Major depressive disorder (MDD) is one life-threatening disorder that is prevalent worldwide. The evident etiology of this disease is still poorly understood. Currently, herbal medicine is gaining more interest as an alternative antidepressant. Oroxylum indicum, which is used in traditional medicine and contains a potential antidepressive compound, baicalein, could have an antidepressive property. An in vitro monoamine oxidase-A (MAO-A) inhibitory assay was used to preliminarily screening for the antidepressant effect of O. indicum seed (OIS) extract. Mice were subjected to unpredictable chronic mild stress (UCMS) for 6 weeks, and the daily administration of OIS extract started from week 4. The mechanisms involved in the antidepressive activity were investigated. The OIS extract significantly alleviated anhedonia and despair behaviors in the UCMS-induced mouse model via two possible pathways: (i) it normalized the HPA axis function via the restoration of negative feedback (decreased FKBP5 and increased GR expressions) and the reduction in the glucocorticoid-related negative gene (SGK-1), and (ii) it improved neurogenesis via the escalation of BDNF and CREB expressions in the hippocampus and the frontal cortex. In addition, an HPLC analysis of the OIS extract showed the presence of baicalin, baicalein, and chrysin as major constituents. All of the results obtained from this study emphasize the potential of OIS extract containing baicalin and baicalein as an effective and novel alternative treatment for MDD.

Major depressive disorder (MDD) is one of life-threatening disorders that is prevalent worldwide. The evident etiology of this disease is still poorly understood. Therefore, a possible mechanism is used to evaluate the antidepressant effect. Nowadays, herbal medicine is gaining more interest as an alternative antidepressant. Oroxylum indicum, which is used in traditional medicine and contains a potential antidepressive compound, baicalein, has an antidepressive property. In vitro inhibitory effect on monoamine oxidase-A (MAO-A) enzyme was used to preliminarily screen the antidepressant effect of the O. indicum seed (OIS) extract. Mice were subjected to unpredictable chronic mild stress (UCMS) for 6 weeks and daily administration of the OIS extract started from week 4. The mechanisms involved in antidepressive activity were investigated. The OIS extract significantly alleviated anhedonia and despair behaviors in UCMS-induced mouse model via two possible pathways: (i) normalize the HPA-axis function by restoration of negative feedback (decreased FKBP5 and increased GR expressions) and reduction of glucocorticoid-related negative gene (SGK-1), (ii) improve neurogenesis by escalation of BDNF and CREB expression in the hippocampus and the frontal cortex. HPLC analysis of the extract showed the presence of All the results obtained from this study emphasize its potential as an effective and novel alternative treatment for MDD.