Alzheimer's disease (AD) is a major neurodegenerative disease, associated with the hallmark proteinacious constituent called amyloid beta (Aβ) of senile plaques. Moreover, it is already established that metals (particularly copper, zinc and iron) have a key role in the pathogenesis of AD. In order to reduce the Aβ plaque burden and overcome the side effects from the synthetic inhibitors, the current study was designed to focus on direct inhibition of with or without metal-induced Aβ fibril formation and aggregation by using olive biophenols. Exposure of neuroblastoma (SH-SY5Y) cells with Aβ42 resulted in decrease of cell viability and morphological changes might be due to severe increase in the reactive oxygen species (ROS). The pre-treated SH-SY5Y cells with olive biophenols were able to attenuate cell death caused by Aβ42, copper- Aβ42, and [laevodihydroxyphenylalanine (l-DOPA)] l-DOPA-Aβ42-induced toxicity after 24 h of treatment. Oleuropein, verbascoside and rutin were the major anti-amyloidogenic compounds. Transgenic mice (APPswe/PS1dE9) received 50 mg/kg of oleuropein containing olive leaf extracts (OLE) or control diet from 7 to 23 weeks of age. Treatment mice (OLE) were showed significantly reduced amyloid plaque deposition (p < 0.001) in cortex and hippocampus as compared to control mice. Our findings provide a basis for considering natural and low cost biophenols from olive as a promising candidate drug against AD. Further studies warrant to validate and determine the anti-amyloid mechanism, bioavailability as well as permeability of olive biophenols against blood brain barrier in AD.
Keywords: Alzheimer’s disease; SH-SY5Y cells; amyloid beta; oleuropein; olive biophenols; rutin; verbascoside.