TNF and major depressive disorder: The natural carotenoid crocin, contained in saffron and gardenia flowers (crocuses and gardenias), exhibits a variety of pharmacological effects, including an anti-inflammatory action due to the reduction of lipopolysaccharide (LPS), Interleukin-6, and tumor necrosis factor-α (TNF-α) levels in serum, and TNF-α expression in the hippocampus [146], as well as a neuroprotective function [147], increasing the hippocampal brain-derived neurotrophic factor, with possible potential to treat depression [148,149].