Extracts from Chinese herbs with anti-amyloid and neuroprotective activities.

Many Chinese herbs are well known for their neuroprotective and anti-oxidant properties. Extracts of Salvia miltiorrhiza and Anemarrhenae asphodeloides, tanshinone IIA (tanIIA), salvianolic acid B (Sal B) and sarsasapogenin (ML-1), were selected to study their dissociation potential towards Aβ42 peptide fibrils and neuroprotective effect on cells. Moreover, derivatives of sarsasapogenin (ML-2, ML-3 and ML-4) have been prepared by the addition of modified carbamate moiety. TanIIA and Sal B have shown to possess a strong ability to dissociate Aβ42 fibrils. The dissociation potential of ML-1 increased upon the introduction of carbamate moiety with N-heterocycles. In silico data revealed that derivatives ML-4 and Sal B interact with Aβ42 regions responsible for fibril stabilization through hydrogen bonds. Contrary, tanIIA binds close to a central hydrophobic region, which may lead to destabilization of fibrils. Sarsasapogenin derivative ML-2 decreased nitride oxide production, and derivative ML-4 enhanced the growth of neurites. The reported data highlight the possibility of using active compounds to design novel treatment agents for Alzheimer's disease.