Investigating the Potency of Erythrina‒Derived Flavonoids as Cholinesterase Inhibitors and Free Radical Scavengers Through in silico Approach: Implications for Alzheimer's Disease Therapy.

Purpose: This study aimed to evaluate the potency of 471 flavonoids from the genus Erythrina as potential acetylcholinesterase (AChE) inhibitors and free radical scavengers through computational studies to develop Alzheimer's disease (AD) therapies from natural products.

Methods: A total of 471 flavonoids from the genus Erythrina were subjected to molecular docking against AChE, followed by toxicity screening. The potential AChE inhibitors with the least toxic profile were subjected to further investigation through molecular dynamics (MD) simulations, density functional theory (DFT) study, and in silico pharmacokinetic predictions.

Results: A combination of molecular docking and in silico toxicity screening led to the identification of 2(S)‒5,7‒dihydroxy‒5'‒methoxy‒[2'',2''‒(3''‒hydroxy)‒dimethylpyrano]‒(5'',6'':3',4') flavanone (89) and Abyssinoflavanone IV (83) as potential AChE inhibitors. These compounds had stable binding to AchE and exhibited lower Root Mean Square Deviation (RMSD) values compared to the apo state of AChE. In addition, Molecular Mechanics Generalized Born Surface Area (MMGBSA) analysis revealed that the binding energies of 89 and 83 were significantly lower compared to acetylcholine, the natural substrate of AChE. Based on DFT study, these compounds exhibited a higher energy in the highest occupied molecular orbital (E_HOMO) and lower electron affinity (EA) than Quercetin. This indicated that 89 and 83 could be potential radical scavengers through their electron-donating activity.

Conclusion: Although this study primarily relied on computational methods, the results showed the dual functionality of compounds 89 and 83 as both potential AChE inhibitors and free radical scavengers. Further investigation in wet laboratory experiments is required to validate their therapeutic potential for AD.