As an inhibitor of 5-LO (Jin et al., 2011), emodin prevented the depression behaviors along with a series of pathological changes in the hippocampus, such as hippocampal neuron and spine loss, microglial activation, increased IL-1β and TNF-α, and the activation of 5-LO and GSK3β. This evidence concerns the gene GSK3B and major depressive disorder.