Table 3.

Main pharmacological activities ascribed to tannins

Properties	Effects	References
Antioxidant and radical scavenging	Scavengers of hydroxyl, superoxide, and peroxyl radicals (Proanthocyanidins); Inhibition of lipid peroxidation and lipoxygenases (Ellagitannins); Stronger antioxidant activity than ascorbic acid or α‐tocopherol (Procyanidins B1 and B3); Dose‐dependent radical scavenging action of galloylated condensed tannins.	Nile and Park, 2014 Skrovankova et al., 2015 Kancheva and Kasaikina, 2013 Sieniawska, 2015
Anti‐cancer	Apoptosis p53‐dependent and Bax/Bcl‐2 proteins and caspase‐3 activation mediated in JB6 C141 cells (Grape seed proanthocyanidins); Reduction of UV‐induced oxidative stress‐mediated phosphorylation and activation of NF‐κB in NHEK cells (Grape seed proanthocyanidins); Inhibition of cellular proliferation and expression of MMP‐2 and −9 in DU145 and LNCaP cells (Grape seed proanthocyanidins); Dose‐dependent inhibition of cell viability, proliferation and apoptosis in 4 T1, HT29 and LoVo cells (Grape seed proanthocyanidins); G0/G1 phase cell cycle arrest with increase in Cip1/p21 protein levels and decrease of cyclins and cyclin‐dependent kinases in MCF‐7 and A‐427 cells (Grape seed proanthocyanidins); Inhibition of KB, CAL‐27, MCF‐7, HT‐29, HCT116, DU145 and LNCaP cells growth and apoptosis induction (blackberry, black raspberry, blueberry, cranberry, red raspberry and strawberry proanthocyanidins);; Decrease in of UVB‐induced immune suppression in mice with induction of IL‐12 (Grape seed proanthocyanidins); Apoptosis induction and metastasis inhibition of 4 T1 murine mammary cancer cells (Grape seed proanthocyanidins); Inhibition of induced mammary tumours in Sprague–Dawley rats (Grape seed proanthocyanidins); In vitro and in vivo inhibition of HT29 cell growth (Grape seed proanthocyanidins); Inhibition of prostate tumour growth and progression in TRAMP mice (Grape seed proanthocyanidins);.	Gollucke et al., 2013 Nile and Park, 2014 Skrovankova et al., 2015 Ouédraogo et al., 2011 Sieniawska, 2015 Turati et al., 2015
Antimicrobial	Inhibition of E. coli adherence to uroepithelium (Cranberry proanthocyanidins); Activity against Staphylococcus aureus, Candida albicans and Campylobacter jejuni (Ellagitannins); Antiherpetic activity (hydrolyzable tannins); Inhibition of cytopathic effects of HIV (hydrolyzable tannins); Inhibition of HIV‐antigen expression in human lymphotropic virus type I‐positive MT‐4 cells (hydrolyzable tannins); Activity against Helicobacter pylori (hydrolyzable tannins).	Marín et al., 2015 Nile and Park, 2014 Sieniawska, 2015 de Jesus, 2012
Anti‐nutrient	Inhibition of gastrointestinal enzymes (Proanthocyanidins); Reducing capacity on Cr, Fe and Cu with alteration of their absorption (Proanthocyanidins); Modulation of chronic inflammatory bowl diseases (Procyanidin B3).	Nile and Park, 2014 Sieniawska, 2015 Li et al., 2012 Dias et al., 2016
Cardioprotective	Hypocholesterolemic effects (Proanthocyanidins); Preventing myocardial ischaemic injury in adult rats (Proanthocyanidins); Cardioprotection in an experimental model of ischaemia–reperfusion damage (Proanthocyanidins); Anti‐atherosclerosi effect due to inhibition of differentiation of monocyte to macrophages (Oligomeric proanthocyanidins isolated from Crataegus oxyacantha L.); Protective effect on doxorubicin‐induced cardiac toxicity in rats (Grape‐seed proanthocyanidins); Suppression of doxorubicin‐induced electrocardiographic and biochemical changes (Grape‐seed proanthocyanidins); Protection against acute ischaemic brain damage in rats (Proanthocyanidins); Vascular protective effects (Procyanidin B2); Improved serum antioxidant status and decreased serum C‐reactive protein and plasma homocysteine concentrations (Proanthocyanidins); Decreased systolic and diastolic blood pressure (Grape‐wine proanthocyanidins).	Blumberg et al., 2013 Wang et al., 2014 Holt et al., 2012 Guler et al., 2011 Mohana et al., 2015 Ammar et al., 2013 Yunoki et al., 2014 Yang et al., 2013
Anti‐diabetic and anti‐obesity	Inhibition of salivary and pancreatic α‐amylase and α‐glucosidase activity (Hydrolyzable tannins and proanthocyanidins); Stimulation of glucose uptake and glycogen and lipid synthesis (hydrolyzable tannins and proanthocyanidins); Reduced plasmatic insulin and improved homeostatic model assessment (HOMA) index (hydrolyzable tannins and proanthocyanidins); Modulation of the active glucagon‐like peptide‐1 (GLP‐1) levels (hydrolyzable tannins and proanthocyanidins); Hypocholesterolemic effect (tannin‐rich fibre); Acute effects on postprandial lipaemia, vascular function and blood pressure (Pomegranate ellagitannins); Insulinomimetic properties GLUT4 mediated (Grape seed proanthocyanidins); Insulin anabolic‐like and lipostabilizer properties (Grape seed proanthocyanidins); Inhibition of diabetes‐induced cataract formation in rats (Cacao proanthocyanidins); Increased antioxidant enzyme activities, induction of metal chelation activity, reduced resistin formation, and inhibition or activation of transcriptional factors such as NF‐kB and PPARɣ (Proanthocyanidins).	Gonzalez‐Abuin et al., 2015 Banihani et al., 2013 Pinent et al., 2012 Gato et al., 2013 Mathew et al., 2012 Kooti et al., 2016 Cascaes et al., 2015 Cock, 2015 Stohs and Ray, 2015 Salvadó et al., 2015