3-Hydroxyquinolin-2-Ones Act as Dual Inhibitors of Ferroptosis and Monoamine Oxidase B: Reducing Alzheimer’s Disease-Related Amyloid Precursor Protein and Hyperphosphorylated Tau In Vivo

The challenges in the current treatment landscape for Alzheimer's disease (AD) underscore the urgent need for novel therapeutic strategies targeting multiple pathological pathways. Recent studies have implicated iron in ROS-dependent neuronal injury through ferroptosis. Additionally, overexpression of monoamine oxidase B (MAO-B) induces oxidative stress and decreases cognitive function. In this study, we presented the novel dual inhibitors of ferroptosis and MAO-B for AD management, aiming to address both the symptomatic and neurodegenerative aspects of this disease. Compound 21d emerged as a promising candidate, exhibiting potent and selective MAO-B inhibitory activity (IC₅₀ = 87.47 nM, SI > 229), as well as excellent antiferroptosis activity through modulation of the iron metabolic pathway and GSH-GPX4 axis in vitro. Importantly, 21d normalized cognitive and memory impairments in a 3×Tg (APP/Tau/Ps1) AD mouse model and reduced levels of AD-related proteins, including amyloid precursor protein and phosphorylated Tau protein, in the brains of AD mice.