Schisandra chinensis for dementia: a narrative overview of reviews

Introduction. Schisandra chinensis is a plant of Chinese origin with characteristic red berries ("five flavor fruit") used for various medicinal purposes. The aim of this review is to understand if S. chinensis and its active compounds can have beneficial effects for age- and disease-related cognitive decline.

Methods. PubMed, Cochrane Library, and Google Scholar were searched for relevant reviews with the following keywords: "Schisandra chinensis", "schisandrin", "dementia", "cognitive", "ageing", "brain", "Alzheimer*". All databases were screened up to October 12th, 2020. Priority was given to literature reviews and network pharmacological studies.

Results. After article screening and selection, two PubMed-indexed reviews and a network pharmacological study were included. Bioactive compounds of S. chinensis are mostly lignans such as schisandrin A, schisandrin B, schisandrin C, gomisin A, schisanthenol, and schisantherin A. The majority of available studies were conducted in mice and rat models reproducing neuro-degeneration and brain damage. Based on laboratory findings, S. chinensis seemed capable of reducing amyloid-β-induced and glutamate-induced neurotoxicity, decreasing neuro-inflammation (IL-1, IL-6, TNF-alpha, inducible NOS, PGE-2, COX-2), regulating neuronal apoptosis (calcium signaling pathway),and improving mood, cognitive performance and memory. Limited clinical evidence suggested that S. chinensis may improve cognitive performance when administered in combination with Eleutherococcus senticosus and Rhodiola rosea.

Discussion. S. chinensis might have neuro-protective effects against some brain degenerative pathomechanisms and can be a valid option to study with dedicated clinical investigations.