Preformed β-amyloid fibrils are destabilized by coenzyme Q10 in vitro

Inhibition of the formation of β-amyloid fibrils (fAβ), as well as the destabilization of preformed fAβ in the CNS, would be attractive therapeutic targets for the treatment of Alzheimer's disease (AD). We reported previously that nordihydroguaiaretic acid (NDGA) and wine-related polyphenol, myricetin (Myr), inhibit fAβ formation from Aβ and destabilize preformed fAβ in vitro. Using fluorescence spectroscopic analysis with thioflavin T and electron microscopic studies, we examined the effects of coenzyme Q10 (CoQ10) on the formation, extension, and destabilization of fAβ at pH 7.5 at 37 °C in vitro. We next compared the anti-amyloidogenic activities of CoQ10 with NDGA and Myr. CoQ10 dose-dependently inhibited fAβ formation from amyloid β-peptide (Aβ), as well as their extension. Moreover, it destabilized preformed fAβs. The anti-amyloidogenic effects of CoQ10 were slightly weaker than those of NDGA and Myr. CoQ10 could be a key molecule for the development of therapeutics for AD.