Multifunctional thioxanthone derivatives with acetylcholinesterase, monoamine oxidases and β-amyloid aggregation inhibitory activities as potential agents against Alzheimer's disease.

A series of 1-hydroxyl-3-aminoalkoxy-thioxanthone derivatives were designed, synthesized and evaluated as potential multifunctional agents against Alzheimer's disease (AD). The results indicated that most of these compounds exhibited good AChE and MAOs inhibitory activities, significant inhibition of self- and Cu ²⁺ -induced Aβ _1-42 aggregation, and moderate to good antioxidant activities. Specifically, compound 9e displayed high inhibitory potency toward AChE (IC ₅₀ =0.59±0.02μM), MAO-A and MAO-B (IC ₅₀ =1.01±0.02μM and 0.90±0.01μM respectively), excellent efficiency to block both self- and Cu ²⁺ -induced Aβ _1-42 aggregation (74.8±1.2% and 87.7±1.9% at 25μM, respectively), good metal-chelating property and a low toxicity in SH-SY5Y cells. Furthermore, kinetic and molecular modeling studies revealed that compound 9e binds simultaneously to the catalytic active site and peripheral anionic site of AChE, and could penetrate the BBB. Collectively, these results suggested that 9e might be a potential multifunctional agent for further development in the treatment of AD.
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