A Critical Review Based on Preclinical Studies of Medicinal Plants for the Management of Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common neurodegenerative and progressive disorder that results in damage to memory and alters thinking and behavior, which represent critical problems the world’s aging population is faced with. Clinical symptoms of AD include cognitive decline, loss of memory, emotional and behavioral changes, loss of motor coordination, and mental impairments. Yet, neither a universally accepted diagnosis with respect to its pathogenesis nor an ideal therapy is available for the management of AD. The existing drugs cause many complications and adverse effects. Herbal drugs, supported by an abundance of traditional knowledge, may fulfill the need as they can target the pathogenesis of AD at various destinations, both at the cellular and molecular levels. In recent years, herbal drugs and formulations have been evaluated in preclinical setups, especially involving rat and mouse models of AD, which have shown their memoryenhancing, neuroprotective, and antioxidant activities. Several herbal drugs and phytochemicals have been evaluated for their effectiveness as antioxidative agents to prevent the occurrence of oxidative stress and ROS formation during AD pathogenesis and exhibit antiapoptotic properties by downregulating caspase-3, DNA fragmentation, NF-κB, interleukin-1 β (IL1β), and TNF levels. In this paper, we have primarily reviewed herbal remedies that have been recently evaluated as alternative treatments for AD in a preclinical setup, and discussed the role of herbal medicines in the management of AD and advances in their knowledge.