-Chalcone Plus Baicalein Synergistically Reduce Intracellular Amyloid Beta (Aβ) and Protect from Aβ Induced Oxidative Damage in Yeast Models of Alzheimer's Disease.

Finding an effective therapeutic to prevent or cure AD has been difficult due to the complexity of the brain and limited experimental models. This study utilized unmodified and genetically modified as model organisms to find potential natural bioactive compounds capable of reducing intracellular amyloid beta 42 (Aβ) and associated oxidative damage. Eleven natural bioactive compounds including mangiferin, quercetin, rutin, resveratrol, epigallocatechin gallate (EGCG), urolithin A, oleuropein, rosmarinic acid, salvianolic acid B, baicalein and -chalcone were screened for their ability to reduce intracellular green fluorescent protein tagged Aβ (GFP-Aβ) levels. The two most effective compounds from the screens were combined in varying concentrations of each to study the combined capacity to reduce GFP-Aβ. The most effective combinations were examined for their effect on growth rate, turnover of native Aβ and reactive oxygen species (ROS). The bioactive compounds except mangiferin and urolithin A significantly reduced intracellular GFP-Aβ levels. Baicalein and -chalcone were the most effective compounds among those that were screened. The combination of baicalein and -chalcone synergistically reduced GFP-Aβ levels. A combination of 15 μM -chalcone and 8 μM baicalein was found to be the most synergistic combination. The combination of the two compounds significantly reduced ROS and Aβ levels in yeast cells expressing native Aβ without affecting growth of the cells. These findings suggest that the combination of baicalein and -chalcone could be a promising multifactorial therapeutic strategy to cure or prevent AD. However, further studies are recommended to look for similar cytoprotective activity in humans and to find an optimal dosage.