Potential of treating age-related depression and cognitive decline with nutraceutical approaches: a mini-review

A variety of consumable plant-derived phytochemicals exhibit nutraceutical properties because they produce physiological benefits and combat disease processes. Emerging evidence suggests that widely accessible and safe organic polyphenolic phytochemicals, in particular, treat depression at much lower concentrations than clinical doses of classical drugs. Structurally similar polyphenolics such as curcumin, resveratrol, and proanthocyanidins exhibit antioxidant and immunomodulatory properties and recent research suggests that they also modulate hypothalamic-pituitary-adrenal (HPA) axis activity, serotonergic transmission and hippocampal neurogenesis (perhaps via their effects on serotonin and HPA activity). These data tempt speculation that polyphenolic compounds could also combat age-related cognitive decline, which is often accompanied by depression and potentially by reduced levels of hippocampal neurogenesis. Here we review the relationships between dysregulation of these systems and age-related cognitive decline. We then suggest that this group of structurally similar polyphenolic compounds may be particularly promising therapeutic leads for age-related cognitive decline and depression because they modulate these processes.