Abstract

Alzheimer’s disease (AD), a common neurodegenerative disease, is characterized by low levels in the brain of the neurotransmitter, acetylcholine (ACh). Clinical treatment of this disease is palliative and relies mostly on enhancing cholinergic function by stimulation of cholinergic receptors or prolonging the availability of ACh released into the neuronal synaptic cleft by use of agents which restore or improve the levels of acetylcholine. Inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), enzymes which breakdown acetylcholine, are considered as a promising strategy for the treatment of AD. A potential source of AChE and BChE inhibitors is provided by the abundance of plants in nature, and natural products continue to provide useful drugs and templates for the development of other compounds. The present work constitutes a review of the literature on 123 species of medicinal plants that have been tested for AChE inhibitory activity and 42 plant species which have been tested for BChE inhibitory activity. The plant species listed are potential cholinesterase inhibitors and may aid researchers in their study of natural products which may be useful in the treatment of AD.

Key words: Alzheimer’s disease, acetylcholine, acetylcholinesterase, butyrylcholinesterase and medicinal plants.

Abbreviation

Abbreviations: AD, Alzheimer’s disease; CNS, central nervous system; ACh,acetylcholine; AChE, acetylcholinesterase; BChE, butyrylcholinesterase; DTNB, 5,5´-bisdithionitrobenzoic acid; ATCI, acetylthiocholine iodide;  BTCCl, butyrylthiocholine chloride; TLC, thin layer chromatography; DPPH, diphenyl picryl hydrazine; XO,xanthine oxidase; EtOAc, ethylacetate; BHA, butylated hydroxyanisole; OSI, oxidative stability instrument; BHT, butylated hydroxytoluene.