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MetaCyc Pathway: superpathway of hydrolyzable tannin biosynthesis
Inferred from experimentTraceable author statement to experimental support

Pathway diagram: superpathway of hydrolyzable tannin biosynthesis

If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.

Superclasses: BiosynthesisSecondary Metabolites BiosynthesisPhenylpropanoid Derivatives BiosynthesisHydrolyzable Tannins Biosynthesis

Some taxa known to possess this pathway include : Quercus robur, Quercus rubra, Rhus typhina, Tellima grandiflora

Expected Taxonomic Range: Viridiplantae

General Background

Hydrolyzable tannins (HT), divided in the two subclasses gallotannins (see gallotannin biosynthesis) and ellagitannins (see cornusiin E biosynthesis) are derivatives of pentagalloylglucose (1,2,3,4,6-penta-O-galloyl-β-D-glucopyranose) [Niemetz00]. The category 'hydrolyzable tannins' is based on the classical definition of Freudenberg [Freudenberg20] who distinguished condensed tannins (also referred to as proanthocyanins; flavonoid origin) and hydrolysable tannins (esters of gallic acid with typically β-D-glucose). That class of compounds belongs to the more general 'plant polyphenols' (synonym vegetable tannins) which have been intensively studied in the last few decades (reviewed in [Haslam89] [Haslam94] [Haslam98].

The name 'tannin' derived from the pronounced property of these compounds to precipitate proteins which has been used over the centuries for the tannery procedure to produce endurable leather from raw hides. Beside that, hydrolyzable tannins have many antimicrobial, antioxidant and antitumor properties used in human health care [Haslam96] and apply the varying amount of astringency as food components/phytonutrients [Beecher03]. Hydrolyzable tannins are widely distributed among plants but differ with regard to gallotannins (more restricted occurence) and ellagitannins (broad occurence) [Haddock82].

The mono- to penta-substituted esters being generated on the biogenetic way towards pentagalloylglucose are also referred to as 'simple' galloylglucoses in contrast to the 'complex' galloylglucoses produced as the result of further galloylation of pentagalloylglucose [Niemetz05]. However, that categorization does not indicate the tanning potential of the associated compounds.

About This Pathway


The biosynthesis towards pentagalloylglucose displays a high specificity with a defined metabolic sequence. The first step is the formation of β-glucogallin (1-O-galloyl-β-D-glucopyranose) from gallic acid catalyzed by the UDPG-dependent gallate-1-β-glucosyltransferase [Gross82, Gross83a]. This compound does not only function as the common acyl acceptor throughout the pentagalloylglucose biosynthetic pathway but exerts in addition a dual role as acyl donor indicating the characteristic of an energy-rich 'activated' compound [Gross83].

The further galloylation follows the metabolic sequence 1,6-digalloylglucose [Schmidt87a], 1,2,6-trigalloylglucose [Gross91], 1,2,3,6-tetragalloylglucose [Hagenah93] and finally 1,2,3,4,6-pentagalloylglucose [Cammann89]. The formation of 1,2,6-trigalloylglucose may also occur using an alternative route [Denzel91].


The oxidative steps from pentagalloylglucose to the dimeric cornusiin E via the monomeric ellagiotannin tellimagrandin II are catalyzed by two enzymes that belong to the group of p-diphenol: O2-oxidoreductases (EC also known as 'laccases' [Niemetz01a] [Niemetz03a] [Niemetz03]. The enzymes catalyzes the sterespecific phenolic coupling to produce the (S)-stereoconfiguration as observed in tellimagrandin II and cornusiin E, respectively.


The experimental data clearly indicate that the impressive number of gallotannins is produced following one general reaction type. Five enzymes catalyze the progressive galloylation of pentagalloylglucose towards penta-, hexa- and heptagalloylglucoses and even higher substituted galloylglucoses [Niemetz00, Hofmann90]. Although the enzymes are not very specific towards their substrates it was found on the basis of calculated catalytic efficiency that each of them had a preferred substrate (and major product) and therefore operates along a mainstream metabolic sequence [Niemetz05]. Those five galloyltransferases identified in sumac (also called galloyltransferase A to E) have been demonstrated to catalyze the various heptagalloylglucoses in this plant [Niemetz99, Niemetz98, Niemetz01, Frohlich02].

Subpathways: pentagalloylglucose biosynthesis, cornusiin E biosynthesis, gallotannin biosynthesis

Created 16-Feb-2007 by Foerster H, TAIR


Beecher03: Beecher GR (2003). "Overview of dietary flavonoids: nomenclature, occurrence and intake." J Nutr 133(10);3248S-3254S. PMID: 14519822

Cammann89: Cammann J, Denzel K, Schilling G, Gross GG (1989). "Biosynthesis of gallotannins: β-glucogallin-dependent formation of 1,2,3,4,6-pentagalloylglucose by enzymatic galloylation of 1,2,3,6-tetragalloylglucose." Arch Biochem Biophys 273(1);58-63. PMID: 2757399

Denzel91: Denzel K, Gross GG (1991). "Biosynthesis of gallotannins. Enzymatic 'disproportionation' of 1,6-digalloylglucose to 1,2,6-trigalloylglucose and 6-galloylglucose by an acyltransferase from leaves of Rhus typhina L." Planta, 184, 185-289.

Freudenberg20: Freudenberg K (1920). "Die Chemie der naturlichen Gerbstoffe." Springer Verlag, Berlin.

Frohlich02: Frohlich B, Niemetz R, Gross GG (2002). "Gallotannin biosynthesis: two new galloyltransferases from Rhus typhina leaves preferentially acylating hexa- and heptagalloylglucoses." Planta 216(1);168-72. PMID: 12430027

Gross82: Gross GG (1982). "Synthesis of β-glucogallin from UDP-glucose and gallic acid by an enzyme preparation from oak leaves." FEBS letters, 148(1), 67-70.

Gross83: Gross GG (1983). "Synthesis of Mono-, Di- and Trigalloyl-β-D-glucose by β-Glucogallin-Dependent Galloyltransferases from Oak Leaves." Z. Naturforsch., 38c, 519-523.

Gross83a: Gross GG (1983). "Partial purification and properties of UDP-glucose:vanillate 1-O-glucosyl transferase from Oak leaves." Phytochemistry, 22(10), 2179-2182.

Gross91: Gross GG, Denzel K (1991). "Biosynthesis of Gallotannins. β-glucogallin-dependent galloylation of 1,6-digalloylglucose to 1,2,6-trigalloylglucose." Z. Naturforsch., 46c, 389-394.

Haddock82: Haddock EA, Gupta RK, Al-Shafi SM, Layden K, Haslam E, Magnolato D (1982). "The metabolism of gallic acid and hexahydroxydiphenic acid in plants: biogenetic and molecular taxonomic considerations." Phytochemistry, 21(5), 1049-1062.

Hagenah93: Hagenah S, Gross GG (1993). "Biosynthesis of 1,2,3,6-tetra-O-galloyl-β-D-glucose." Phytochemistry, 32(3), 637-641.

Haslam89: Haslam E (1989). "Plant polyphenols. Vegetable tannins revisited." Cambridge University Press, Cambridge - New York - New Rochelle - Melbourne - Sydney.

Haslam94: Haslam E, Cai Y (1994). "Plant polyphenols (vegetable tannins): gallic acid metabolism." Nat Prod Rep 11(1);41-66. PMID: 15206456

Haslam96: Haslam E (1996). "Natural polyphenols (vegetable tannins) as drugs: possible modes of action." J Nat Prod 59(2);205-15. PMID: 8991956

Haslam98: Haslam E (1998). "Practical polyphenolics. From structure to molecular recognition and physiological action." Cambridge University Press, Cambridge.

Hofmann90: Hofmann AS, Gross GG (1990). "Biosynthesis of gallotannins: formation of polygalloylglucoses by enzymatic acylation of 1,2,3,4,6-penta-O-galloylglucose." Arch Biochem Biophys 283(2);530-2. PMID: 2148866

Niemetz00: Niemetz R, Niehaus JU, Gross GG (2000). "Biosynthesis and biodegradation of complex gallotannins." In: Gross, GG., Hemingway, RW. and Yoshida, T. (eds.) Plant Polyphenols 2: Chemistry and Biology, 63-83. Kluwer Academic/Plenum Publishing Corporation, New York, Boston, Dordrecht, London, Moscow.

Niemetz01: Niemetz R, Gross GG (2001). "Gallotannin biosynthesis: β-glucogallin: hexagalloyl 3-O-galloyltransferase from Rhus typhina leaves." Phytochemistry 58(5);657-61. PMID: 11672728

Niemetz01a: Niemetz R, Schilling G, Gross GG (2001). "Ellagitannin biosynthesis: oxidation of pentagalloylglucose to tellimagrandin II by an enzyme from Tellima grandiflora leaves." Chem. Commun., 1, 35-36.

Niemetz03: Niemetz R, Gross GG (2003). "Ellagitannin biosynthesis: laccase-catalyzed dimerization of tellimagrandin II to cornusiin E in Tellima grandiflora." Phytochemistry 64(7);1197-201. PMID: 14599517

Niemetz03a: Niemetz R, Gross GG (2003). "Oxidation of pentagalloylglucose to the ellagitannin, tellimagrandin II, by a phenol oxidase from Tellima grandiflora leaves." Phytochemistry 62(3);301-6. PMID: 12620341

Niemetz05: Niemetz R, Gross GG (2005). "Enzymology of gallotannin and ellagitannin biosynthesis." Phytochemistry 66(17);2001-11. PMID: 16153405

Niemetz98: Niemetz R, Gross GG (1998). "Gallotannin biosynthesis: Purification of β-glucogallin: 1,2,3,4,6-pentagalloyl-β-D-glucose galloyltransferase from Sumac leaves." Phytochemistry, 49(2), 327-332.

Niemetz99: Niemetz R, Gross GG (1999). "Gallotannin biosynthesis: A new beta-glucogallin-dependent galloyltransferase from Sumac leaves acylating gallotannins at positions 2 and 4." J Plant Physiol, 155, 441-446.

Schmidt87a: Schmidt SW, Denzel K, Schilling G, Gross GG (1987). "Enzymatic synthesis of 1,6-digalloylglucose from β-glucogallin by β-glucogallin: β-glucogallin 6-O-galloyltransferase from Oak leaves." Z. Naturforsch., 42c, 87-92.

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Bors99: Bors W, Michel C (1999). "Antioxidant capacity of flavanols and gallate esters: pulse radiolysis studies." Free Radic Biol Med 27(11-12);1413-26. PMID: 10641736

Denzel88: Denzel K, Schilling G, Gross GG (1988). "Biosynthesis of gallotannins. Enzymatic conversion of 1,6-digalloylglucose to 1,2,6-trigalloylglucose." Planta, 176, 135-137.

Feldman99: Feldman KS, Sahasrabudhe K, Smith RS, Scheuchenzuber WJ (1999). "Immunostimulation by plant polyphenols: a relationship between tumor necrosis factor-α production and tannin structure." Bioorg Med Chem Lett 9(7);985-90. PMID: 10230625

Fujiki05: Fujiki H (2005). "Green tea: Health benefits as cancer preventive for humans." Chem Rec 5(3);119-32. PMID: 15889414

Grundhofer01: Grundhofer P, Niemetz R, Schilling G, Gross GG (2001). "Biosynthesis and subcellular distribution of hydrolyzable tannins." Phytochemistry 57(6);915-27. PMID: 11423141

Hadi00: Hadi SM, Asad SF, Singh S, Ahmad A (2000). "Putative mechanism for anticancer and apoptosis-inducing properties of plant-derived polyphenolic compounds." IUBMB Life 50(3);167-71. PMID: 11142343

Krajci87: Krajci I, Gross GG (1987). "Formation of gallotannins in callus cultures from oak (Quercus robur)." Phytochemistry, 26(1), 141-143.

Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Lazarowski03: Lazarowski ER, Shea DA, Boucher RC, Harden TK (2003). "Release of cellular UDP-glucose as a potential extracellular signaling molecule." Mol Pharmacol 63(5);1190-7. PMID: 12695547

Mittasch14: Mittasch J, Bottcher C, Frolova N, Bonn M, Milkowski C (2014). "Identification of UGT84A13 as a candidate enzyme for the first committed step of gallotannin biosynthesis in pedunculate oak (Quercus robur)." Phytochemistry. PMID: 24412325

Niemetz03b: Niemetz R, Schilling G, Gross GG (2003). "Biosynthesis of the dimeric ellagitannin, cornusiin E, in Tellima grandiflora." Phytochemistry 64(1);109-114. PMID: 12946409

Nishizawa83: Nishizawa M, Yamagishi T, Nonaka G, Nishioka I, Nagasawa T, Oura H (1983). "Tannins and related compounds. XII. Isolation and characterization of galloylglucoses from Paeoniae Radix and their effects on urea-nitrogen concentration in rat serum." Chem Pharm Bull (Tokyo) 31(8);2593-600. PMID: 6652813

Okuda00: Okuda T, Yoshida T, Hatano T (2000). "Correlation of oxidative transformations of hydrolyzable tannins and plant evolution." Phytochemistry 55(6);513-29. PMID: 11130661

Okuda89: Okuda T, Yoshida T, Hatano T (1989). "Ellagitannins as active constituents of medicinal plants." Planta Med 55(2);117-22. PMID: 2664829

Yang99a: Yang LL, Wang CC, Yen KY, Yoshida T, Hatano T, Okuda T (1999). "Antitumor activities of ellagitannins on tumor cell lines." Basic Life Sci 66;615-28. PMID: 10800466

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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