Alzheimer's disease (AD) is a progressive inexorable loss of cognitive function associated with the presence of senile plaques in the hippocampal area of the brain. The disease is the most common form of dementing illness among middle-aged and older adults, affecting more than 5 million Americans, a number estimated to increase to 7.7 million by 2030. Symptoms typically appear after age 60, and some early-onset forms of the disease are linked to a specific genetic defect. Although the etiology is unknown, genetic factors clearly play a role in 10% to 15% of cases [1
]. So far, e orts to find a cure for AD have been disappointing, and the drugs currently available to treat the disease address only its symptoms and with limited effectiveness. The underlying pathogenesis is a loss of neurons in the hippocampus, cortex, and subcortical structures [2
]. Early disease shows a loss of short-term memory, inability to learn new information, mood swings, difficulty in finding words, forgetting names, and losing items. Frustration, hostility, and irritability are common emotional features exhibited by patients with AD. In severe cases, patients become totally incontinent, memory is completely lost, and sense of time and place disappears. Patients become totally dependent upon others and eventually require comprehensive care. Owing to the patient's total dependency upon others, placement in a nursing home with full-time nursing care becomes necessary. Thus, AD presents a considerable problem in patient management as well. It is believed that therapeutic intervention that could postpone the onset or progression of AD would dramatically reduce the number of cases in the next 50 years [1
Herbal medicine offers several options to modify the progress and symptoms of AD. There has been a new trend in the preparation and marketing of drugs based on medicinal plants, and their scientific and commercial significance appears to be gathering momentum in health-relevant areas. These plant-derived products are carefully standardized, and their efficacy and safety for a specific application have been demonstrated [3
Ayurvedic medicine is a system of traditional medicine native to India, and Ayurvedic practitioners have developed a number of medicinal preparations and surgical procedures for the treatment of various ailments. An entire body of literature in the Ayurvedic texts deals with the nervous system and disorders associated with it. Nervous system disorders, called 'VataVyadhi' in Sanskrit, were thought to be brought on by imbalances of Vata, the biological air humor, the energy that moves through the brain and the nerves (the ancients considered nerve impulses to be a kind of wind or air traveling through the body) controlling both voluntary and involuntary functions. Hence, Vata derangements always involve some weakness, disturbance, or hypersensitivity of the nervous system. Included in these texts are direct references to age-associated memory loss, preventive care, and therapeutic interventions. These texts explain the use of several herbs and their qualities and energetics for nervous system disorders, including memory loss typically seen in older adults, but only recently have there been mechanistic studies on the role of these herbs in nervous system disorders and dementias, including dementia associated with AD [8
]. Indeed, several scientific studies have described the use of various Ayurvedic medicinal plants termed 'nervines' and their constituents to strengthen the functional activity of the nervous system and restoration of memory [8
]. Phytochemical studies have shown the presence of many valuable compounds, such as lignans, flavonoids, tannins, polyphenols, triterpenes, sterols, and alkaloids, that show a wide spectrum of pharmacological activities, including anti-inflammatory, anti-amyloidogenic, anti-cholinesterase, hypolipidemic, and antioxidant effects [5
The present review puts together research on various Ayurvedic medicinal plants that have shown promise in reversing the AD pathology. The report summarizes information concerning the phytochemical, biological, and cellular activities and clinical applications of these various plants in order to provide sufficient baseline information that could be used in drug discovery campaigns and development processes, thereby providing new functional leads for AD. Below we describe the various Ayurvedic medicinal nervine herbs that are recommended for AD and their actions on the brain.