Аннотация:Amyloid β oligomers are the predominant toxic species in the pathology of Alzheimer’s disease. It is believed the prevailing mechanism for toxicity by amyloid oligomers includes ionic homeostasis destabilization in neuronal cells by forming ion channels (Arispe et al., PNAS, 1993). These selective, voltage-dependent, ion-permeable channel structures have been frequently studied using the model lipid membrane. We used planar lipid bilayer formed by monolayer-opposition technique and liposomes prepared by extrusing or the electroformation methods. Our results indicate that the channel forming activity of fragments 25-35 of β-amyloid peptide signicant by increase at the addition of phloretin to membrane bathing solution. The results obtained by electron microscopy have demonstrated that the negatively charged dipole modifier interacts with positively charged fragments 25-35 of β-amyloid peptide and influences on peptide oligomerization. We found that time course of β-amyloid induced leakage of calcein from liposomes is characterized by two components: the fast one is related to sorption of peptide on the membrane and the slow one is related to the oligomerization of the peptides on the lipid bilayer surface. The introduction of the phloretin simultaneously with β-amyloid peptide into the suspension of liposomes leads to significant reduction in times characterizing fast and slow components. We also demonstrated that the introduction of fragment 25-35 of β-amyloid peptide to the suspension of liposomes caused amplification of phase segregation in the liposome membranes and 90 % vesicles contained solid ordered domains. Addition of the phloretin to the liposomes modified by amyloid leads to disrupting the gel domains. We concluded that phloretin compensates the positive charge of the amyloid peptides and leads to the changes in their oligomerization status.