The Red Berry and the Brain: Lycium barbarum Polysaccharides in Neuroprotection

Psychiatric and neurodegenerative disorders continue to contribute significantly to disability and mortality worldwide, a situation exacerbated by the lack of effective treatments capable of altering the course of these diseases, which poses a huge challenge to public health on a global scale. Lycium barbarum polysaccharides (LBPs), the major active components of Lycium barbarum, have attracted increasing attention owing to their promising neuroprotective properties demonstrated in cellular and animal disease models. This review summarises existing research on the mechanisms by which LBPs exert therapeutic effects in various cellular and animal models of neurological conditions. More specifically, it highlights the role of LBPs in attenuating Parkinson’s disease by modulating the nuclear factor erythroid 2/haem oxygenase-1 (Nrf2/HO-1) pathways and the reactive oxygen species and nitric oxide (ROS-NO) pathways, in alleviating Alzheimer’s disease by reducing beta-amyloid (Aβ) accumulation, as well as in attenuating ischaemia–reperfusion injury by modulating the Wnt/β-catenin pathway and mitochondrial dynamics. Furthermore, this review explores the potential of LBPs in the treatment of depression, whilst emphasising the urgent need to expand mechanistic studies beyond the prevailing inflammatory hypothesis. Through an integrative analysis of these molecular targets and signalling networks, this review establishes a comprehensive theoretical framework, proposes future research directions, and provides a theoretical basis for the use of LBPs in the treatment of neuropsychiatric disorders.