Although the in vitro neuroprotective action of curcumin (and astragaloside) in depression has been suggested to be mediated by the tyrosine protein kinase (TRK) β/MAPK/PI3K/CREB signaling pathways-induced upregulation of BDNF (brain-derived neurotrophic factor) [177], in in vivo models, the antidepressant properties of curcumin have been found to be involved via AKT1, NRF2, and ARE signaling [65,71]. Here, BDNF is linked to major depressive disorder.