Characterization of the Anticholinesterase and Antioxidant Properties of Phytochemicals from Moringa oleifera as a Potential Treatment for Alzheimer's Disease.

Background/

Objectives

Alzheimer's disease (AD) is the most prevalent form of dementia and is characterized by a decline in cognition that may be due, in part, to deficient cholinergic signalling. Cholinesterase inhibitors (ChEIs) are the first-line pharmacotherapies for treating the diminished cholinergic function in AD patients. Plant phytochemicals may provide useful ChEIs and mitigate other elements of AD pathology, including oxidative stress.

Methods

Herein, the phytochemicals present in Moringa oleifera aqueous and methanolic extracts were identified by LC-MS/MS and the potential of several phytochemicals (4-O-caffeoylquinic acid (4-CQA), quercetin 3-β-D-glucoside (Q3-β-D), chlorogenic acid (CGA), and rutin) to act as ChEIs and antioxidants was assessed.

Results

The phytochemicals inhibited human acetylcholinesterase (AChE) in the following order of potency: 4-CQA > Q3-β-D > CGA > rutin; for AChE from Electrophorus electricus, the order of potency was Q3-β-D > 4-CQA > CGA > rutin. For human butyrylcholinesterase (hBuChE), the order of potency was rutin > 4-CQA > Q3-β-D > CGA and for equine serum BuChE, it was 4-CQA > Q3-β-D > rutin > CGA. Molecular docking validated the binding of the phytochemicals to cholinesterases, with binding affinities comparable to or higher than those of ChEI drugs. All the phytochemicals displayed potent radical-scavenging and antioxidant activities across six assays. 4-CQA was the most effective antioxidant in three of the assays.

Conclusions

M. oleifera contains phytochemicals with weak ChEI activity and potent antioxidant capacity, with potential use as nutraceuticals to treat the cholinergic signalling deficit and oxidative stress that typifies AD pathology.