Psychoactive plants and phytochemicals

Central nervous system disorders such as anxiety, depression, and Alzheimer’s occur as a result of the imbalance of neurotransmitters such as acetylcholine (Ach), dopamine (DA), serotonin (5-HT), and/or γ-aminobutyric acid (GABA). Such disorders may lead to emotional changes as well as impaired cognitive functions. Plants have been the predominant source of medicines throughout the vast majority of human history and remain so today outside of industrialized societies. Many plants are known for their anxiolytic, antidepressant, and memory-enhancing properties. Moreover, phytoconstituents, particularly alkaloids, have proven effectiveness as psychoactive lead drugs. In this chapter, we will have an overview of the most important psychoactive, neuroprotective, and antidepressant plants and phytoconstituents with emphasis on their mechanism of action.