Table 3.

Pleiotropic activities of selected natural products studied in humans. Studies and mechanism of enhancing positive mood and activating the brain reward system are also summarized.

Natural Product	Preclinical Data on Antidepressant Activities and Interactions with the Reward System	Refs.
Curcumin	Decreased serum corticosterone levels Increases serotonin by inhibition of monoamine oxidases	[14, 102-105]
	Reduce immobility time and stressed-induced neurodegeneration	[88, 91]
n-3 PUFA	Stabilizes/increases levels of brain serotonin, affects serotonergic transmission	[12]
Resveratrol	Increased serotonin levels in the brain Inhibition of monoamine oxidases (MAO-A)	[106]
L-acetylcarnitine	Enhances dopamine release Upregulation of mGlu2 Receptors	[107-109]
L-Theanine	Increases dopamine levels in the brain Increased levels of BDNF	[110] [31]