Furthermore, Xiaoyao pills has antioxidant and neuroprotective effects on both cortical and hippocampal regions, which can improve depression-like behavior and oxidative stress of olfactory bulb excised rats by activating PIK3CA-AKT1-NFE2L2 BDNF signaling pathway (Ji et al., 2021). This evidence concerns the gene BDNF and major depressive disorder.