Phytochemicals as Micronutrients: What Is their Therapeutic Promise in the Management of Alzheimer’s Disease?

Abstract

Alzheimer’s disease (AD) is a debilitating neurodegenerative disease with devastating outcomes to patients and exhaustive burdens to healthcare systems. Alzheimer’s disease has always been the focus of extensive research since its discovery in the early 1900s; however, AD continues to wreak havoc among the elderly population. Unfortunately, until now AD is still without any defined treatment that can curb its otherwise insidious progression. In the wake of this crisis and in the absence of a restorative cure, alternative approaches to AD management have been sought. In this regard, phytochemicals—a class of micronutrients composed of herbal or plant secondary metabolites— have shown potential as novel agents in the management of several diseases including cancer, hyperlipidemia, cardiovascular diseases, hyperglycemia, and neurodegenerative disorders including AD. Phytochemicals therapeutic abilities can be attributed to their ability to protect against several AD pathologic events such as inflammation, oxidative stress, protein misfolding, aggregation, and several more. In this chapter, we overview AD and its progression to pathology. Next, we highlight the available conventional treatments currently used to mitigate symptoms of AD. Then, we expose phytochemicals and their known therapeutic potential in several diseases including neurodegenerative disorders. Lastly, we explore the available literature concerning the use of phytochemicals in the management of AD. Specifically, light is shed on the possible curative capacity of certain plant phytochemicals—namely those of Ginkgo biloba, Piper nigrum, Withania somnifera, Lavandula angustifolia, Olea europaea, Nigella sativa, Ficus carica, and Panax ginseng—in the management of AD. Mechanisms by which extracts of these plants exert their neuroprotective effects are discussed alongside other aspects pertaining to the efficacy, safety, and druggability of some of these phytochemicals. We conclude that phytochemicals have shown promise in the management of AD. However, clinical trials remain lacking in this area and extensive efforts need to be exerted to determine the safety, efficacy, and exact modes of action of phytochemicals in human AD patients.