BDNF and major depressive disorder: By focusing on the neurotrophin (BDNF) hypothesis of depression, we herein demonstrated that the HMF treatment attenuated corticosterone-induced reductions in BDNF levels in the hippocampus (Figure 4) as well as corticosterone-induced depression-like symptoms (Figure 2 and Figure 3), suggesting that HMF has potential as an anti-depressant agent.