TABLE 1.

Use of aromatic plants’ volatiles or essential oils to treat neuropsychiatric disorders.

Scientific name	Main active ingredients	Main indications	Mechanism of action	References
Lavender (Lavandula angustifolia Mill.) Essential Oil	Linalyl acetate, linalool, (E)-β- stilbene, limonene	Anxiety Depression Sleep disorder	↑: Parasympathetic nervous system	López et al. (2017); Ozkaraman et al. (2018) ; Mahdavikian et al. (2020); Kim M. et al. (2021)
			↑: Dopamine receptors subtype D3
			↑: Alpha waves in the brain
			↓: NMDA receptors
			↓: Serotonin transporter (SERT)
Roman Chamomile (Chamaemelum nobile L.) Essential Oil	Angelic acid, tiglic acid, α-pinene, and 2-methyl butanoic acid	Anxiety Depression Sleep disorder	↑: Mitochondrial function	Kong et al. (2017); Ebrahimi et al. (2021); Jia et al. (2021)
			↑: Expression of parvalbumin mRNA in hippocampus
			↑: Neuroactive ligand- receptor interactions
			↑: 5-hydroxytryptamine
			synapses
Bergamot (Citrus bergamia Risso et Poiteau) Essential Oil	Monoterpenes limonene, monoterpene esters, linalyl acetate, and linalool	Anxiety Depression Sleep disorder	↑: Synaptic transmission	Costa et al. (2010); Donato et al. (2014); Watanabe et al. (2015); Rombolà et al. (2017)
			↑: EEG activity
			↑: Neuroprotective effects
Lemon Balm (Melissa officinalis L.) Essential Oil	Citral, citronellal, linalool, geraniol and β-caryophyllene-oxide	Anxiety Depression Fatigue	↑: Dopamine	Komiya et al. (2006)
			↑: Serotonin
Saint John’s wort (Hypericum perforatum L.) extracts	Germacrene D, (E)-caryophyllene, 2-methyl octane, α-pinene, hypericin, proto-hypericin	Anxiety Depression Sleep disorder	↑: Serotonergic system	Wong et al. (2004); Linde et al. (2008); Di Pierro et al. (2018)
			↓: Monoamine neurotransmitters
Rhodiola rosea L. (R. rosea L.) extracts	Cinnamyl alcohol glycosides such as rosin, rosavin, and the phenylethanoid compound salidroside with its aglycone tyrosol	Anxiety Depression Sleep disorder Fatigue	↑: Neurotransmitters	Panossian et al. (2010); Alperth et al. (2019); Panossian et al. (2021); Kim K. J. et al. (2021)
			↑: BDNF/TrkB signaling pathway
			↓: Anti-inflammatory action
			↓: Glucocorticoid receptor
			↓: Activity of HPA axis
Cang-ai volatile oil	Eugenol, 1,8-cineole, patchouli alcohol, acetyl eugenol, linalool, linalyl acetate	Depression	↑: Dopamine	Chen et al. (2019)
			↑: 5-hydroxytryptamine

↑, enhance, activate or increase; ↓, weaken, inactivate or decrease.