Quercetin Encapsulated Polymer Nanoparticle for Inhibiting Intracellular Polyglutamine Aggregation.

Quercetin is a dietary flavonoid that shows effective neuroprotective action in cellular and animal models of Alzheimer's disease and Huntington's disease. However, its therapeutic application is limited due to low water solubility and cytotoxicity at the working concentration in the 20-100 μM range. Here we report a nanoparticle form of quercetin (nanoquercetin) that shows antiamyloidogenic performance at lower quercetin concentration (one micromolar) and inhibits polyglutamine (mutant huntingtin) aggregation in Huntington's disease cell model. Nanoquercetin is composed of a polyaspartic acid-based polymer micelle encapsulated with quercetin (3-5 wt %) and colloidal in nature with <100 nm hydrodynamic size. It enters into the cell via endocytosis and slowly releases molecular quercetin in a >3 day time scale that offers better antiamyloidogenic performance via up-regulated autophagy processes. This work shows that nanoformulation of antiamyloidogenic molecule can have better performance as compared to respective molecule.