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

Inhibition of the formation of beta-amyloid fibrils (fA beta), as well as the destabilization of preformed fA beta 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 fA beta formation from A beta and destabilize preformed fA beta in vitro. Using fluorescence spectroscopic analysis with thioflavin T and electron microscopic studies, we examined the effects of coenzyme Q(10) (CoQ(10)) on the formation, extension, and destabilization of fA beta at pH 7.5 at 37 degrees C in vitro. We next compared the anti-amyloidogenic activities of CoQ(10) with NDGA and Myr. CoQ(10) dose-dependently inhibited fA beta formation from amyloid beta-peptide (A beta), as well as their extension. Moreover, it destabilized preformed fA beta s. The anti-amyloidogenic effects of CoQ(10) were slightly weaker than those of NDGA and Myr. CoQ(10) could be a key molecule for the development of therapeutics for AD. (c) 2005 Elsevier Inc. All rights reserved.