Rapid Identification of Bioactive Compounds Reducing the Production of Amyloid β-Peptide (Aβ) from South African Plants Using an Automated HPLC/SPE/HPLC Coupling System

Abstract

Automated HPLC/SPE/HPLC coupling experiments using the Sepbox system allowed the rapid identification of four bioactive principles reducing the production of amyloid <TEX>$\beta$</TEX>-peptide (<TEX>$A{\beta}$</TEX>) from two South African plants, Euclea crispa subsp. crispa and Crinum macowanii. The structures of biologically active compounds isolated from the methanol extract of Euclea crispa subsp. crispa were assigned as 3-oxo-oleanolic acid (1) and natalenone (2) based on their NMR and MS data, while lycorine (3) and hamayne (4) were isolated from the dichloromethane-methanol (1:1) extract of Crinum macowanii. These compounds were shown to inhibit the production of <TEX>$A{\beta}$</TEX> from HeLa cells stably expressing Swedish mutant form of amyloid precursor protein (APPsw).