NOS2 and major depressive disorder: also confirmed the anti‐depressive effects of HCE with a lipopolysaccharide (LPS)‐induced mice model of depression, resulting that HCE significantly reversed the decrease of sucrose preference in mice due to the activating expression of iNOS (inducible nitric oxide synthase), NF‐κB (nuclear factorkappa B), and COX‐2 (cyclooxygenase‐2) in the prefrontal cortex by LPS (Li et al., 2017).