Table 3.

Effects of different dietary polyphenols on mental-health-related states and behaviour, particularly anxiety and depression. EGC: epigallocatechin; GT: green tea.

Reference	Polyphenol	Treatment	Model	Effect on mental health/behavior	Proposed molecular mechanism(s)
An et al. 2008 [39]	Flavanoids	XBXT-2 (25 or 50 mg/kg), imipramine (10 mg/kg, p.o.)	Sprague Dawley rats submitted to chronic stress	Antidepressant-like effect	Increased neurogenesis and expression of hippocampal BDNF and pCREBas one of the molecular and cellular mechanisms underlying the antidepressant action of XBXT-2
Duffy et al. 2008 [42]	Blueberry	2% blueberry extract versus control diet over 8 weeks	Fischer-344 rats submitted to kainate-induced learning impairment	Blueberry diet reduced memory impairment Less loss of CA1 pyramidal neurons	Possible involvement of MAPK
van Praag et al. 2007 [43]	Flavanoids (‒) epicatechin	(‒) epicatechin diet ad libitum versus control ad libitum	C57/Bl6 mice (runner versus non-runner)	(‒) epicatechin improved memory in Morris water maze especially in combination with exercise	Increase of angiogenesis and spine density
Messaoudi et al. 2008 [48]	Cocoa	Effective doses of cocoa: 24 mg/kg/14 days and 48 mg/kg/14 days	Wistar rats	Antidepressant- like effects measured in the Forced swimming test	Reversal of oxidative damage
Sathyapalan et al. 2010 [49]	Cocoa	High cocoa liquor/polyphenol rich chocolate diet or cocoa liquor free/low polyphenol diet for 8 weeks	Human fatigue syndrome patients	Chalder Fatigue Scale score improved significantly after 8 weeks of the HCL/PR diet
Xu et al. 2005 [50]	Curcumin	Curcumin (1.25, 2.5, 5, 10 mg/kg), or moclobemide (20 mg/kg), imipramine (10 mg/kg)	ICR mice	Curcumin also significantly inhibited immobility in FST	Antidepressant-like effects of curcumin may involve the central monoaminergic neurotransmitter systems
Xu et al. 2010 [51]	Trans-Reservatrol	t rans-Resveratrol (20, 40 and 80 mg/kg, via gavage)moclobemide (20 mg/kg, i.g.), imipramine (10 mg/kg, i.p.), and fluoxetine (10 mg/kg, i.p.)	ICR mice	Decreased the immobility time in mouse models of despair	Antidepressant-like effect of trans-resveratrol might be related to serotonergic and noradrenergic activation
Zhu et al. 2011[52]	Green tea/epigallocatechin	Orally administered green tea polyphenols (GTP; 5, 10 and 20 mg/kg) for 7 days Forced swimming test (FST) and tail suspension test (TST) 60 min after the last GTP administration	ICR mice	Antidepressive- like effects	May involve inhibition of HPA axis; possibility that chronic GTP treatment can reduce HPA axis hyperactivity in response to stress
Xu et al. 2009 [53]	Curcumin	Curcumin (5, 10, and 20 mg/kg, p.o.) or imipramine (10 mg/kg, i.p.)	Sprague-Dawley rats submitted to chronic stress	Curcumin reversed impaired spatial memory under conditions of chronic stress	Normalizing corticosterone levels and downregulating pCaMKII and glutamate receptor levels
Assunção et al. 2011 [58]	Green tea/epigallocatechin	19-month-old rats were fed with GT since age of 12 months	Wistar rats	Spatial learning abilities of GT-treated rats were significantly improved	Scavenging of free radicals
Xu et al. 2010 [61]	Green tea/epigallocatechin	GT polyphenols were administered orally to rats from 4 to 8 weeks after experimentally induced cerebral hypoperfusion (400 mg/kg per day or 100 mg/kg)	Wistar rats	Inhibited cognitive impairment Improved spatial learning and memory deficits induced by chronic cerebral hypoperfusion	Free radical scavenging and antioxidative properties of GT polyphenols
Bouayed et al. 200 [67]	Chlorogenic acid (Mirabelle)	20 mg/kg	Mouse model of anxiety	Decreased in anxiety-related behaviours	Anxiety is reduced by activation of the benzodiazepine receptor
Vignes et al. 2006 [68]	Green tea/epigallocatechin	Acute administration—drugs injected intraperitoneally in a volume of 100 μL per 20 g of body weight	Swiss OF1 mice	Anxiolytic effect in the elevated plus maze and passive avoidance tests	Anxiolytic effect could result from an interaction of the given polyphenols with GABAA receptors
Barros et al. 2006 [69]	Vaccinium berries	Water with berry extract over 30 days (0.6–1.0 mg/kg/day or 2.6–3.2 mg/kg/day)	Swiss mice	Decreased DNA damage in hippocampal tissue Anxiolytic effect in open-field test	Protective effect against free radical-induced DNA damage in the brain
Hou et al. 2010 [70]	Flavanols (Gingko biloba extract)	In vivo: 50 mg/kg per day for 4 months	In vivo: APPswe/P1D9 transgenic mice and wildtype	In vivo: increased levels of BDNF in hippocampus; anti-depressant effects in wt mice	Increase in BDNF and glutamate-evoked activation of pCREB
		In vitro: 24 h incubation	In vitro: primary neuronal cells	In vitro: flavonols dose-dependently restored BDNF expression compared to vehicle control; increase of pCREB through glutamate-evoked activation
Chen et al. 2010 [71]	Green tea/epigallocatechin	GTEs and EGCG 0.1 g/d	Wistar rats	Improved the cognitive impairments induced by stress	Involved with changes in plasma levels of catecholamines, 5-hydroxytryptamine, cytokines and expression of metallothioneins
Singal et al. 2004 [72]	Green tea/epigallocatechin	1. 50 μg i.p. of endotoxin LPS in 250 μL of pyrogen-freesaline 2. Green Tea Extract (GTE - 10, 25, 50, and 100 mg/kg)	Albino laca mice	Reversal of LPS-induced immobility	COX-2 inhibition by GTE
Sanmukhani et al. 2011 [73]	Curcumin	Acute study: treatment 24, 5, and1 h before test: curcumin 50 mg/kg, 100 mg/kg, vehicle, fluoxetine, and imipramine control	Acute study: Swiss albino mice	Antidepressant-like effects in FST and TST at 100 mg/kg in acute and chronic study	Increases neural levels of serotonin, noradrenaline and dopamine possibly via inhibition of MOA activity
		Chronic study: treatment for 14 days, same doses as in acute	Chronic study: Wistar rats
Xu et al. 2006 [74]	Curcumin	Curcumin (2.5, 5, and 10 mg/kg, p.o.) or imipramine (10 mg/kg, i.p.)	Sprague–Dawley rats submitted to chronic stress	Curcumin reversed the effects of chronic stress on behaviour	Effects of curcumin on the behavioural deficits induced by chronic stress may be related to modulating effects on the HPA axis; increased in BDNF and pCREB proteins in specific brain regions may also be related
Wu et al. 2006 [75]	Curcumin	Diet with and w/o curcumin (500 ppm) for 4 weeks	Sprague-Dawley rats submitted to fluid percussion injury	Curcumin-fed injured animals had lower levels of oxidized proteins and counteracted cognitive impairment	Modulation of BDNF-system which acts on CREB and synapsin