Herbs for Alzheimer disease – A Review

Many medicinal plants have been used traditionally for the treatment of Alzheimer's disease (AD). Medicinal Plants are the valuable source of phytochemical agents and give templates to develop synthetic or semi-synthetic drugs. The uses of medicinal plants or herbal medicines are still popular in the field of drug development to treat AD. But more research is needed to produce scientific support for efficacy and safety of medicinal plants in the treatment of AD. Few drugs available (galantamine and rivastigmine) to treat AD and these drugs are derived from medicinal plants; galantamine is obtained from the bulbs and flowers of Galanthus caucasicus and rivastigmine having chemical structure of physostigmine from Physostigma venenosum. This review discusses about the ethno-botanical uses of medicinal plants to treat Alzheimer's disease. © 2013 Universal Research Publications. All rights reserved Introduction Alzheimer's disease (AD) has become one of the common diseases in aged population. It is a neuro-degenerative disease and the most common cause of dementia. Dementia is a brain disorder and affects a person's ability to carry out daily activities (long-term memory loss, confusion, aggression, irritability and mood swings). AD is predicted to affect more than 22 million people worldwide in future. The neuropathology history of AD is not completely explained yet. Therefore, cholinergic hypothesis theory has been accepted and resulting from the cholinergic shortage emerging in the brains of AD patients [1]. Shortage of the neurotransmitters such as acetylcholine and butyrylcholine has been recognized, and therefore, inhibition of the enzymes; acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) that break down acetylcholine and butyrylcholine has considered a standard approach for treatment of AD [2]. Another hypothesis in the pathogenesis of AD is that formation of amyloid plaques containing beta-amyloid peptide in the brains of AD patients. Beta-amyloid peptide is produced after the sequential cleavage of amyloid precursor protein, especially beta and gamma-secretase in the amyloidogenic pathway. This secretases involved in the processing of amyloid precursor protein. The inhibition of secretase enzyme has become another approachin treatment of AD [3, 4]. In addition, medicinal plants also used to treat the AD in Indian traditional system. The medicinal plants have the attractive sources of phytochemical agents with favored biological activities [5]. The aim of this article is to review the ethno-botanical uses of medicinal plants to treat Alzheimer's disease. Phytochemical agents or medicinal plants for Alzheimer's disease Sesquiterpene lactones (Amberin, Amberbin-A, AmberbinB and Amberbin-C) have been isolated from ethyl acetate soluble fraction of Amberboa ramosa. These compounds were tested for their inhibitory potential against acetyl cholinesterase and butyryl cholinesterase enzymes using Ellman's colorimetric assay. All compounds showed potential inhibitory activities against acetyl cholinesterase and butyryl cholinesterase. This study indicated that sesquiterpene lactone could be effective against Alzheimer's disease [6]. The methanol extracts of Adhatoda vasica and Ferula assafoetida were subjected to in vitro assay against acetylcholinesterase (AChE) and cycloxygenase-1 (COX-1) enzymes. The results indicated that Adhatoda vasica exhibited inhibitory effect on AChE and Ferula assafoetida showed inhibitory activity against COX-1 enzyme. This study suggested that Adhatoda vasica and Ferula assafoetida might be promising agents for treatment of AD [7]. The effect of safranal (a constituent of Crocus sativus) pretreatment was investigated on quinolinic acid (QA)-induced oxidative damage in rat hippocampus. Systemic administration of safranal (291 mg/kg, IP), dosedependently decreased the QA-induced lipid peroxidation and oxidative DNA damage. This study indicated that Available online at http://www.urpjournals. com International Journal of Research in Plant Science Universal Research Publications. All rights reserved