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.
^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
^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.
PMID23656584.