In silico and in vitro assessment of the anti-β-amyloid aggregation and anti-cholinesterase activities of Ptaeroxylon obliquum and Bauhinia bowkeri extracts

Abstract

BACKGROUND : Alzheimer’s disease (AD) is the most common form of dementia and dementia constitutes the fifth leading cause of mortality across the globe. Available treatment modalities and drugs have abysmally failed to curtail AD. This study evaluated the mitigation of Aβ aggregation and anti-cholinesterase activities with the crude extracts of Ptaeroxylon obliquum and Bauhinia bowkeri. Computational studies of the most abundant phytochemicals from the crude extracts of both plants with proteins were investigated. The phytochemical composition of the different crude extracts (hexane, DCM, and ethanol) of the plants were analyzed with FTIR and GC-MS. The inhibitory potential of the extracts on BACE-1 and cholinesterase activities was determined with both computational molecular docking studies and in vitro enzyme assays. Their anti-aggregation properties were confirmed with Thioflavin-T assay and TEM. RESULTS : The in silico studies revealed that though thunbergol and cyclotetradecatriene (the major constituents of the extracts) inhibited all the proteins, the latter exhibited the best inhibitory potential. The in vitro results showed that while the dichloromethane (DCM) extract of P. obliquum had the highest butyrylcholinesterase (BuChE) inhibitory activity (1.77 µg/ml), the hexane and ethanol extract of B. bowkeri exhibited the highest β-site amyloid precursor cleaving enzymes-1 (BACE-1) (30.4 µg/ml) and acetylcholinesterase (AChE) (58.11 µg/ml) inhibitory efficacy, respectively. The ethanol extract (160 μg/ml) of B. bowkeri had the most efficacious anti-aggregation activity. CONCLUSIONS : This study suggests that the plants could possess neuroprotective effects and could also be sources of anti-AD novel drugs.