Ellagitannins

The chirality is the result of the limited free rotation around the axis of the C-C bond due to the two ester bonds between the galloyl residues and the 

The name ellagitannins is derived from ellagic acid (1.96), which is formed spontaneously from hexahydroxydiphenic acid (1.94/1.95) in aqueous solution via an intra-molecular esterification reaction. 

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Simple phenolics and their derivatives (benzoic, gallic, ellagic, gallotannins and ellagitannins), flavonoids and condensed tannins... 

Niemetz R, Gross GG (2005), Enzymology of gallotannin and ellagitannin biosynthesis , Phytochemistry, 66, 2001-2011. 

The most widely used method is based on the reaction between potassium iodate and hydrolyzable tannins (Hartzfeld and others 2002). This method provides a good estimate for gallotannins but underestimates the content of ellagitannins. 

Hydrolyzable tannins Ellagitannins Pomegranate juice Strawberry Blueberry Raspberry Blackberry Longan seed... 

Cerda B, Ceron JJ, Tomas-Barberan FA and Espin JC. 2003a. Repeated oral administration of high doses of pomegranate ellagitannin punicalagin to rats for 37 days is not toxic. J Agric Food Chem 51(11) 3493—3501. 

Hartzfeld PW, Forkner R, Hunter MD and Hagerman AE. 2002. Determination of hydrolyzable tannins (gal-lotannins and ellagitannins) after reaction with potassium iodate. J Agric Food Chem 50(7) 1785—1790. 

SILVA, O, GOMES, E.T., WOLFENDER, J.L., MARSTON, A., HOSTETTMANN, K., Application of high performance liquid chromatography coupled with ultraviolet spectroscopy and electrospray mass spectrometry to the characterisation of ellagitannins from Terminalia macroptera roots, Pharm. Res., 2000,17, 1396-1401. 

The separation characteristics of unmodified silica, diol, cyano, cellulose and RP-18 stationary phases were compared for the analysis of ellagitannins, gallotannins and flavonoid glycosides in the aerial parts of Erodium cicutarum (Geraniaceae) (stork s bill). Its decoction has been used in cases of dysentery, fever, wounds and worm infections. The air-dried and powdered plant material (300 g) was extracted three times with water-acetone (1 1, v/v) at ambient temperature. The collected extract was filtered and concentrated. The aqueous phase was acidified to pH 3 with formic acid and separated in an ODS column. Polphenols... 

Dry heat treatment of oak resulted in a decrease in the amount of ellagitannins and a simultaneous increase in ellagic acid the lignan lyoniresinol was unaffected by heat treatment... 

Extracts of plants have been used as insecticides by humans since before the time of the Romans. Some of these extracts have yielded compounds useful as sources (e.g., pyrethrins, rotenoids, alkaloids), others as models (e.g., pyrethrins, physostigmine) of commercial insecticides. Recent technological advances which facilitate the isolation and identification of the bioactive constituents of plants should ensure the continued usefulness of plant compounds in commercial insect control, both as sources and models of new insect control agents and also as components in host plant resistance mechanisms. The focus in this paper will be on several classes of compounds, including limonoids, chromenes, ellagitannins, and methyl ketones, which were found to be components of the natural defenses of both wild and cultivated plants and which may be useful in commercial insect control. 

Figure 2. Structure of an ellagitannin, l-0-galloyl-2,3 4,6-di-0-hexahy-droxydiphenoyl-/ -D-glucose (casuarictin).

Little knowledge also exists on the mechanisms involved in the biosynthesis of the characteristic structures of gallotannins and ellagitannins, as will be briefly discussed below. 

O-hexahydroxydiphenoylglucose). These preliminary results indicate that rather specific oxidoreductases, and not the abovementioned very unspecific oxidases, are involved in the biosynthesis of ellagitannins. 

Chart 8.1.S Shikimates (skeletons) widespread on land (5max=57, av=43 5//ftnax=0.48, av=0.39). Tannins lignans epigallocathechin gallate (Asian black tea. Camellia sinensis L.) Kuntze, Theaceae, Ang. MI) procyanidins and prodelphinidins (widespread in plants) soluble hydrolyzable tannins gallotannin (myrobalan. East Indian trees, Terminalia spp., oak, Quercus spp., Lithocarpus spp., and sumac, Rhus spp.) ellagitannin (Myrtaceae). 

Tanaka, T. et al.. Tannins and related compounds. CXXIV. Five new ellagitannins, platycaryanins A, B, C, and D, and platycariin, and a new complex tannin, strobilanin, from the fruits and bark of Platycarya strobilacea Sieb. et Zucc., and biomimetic synthesis of C-glycosidic ellagitannins from glucopyranose-based ellagitannins, Chem. Pharm. Bull, 41, 1708, 1993. 

For a recent example of oxidative coupling to give ellagitannin type biaryls, see K. S. Feldman,... 

N.A. Potentilla anserina L. Ellagitannins, flavonoids, choline.99 Gargle for sore throats, remedy for diarrhea. 

Potentilla erecoa (L.) Rauschel. P. tormentilla (L.) Rauschel. Tannins, catechins, ellagitannins, phlobaphene." Gargle for throat infections, mouthwash for canker sores and infected gums. 

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