Ellagitannin
The ellagitannins are a diverse class of hydrolyzable tannins, a type of polyphenol formed primarily from the oxidative linkage of galloyl groups in 1,2,3,4,6-pentagalloyl glucose. Ellagitannins differ from gallotannins, in that their galloyl groups are linked through C-C bonds, whereas the galloyl groups in gallotannins are linked by depside bonds.[1]
Ellagitannins contain various numbers of hexahydroxydiphenoyl units, as well as galloyl units and/or sanguisorboyl units bounded to sugar moiety. In order to determine the quantity of every individual unit, the hydrolysis of the extracts with trifluoroacetic acid in methanol/water system is performed. Hexahydroxydiphenic acid, created after hydrolysis, spontaneously lactonized to ellagic acid, and sanguisorbic acid to sanguisorbic acid dilactone, while gallic acid remains intact.[2]
Ellagitannins generally form macrocycles, whereas gallotannins do not.
Examples
- Castalagin
- Castalin
- Casuarictin
- Grandinin
- Oenothein B from Willowherbs (Epilobium spp.)
- Roburin A
- Tellimagrandin II
- Terflavin B
- Vescalagin
- Pomegranate ellagitannins, many compounds
Metabolism
Degradation
Urolithins, such as urolithin A, are microflora human metabolites of dietary ellagic acid derivatives.[3]
Natural occurrences
Ellagitannins are reported in dicotyledoneous angiospermes, and notably in species in the order Myrtales, such as the pomegranate.[4][5]
See also
Other links
References
- ^ Landete, J.M. (2011). "Ellagitannins, ellagic acid and their derived metabolites: A review about source, metabolism, functions and health". Food Research International. 44 (5): 1150–1160. doi:10.1016/j.foodres.2011.04.027.
- ^ Structural diversity and antimicrobial activities of ellagitannins. T. Yoshida, Ts. Hatano, H. Ito, T. Okuda, S. Quideau (Ed.), Chemistry and Biology of Ellagitannins, World Scientific Publishing, Singapore (2009), pages 55–93
- ^ Davis, CD; Milner, JA (Oct 2009). "Gastrointestinal microflora, food components and colon cancer prevention". J Nutr Biochem. 20 (10): 743–52. doi:10.1016/j.jnutbio.2009.06.001. PMC 2743755. PMID 19716282.
- ^ Yoshida, Takashi (2010). "Structural Features and Biological Properties of Ellagitannins in Some Plant Families of the Order Myrtales". International Journal of Molecular Sciences. 11 (1): 79–106. doi:10.3390/ijms11010079. PMC 2820991. PMID 20162003.
- ^ Gómez-Caravaca, A. M.; Verardo, V; Toselli, M; Segura-Carretero, A; Fernández-Gutiérrez, A; Caboni, M. F. (2013). "Determination of the major phenolic compounds in pomegranate juices by HPLC−DAD−ESI-MS". Journal of Agricultural and Food Chemistry. 61 (22): 5328–37. doi:10.1021/jf400684n. PMID 23656584.
Further reading
- Quideau, Stéphane (editor). Chemistry and Biology of Ellagitannins: An Underestimated Class of Bioactive Plant Polyphenols, 2009, World Scientific Publishing. Table of Contents[permanent dead link]. Preface[permanent dead link]. Chapter 1.
External links
- Tannin Chemistry (Tannin Handbook, Copyright 1998, 2002, 2011, Ann E. Hagerman)