Effect of Flavonoids on the Phase Separation in Giant Unilamellar Vesicles Formed from Binary Lipid Mixtures

Confocal fluorescence microscopy have been employed to investigate phase separation in giant unilamellar vesicles prepared from binary mixtures of unsaturated dioleoylphosphocholine with saturated phosphocholines or brain sphingomyelin in the absence and presence of the flavonoids, biochanin A, phloretin, and myricetin. It has been demonstrated that biochanin A and phloretin make uncolored domains more circular or eliminate visible phase separation in liposomes while myricetin remains the irregular shape of fluorescence probe-excluding domains. Influence of the flavonoids on the endotherms of liposome suspension composed of dioleoylphosphocholine and dimyristoylphosphocholine was investigated by the differential scanning calorimetry. Calorimetry data do not contradict to confocal imaging results.