C C C C C TANNINS: Current knowledge of biological properties and health effects. Are high molecular weight compounds addressed? José Serrano, Riitta Puupponen-Pimiä, Andreas Dauer, Anna-Marja Aura and Fulgencio Saura- Calixto Universidad Complutense de Madrid, Spain VTT Technical Research Center, Finland Hexal Pharmaforschung GMBH, Germany Consejo Superior de Investigaciones Científicas, Spain
C C C C C Term first used in 1796 Tannins-History Tannery Industry Nutrition Science, 1960 Antinutritional point of view (e.g. seeds like legumes) Mineral absorption Protein precipitation Nutrition nowadays Bioactive compound Possible health effect
C C C C C Tannins-Disease Diabetes Mellitus Antimicrobial and antiviral properties Matsui et al, 2001 Broadhurst et al, 2000 Pinent et al, 2005 Tannins Chung et al, 1993 Scalbert, 1991 De Bruyne et al, 1999 Howell et al, 1998 Howell, 2002 Cancer Yu et al, 1987 Yoshida et al, 1995 Dolara et al, 2005 Neto, 2007. Cardiovascular disease Rasmussen et al, 2005 (review)
C C C C Dietary polyphenols C Benzoic acids and simple phenols Cinnamic acids Flavonoids (monomers) Flavones Isoflavones Flavanones Anthocyanins Stilbenes Coumarins Tannins (dimers to 30000 D MW) Condensed tannins Proanthocyanidins Propelargonins Prodelphinidins Hydrolysable tannins Ellagitannis Gallotannins Lignans and lignin 39,056 references (Medline) 4,504 references (Medline) The amount of tannins in our diet may be higher than the amount of flavonoids
C C C C C Flavonoids intake US population Prior y Gu, 2005 24.6 mg/day Flavonoids vrs Tannins intake Proanthocyanidins intake US population Prior y Gu, 2005 DP between 2-10 53.6 mg/day High molecular weight proanthocyanidin intake Spanish population Saura-Calixto et al, 2007 450 mg/day
C C C C C Tannins - Definition Chemical property Bate-Smith & Swain, 1962 Polyphenolic compounds with high molecular weight (between 500 to over 3000) Water soluble? Capacity for protein precipitation Defined chemical structure Gallotannins Monomer gallic acid Ellagitannins Monomer hexahydroxydiphenic acid Proanthocyanidins Monomer flavonoids Complex tannins? Phlorotannins Analysis?
C C C C C Tannins - Analysis Extraction (aqueous-organic solvents) Extracts Relative low molecular weight Grade polimerization 2-10 HPLC-MS MALDI-TF-MS Residue High molecular weight Associated to cell wall polysaccharides Associated to other dietary components Hydrolisis and further quantification of monomers What about the bioavailability?
C C C C C Content Growth & Harvesting Effects of storage and processing Tannins - Bioavailability Bioaccessibility (availability in the gut lumen) Absorption (cellular uptake)
C C C C C Content Growth & Harvesting Tannins - Bioavailability Proanthocyanidins US Deparment of Agriculture Grade of polymerization 2-10 www.nal.usda.gov/fnic/foodcomp/data/pa/pa.html Hydrolysable tannins Gallotannins Woody and herbaceous dicotyledons Ellagitannins Hamamelidae, Dilleniidae, Rosidae Literature data on the content and composition of dietary tannins are partial and insufficient to determine dietary intakes
C C C C C Effects of storage and processing Tannins - Bioavailability The tannin content in food is affected by storage and thermal processes Significant reductions are observed Storage time Temperature 4 days (Mullen et al, 2004) 12 months (Nohynek et al, 2006) 9 months (Hong et al, 2004) 3 months (Salminen, 2003) Drying process (Prior & Gu, 2005) Canning (Fuleki et al, 2003) Baking (Awika et al, 2003) Hot pressing 60 ºC (Fuleki et al, 2003) Domestic cooking (Sharma et al, 1992) ther processes Dehulling (seed coat) (Agudelo et al, 1997) Soaking (Mulimani et al, 1994) Germination (Sharma et al, 1992) However, it is not clear whether tannins are degraded during thermal processes or are polymerized to more highly polymerized compounds, which could result in incomplete extraction or quantification.
C C C C C Bioaccessibility Tannins - Bioavailability Proanthocyanidins Small Intestine Rios et al, 2002 Saura-Calixto et al, 2007 Large intestine Kunhle et al, 2000 Deprez et al, 2000 Goñi et al, 2005 Jenner et al, 2005 Hydrolysable tannins Daniel et al, 1991 Saura-Calixto et al, 2007 Krumholz et al, 1988 Cerda et al, 2003 Cerda et al, 2004 16 metabolites for PA dimer, trimer and polymers Phenyl acetic, phenyl propionic, phenylbutyric, phenyl valeric HT: gallic acid, pyrogallol, phloroglucinol,acetate, butyrate Punicalagin to Urolithin B Several compounds produced by colonic microflora fermentation
C C C C C Absorption Tannins - Bioavailability Small intestine Proanthocyanidins Not absorbed (dimers?) Hydrolysable tannins Posible absorption of gallic acid and hexahydroxydiphenic acid/ellagic acid Large intestine Microflora metabolites found in plasma and urine No data about fermentation metabolites biological effects
C C C C C Tannins - Bioavailability Is it necessary to be bioavailable to exert biological effects? 1 Local effects in gut lumen Antioxidant capacity Scavenging capacity Bacterial metabolism modulator Pro-carcinogen formation inhibitor 2 Intracellular signalling pathways in gut epithelial cells 3 Genetic modulator?
C C C C C Tannins Core of CST926 action Which are the best candidates for effects on gene regulation? Few studies available, principally in cell culture (hepatocytes, macrophages), but tannins are not bioavailable. Which are the best sources in daily diet (depending on availability across countries)? Fruit, chocolate and legumes for proanthocyanidins. Berries, legumes, nuts, green leafy vegetables for hydrolysable tannins. How bioavailable are the selected bioactive plant compounds? Low bioavailability, however low bioavailability not always implies low biological effect. (Local effects in gut lumen) How is bioavailability affected by (novel or improved) processing/preparation technologies? In general terms, the content is reduced with thermal process and storage. However, it is not clear whether tannins are degraded during thermal processes or are polymerized to more highly polymerized compounds, which could result in a low bioavailability.
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