Nose-to-Brain Delivery System for Incorporating Monoterpenes with Anti-Depressant Potential

Depression is a prevalent and disabling disease influenced by genetic, immunological, and environmental factors. Although conventional treatments are effective, they face limitations such as treatment resistance and side effects. Monoterpenes, components of essential oils, exhibit diverse pharmacological activities, including antidepressant effects, attracting growing research interest. This narrative review analyzed literature on monoterpenes with potential antidepressant properties, focusing on their biological effects and mechanisms of action. The study reviewed data from Google Scholar, Science Direct, and PUBMED using terms such as "Depression," "Essential oils," "Phytochemical compounds," and "Central nervous system." The review identified 29 monoterpenes with antidepressant-like effects, acting through dopaminergic, serotonergic, noradrenergic, glutamatergic, GABAergic, and endocannabinoid systems. They also modulate neuroinflammation, HPA axis hyperactivity, and neuroplasticity pathways. These findings position monoterpenes as promising candidates for developing safer and more effective antidepressant drugs. Additionally, monoterpenes possess characteristics that facilitate their use in nose-to-brain delivery systems, enabling direct and efficient central nervous system access. This innovative route could enhance therapeutic effects while minimizing side effects associated with traditional treatments. Overall, monoterpenes represent a promising avenue for advancing antidepressant therapy, particularly through novel intranasal formulations that leverage their pharmacological properties for improved safety and efficacy.