes incorporated with CCMH and CCMEA were decreased by 1.5 and 2^{\circ}C$, while the other three fractions showed less tendencies. The CCMH and CCMEA fractions markedly affected the thermotropic properties of DPPC liposomes, broadened and shifted the thermograms of DSC. It also significantly reduced the size of cooperative unit of the transition. In all cases, there was no change in enthalpy of transition within the concentration range of the CC fractions studied. We concluded that the incorporation of the CCMH and CCMEA into DPPC liposomes was preferentially located in the hydrophobic core of DPPC bilayers compared to the other three fractions CCMM, CCMB and CCMA. These results suggest that certain substances in CCMH and CCMEA fractions might have biologically significant effects on the fluidity of biological membrane.