NOS2 and major depressive disorder: Flavoprotein (FX) is an edible brown seaweed rich in natural carotenoids, and FX can prevent LPS-induced depression-like behavior in mice by modulating the AMPK-NF-κB signaling pathway and downregulating pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) as well as overexpression of iNOS and COX-2 in the hippocampus, frontal cortex, and hypothalamus (130).