With the increase in the expectancy of the life span of humans,
neurodegenerative diseases (
NDs) have imposed a considerable burden on the family, society, and nation. In defiance of the breakthroughs in the knowledge of the pathogenesis and underlying mechanisms of various
NDs, very little success has been achieved in developing effective
therapies. This review draws a bead on the availability of the nutraceuticals to date for various
NDs (
Alzheimer's disease,
Parkinson's disease,
Amyotrophic lateral sclerosis,
Huntington's disease, vascular
cognitive impairment,
Prion disease,
Spinocerebellar ataxia,
Spinal muscular atrophy,
Frontotemporal dementia, and
Pick's disease) focusing on their various mechanisms of action in various in vivo and in vitro models of
NDs. This review is distinctive in its compilation to critically review preclinical and clinical studies of the maximum
phytochemicals in amelioration and prevention of almost all kinds of
neurodegenerative diseases and address their possible mechanism of action. PubMed, Embase, and Cochrane Library searches were used for preclinical studies, while ClinicalTrials.gov and PubMed were searched for clinical updates. The results from preclinical studies demonstrate the efficacious effects of the
phytochemicals in various
NDs while clinical reports showing mixed results with promise for
phytochemical use as an adjunct to the conventional treatment in various
NDs. These studies together suggest that
phytochemicals can significantly act upon different mechanisms of disease such as oxidative stress,
inflammation, apoptotic pathways, and gene regulation. However, further clinical studies are needed that should include the appropriate
biomarkers of
NDs and the effect of
phytochemicals on them as well as targeting the appropriate population.