Mangifera indica 'Namdokmai' Prevents Neuronal Cells from Amyloid Peptide Toxicity and Inhibits BACE-1 Activities in a Drosophila Model of Alzheimer's Amyloidosis

Alzheimer's disease (AD) is a progressive neurological illness with few effective treatments. Thus, ameliorating the effects of AD using natural products has attracted global attention with promising efficacy and safety. In this study, ten tropical fruits including 'Phulae', 'Pattavia', 'Khaekdum', 'Khaeknuan', 'Monthong', 'Chanee', 'Kimju', 'Keenok', 'Kaew' and 'Namdokmai' were screened for their inhibitory activities against the key enzymes, cholinesterases and β-secretase (BACE-1), involved in AD pathogenesis. The top three fruit extracts with promising in vitro anti-AD activities were further investigated using rat pheochromocytoma PC-12 neuronal cell line and AD model. Data showed that 'Kaew', 'Namdokmai' and 'Kimju' reduced Aβ -mediated neurotoxicity by promoting glutathione-dependent enzymes, while 'Namdokmai' limited Aβ peptide formation via BACE-1 inhibition and amended locomotory behavior of the AD model. Results indicated the potential anti-AD properties of tropical fruits, particularly 'Namdokmai' in the prevention of Aβ -mediated neurotoxicity and as a BACE-1 blocker.