Phytochemical profiling and in vitro evaluation of the BACE1 inhibitory potential of Hyraceum stone methanol extract

Abstract

Plant secondary metabolites are an important source of structurally diverse bioactive compounds with potential pharmacological significance. Hyraceum stone (HS), a fossilized excreta-derived material from the rock hyrax ( Procavia capensis ), has been traditionally used for the management of neurological disorders. Despite its ethnomedicinal use, the chemical composition and potential relevance of HS in the context of Alzheimer’s disease (AD) remain largely unexplored. β-Site amyloid precursor protein cleaving enzyme (BACE1) is a key enzyme involved in amyloid-β production and represents an important therapeutic target in AD. In this study, the phytochemical profile of a methanolic extract of HS (HS-MeOH) was characterised using liquid chromatography–mass spectrometry (LC-MS), and its BACE1 inhibitory activity and cytotoxicity profile were evaluated. Molecular docking analysis was used to explore the potential interactions of selected putatively identified constituents with the BACE1 active site, with myricetin and chlorogenic acid demonstrating favourable predicted binding interactions. In a fluorescence resonance energy transfer (FRET)-based enzymatic assay, HS-MeOH exhibited moderate concentration-dependent inhibition of BACE1 activity (IC 50 = 49.50 ± 6.58 µg/mL). Cytotoxicity assessment using a WST-1 assay indicated no significant reduction in viability of Neuro-2a wild-type (N2aWT) cells at concentrations tested. Collectively, these findings suggest that HS-MeOH contains constituents with potential BACE1 inhibitory activity and warrant further investigation through bioassay-guided fractionation, compound isolation, and validation in more advanced cellular and in vivo models relevant to AD.