Preformed oligomers and fibril remodeling activity of K-3-rh. A. Th-T assay of fresh monomeric Aβ42 as control (white bar), Aβ42 preformed oligomers (gray bar) and Aβ42 preformed oligomers in the presence of 40 μM K-3-rh (black bar) incubated for 0, 12 and 24 h. B. TEM study of maturation of Aβ42 preformed oligomers (OAβ) in the absence (left and middle panel) or presence of 40 μM of K-3-rh (right panel). C. Dissolution of preformed Aβ42 fibrils in the presence of different concentrations of K-3-rh. The mature Aβ42 fibrils (20 μM) were incubated in the absence or presence of 0, 10, 20, 40 and 50 μM of K-3-rh for 6 h. IC50 for fibrils disintegration was found to be > 40 μM. Error bars indicate the standard deviation of triplicate independent experiments. D. TEM study of fibril disaggregation properties of K-3-rh. Twenty μM fibrillar Aβ42 (fAβ) was incubated in the absence or presence of 20 and 40 μM of K-3-rh for 12 h and TEM images were obtained. Scale bar is shown at the bottom. E. Cells were treated with 20 μM of oligomeric (gray bar) or fibrilar (black bar) Aβ42 for 12 h in the absence or presence of 0–50 μM of K-3-rh. Cell viability was assessed by the MTT reduction assay. Error bars indicate the standard deviation of triplicate independent experiments. Significantly different from only Aβ42 or 0 flavonoid concentration group indicated as **p < 0.01 for oligomers Aβ and ## p < 0.01 for fibrilar Aβ.