In vitro screening on β-amyloid peptide production of plants used in traditional medicine for cognitive disorders

Aim of the study: The aim of the study was to investigate the activity on p-amyloid peptide production of crude extracts of 9 plant species traditionally used in Benin or in Madagascar for the treatment of cognitive disorders, in order to select candidates for Alzheimer's disease treatment. Materials and methods: For each species, hexane, dichloromethane, ethyl-acetate and water extracts were tested, at non-toxic concentrations, on CHO cells overexpressing the human neuronal P-amyloid peptide precursor (APP695) to measure variations of APP processing (by Western-blotting) and, for the most active, of A beta-amyloid production (by ECLIA). Results: We observed, at non-toxic concentrations, a significant increase in CTF/APP ratio with Oldenlandia affinis cyclotide-enriched fraction, Prosopis africana EtOAc extract, Pterocarpus erinaceus aqueous extract and Trichilia emetica hexane extract. We also showed that the Pterocarpus erinaceus extract significantly decreased A beta production, displaying effects similar to those of DAPT (gamma-secretase inhibitor) on APP processing, but may act on another inhibition site. Conclusion: These active extracts are worth further studies to isolate the compounds responsible for the observed activities, to analyze their mode of action and determine their clinical potentials. (C) 2010 Elsevier Ireland Ltd. All rights reserved.