Withania somnifera (L.) Dunal, a Potential Source of Phytochemicals for Treating Neurodegenerative Diseases: A Systematic Review

Abstract

Withania somnifera (L.) Dunal is a medicinal plant belonging to the traditional Indian medical system, showing various therapeutic effects such as anti-cancer, anti-inflammatory, anti-microbial, anti-diabetic, and hepatoprotective activity. Of great interest is W. somnifera’s potential beneficial effect against neurodegenerative diseases, since the authorized medicinal treatments can only delay disease progression and provide symptomatic relief and are not without side effects. A systematic search of PubMed and Scopus databases was performed to identify preclinical and clinical studies focusing on the applications of W. somnifera in preventing neurodegenerative diseases. Only English articles and those containing the keywords (Withania somnifera AND “neurodegenerative diseases”, “neuroprotective effects”, “Huntington”, “Parkinson”, “Alzheimer”, “Amyotrophic Lateral Sclerosis”, “neurological disorders”) in the title or abstract were considered. Reviews, editorials, letters, meta-analyses, conference papers, short surveys, and book chapters were not considered. Selected articles were grouped by pathologies and summarized, considering the mechanism of action. The quality assessment and the risk of bias were performed using the Cochrane Handbook for Systematic Reviews of Interventions checklist. This review uses a systematic approach to summarize the results from 60 investigations to highlight the potential role of W. somnifera and its specialized metabolites in treating or preventing neurodegenerative diseases.

Acute and Repeated Ashwagandha Supplementation Improves Markers of Cognitive Function and Mood

“…Ashwagandha has been reported to possess antioxidant [ 9 , 14 , 15 , 16 ], anti-inflammatory [ 9 , 11 , 12 ], neuroprotective [ 8 , 10 , 15 , 23 , 24 , 25 , 26 ], endocrinological [ 17 , 18 , 19 , 20 , 21 ], and immune-modulatory properties [ 10 , 22 ] that influence cognition [ 1 , 23 , 25 , 31 ]. Preliminary human clinical trials indicate that ashwagandha supplementation may have therapeutic benefits in individuals with medically managed bipolar disease [ 32 ], mild cognitive impairment [ 33 ], and chronic stress [ 7 ].…”

“…Ashwagandha has antioxidant properties [ 9 , 14 , 15 , 16 ], influences endocrine function [ 17 , 18 , 19 , 20 , 21 ], and has immunomodulatory effects [ 10 , 22 ]. Ashwagandha supplementation has been reported to attenuate cognitive decline associated with inflammation [ 9 , 11 , 12 ] and neurodegeneration [ 8 , 10 , 15 , 23 , 24 , 25 , 26 ]. Since oral ingestion of ashwagandha is bioavailable and crosses the blood–brain barrier [ 24 ], ashwagandha has been considered a naturally occurring therapeutic agent for individuals with type 2 diabetes mellitus [ 9 , 10 , 25 ], mild cognitive impairment [ 8 , 11 , 14 ] and individuals with neurodegenerative diseases [ 14 , 15 , 24 , 27 , 28 , 29 ].…”