Effects of food-derived bioactive peptides on cognitive deficits and memory decline in neurodegenerative diseases: A review

Memory and cognitive impairments/disorders are the main clinical symptoms of neurodegenerative diseases. The prevalence of such chronic conditions has increased over the past three decades. There is a growing interest in the use of food-derived bioactive products as intervention agents in functional foods and dietary supplements for the fights against these human diseases. Dietary bioactive peptides with neuroprotective and cognitive-enhancing effects are attracting increasing attention, owing to their abilities to influence cognition and mental health in vivo and in vitro. This article reviews recent studies on neuroprotective peptides to gain insights into their potential food sources, industrially feasible production methods, and duration and mechanism(s) of action. Challenges associated with the comparison of the results from published studies employing different analysis methods, complexities of raw materials and in vivo or in vitro systems, diverse sequence-derived structural and physicochemical features, and structure-activity relationships for neuroprotective peptides are all critically discussed. The current review confirms the growing interest in searching natural, effective and affordable neuroprotective peptides or protein hydrolysates, and increasing knowledge about mechanisms underlying their brain health benefits and functions against cognitive impairments. Among the in vitro and in vivo methods used to characterize and verify neuroprotective peptides, bioinformatics and peptidomics approaches emerge as cost-effective screening methods. Previous published studies mainly focused on the effects of the production methods/processes of bioactive peptides on their chemical composition and neuroprotective functions. However, the structure-activity relationships of neuroprotective peptides as well as their underlying working mechanisms and molecular pathways in the prevention and treatment of cognitive deficits have received little attention. The findings presented in this review can be used to support the design and production of neuroprotective peptides acceptable by consumers.