Biol. Pharm. Bull. 29(6) 1154—1161 (2006)

become aware of our surroundings, objects and thoughts. Alzheimer’s disease (AD) represents the most common cause of dementia, affecting more than 15 million individuals worldwide. It is characterized by progressive memory loss, cognitive impairments, and personality defects accompanied by diffuse structural abnormalities in the brain. Memory forms one of the most complex functions of the brain and ultimately involves multiple neuronal pathways and neurotransmitter systems. One of the most consistent and profound change associated with AD is diminished central cholinergic neurotransmission. Therefore, facilitation of cholinergic transmission by inhibition of acetyl cholinesterase enzyme can be looked upon as an important strategy in improving cognitive and behavioral functions. The main histological hallmarks of AD are extraneuronal deposits of b-amyloid (Ab) plaques and intra neuronal fibrillary tangles. Recently, substantial evidence is accumulating in the literature showing a strong link between high cholesterol and high incidence of Alzheimer’s disease. Both the generation and clearance of Ab appear to be regulated by cholesterol. Elevated cholesterol levels increased Ab in cellular and most animal models of AD whereas, drugs that inhibited cholesterol synthesis lowered Ab . Clinical studies indicated that patients with elevated serum cholesterol levels have increased susceptibility to AD, and that the prevalence of AD is higher in countries with high-fat intake. Therefore, a new approach aimed at reducing blood cholesterol level may prove worthwhile in the management of Alzheimer’s disease. Since the Allopathic system of medicine is yet to provide a radical cure for Alzheimer’s disease, it is worthwhile to look for new directions, which would minimize the memory loss of patients with neuropsychiatric disorders. The utility of non-toxic plants may be explored for treating patients with dementia. Daucus carota LINN. commonly known as “Carrot” belongs to the family Apiaceae (Umbelliferae) and is cultivated almost all over the world as a useful vegetable. Different parts of this plant are used in Indian systems of medicine for the treatment of a broad spectrum of aliments including kidney dysfunction, asthma, dropsy, inflammation, leprosy and worm troubles. The plant has undergone extensive phytochemical studies and a large number of active ingredients have been isolated. These include volatile oils, steroids, triterpenes, carbohydrates, glycerides, tannins, flavonoids, amino acid, carotene and hydrocarotene. Pharmacological studies showed that Daucus carota seeds exhibit antifertility properties. The crude extract of root of the plant has been found to be hypoglycemic and hepatoprotective. Indian Materia Medica makes a mention of Daucus carota seeds as a brain tonic. Cholinergic activity was also found in water-soluble fraction of the alcoholic extract of seeds. Since, Daucus carota seeds have been reported to contain choline, there is a possibility to elevate the brain acetylcholine levels via increased synthesis of Ach, which would in turn prove beneficial in cognitive dysfunctions. Therefore, we were motivated to study the potential of DCE in the management of cognitive dysfunctions.