ABSTRACT
The existing antidepressants demonstrated delayed onset of clinical effects, so fast-onset antidepressants are required. Essential oil of herbs showed potentials fast-onset antidepressant potential. First, its aromatic odor can directly activate olfactory nerves; its high lipophilicity causes a high blood-brain barrier penetration rate; and its high volatility is suitable for nasal-brain targeting and inhalation delivery. Therefore, essential oils can rapidly regulate brain functions by multiple ways, suggesting a fast-onset antidepressant potential. Second, the advance of studies on chemistry and pharmacology of antidepressant essential oils demonstrated chemical substances, antidepressant effects and possible action mechanisms of antidepressant essential oils. Third, the effect of essential oils' antidepressant components on fast-onset antidepressant targets was investigated. It was found that chemical constituents of essential oils antagonized NMDA receptor activities, suggesting that essential oils have fast-onset antidepressant effect. Finally, characteristics of essential oils, fast-onset antidepressant targets and drug delivery methods are integrated to give full play to essential oils' fast-onset antidepressant advantage and provide a new direction for new drug discovery.