ABSTRACT
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by a low level of neurotransmitter acetylcholine (ACh) in the brain. AD is an irreversible age-related form of dementia that slowly erodes the brain and robs the person of memory and cognitive skills, causing changes in personality and behavior. During the last decade, significant growth in Alzheimer’s prevalence has ignited the importance of more researches to search for new medicine. One of the major clinical advances in the treatment of AD has been the use of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors to alleviate ACh levels in the brain, although cholinergic compounds with nicotinic and muscarinic agonist properties also have attracted some interest. At present, there are very limited medications available to treat AD, and most of the treatment is available only to delay the progression of symptoms and symptomatic relief for a short period of time. Medicinal plants represent a large untapped reservoir of natural medicines and potential sources of natural AChE inhibitors. The structural diversity of their phytoconstituents makes them a valuable source of novel lead compounds for the quest of drugs to treat AD. Therefore, systematic ethnopharmacological screening of these plants may provide useful leads in the discovery of new drugs for AD therapy. With this background, a systematic review is prepared to bring forth an updated knowledge in various phytoextracts and their derivatives along with their possible action on the cholinergic nervous system to ease AD therapy. Electronic databases were used for searching the information related to studies performed in plants during the last decades.
