AFM and fluorescence spectrascopy investigation for disaggregation of existing Aβ fibrils by baicalein

The wavelength for the peak of fluorescence emission of thioflavin T (ThT) was changed from 445 nm to 481 nm when ThT was added in Aβ solution which indicating the β-sheet structure of Aβ fibril. The significant decrease in the intensity of fluorescence at 481 nm was observed when the baicalein was added in mixed solution of Aβ and ThT, suggesting that the depolymerization of Aβ fibrils happened and there were Aβ fibrils left to react with ThT to keep the initial fluorescence intensity. And the existing Aβ fibrils are disaggregated by baicalein in a time- and dose-dependent manner. AFM images of the morphologies of the Aβ1–42 fibrils obviously changed smaller and more dispersive when baicalein added indicating also the depolymerization of Aβ. The results demonstrate a basis for development of a potential herb drug candidate for the treatment of Alzheimer's disease (AD).