Ellagitannins (a class of secondary metabolites) are a type of polyphenols characterised by biaryl-linked Galloyl groups (from
Potentillin is a monomeric ellagitannin and has an α-glycosyl linkage. It consists of a glucose molecule (shown in red). Surrounding the glucose unit are four more Gallic Acid moieties (galloyl groups, shown in blue, apart from the hydroxyl groups). The galloyl groups are also linked together in pairs, apart from a lone one on the right. Potentillin has been found in
It is interesting to note that Pedunculagin, another monomeric ellagitannin with one less galloyl group than Potentillin, is also found in many members of the same plant family. Pedunculagin exhibits anti-bacterial activity against Helicobacter pylori.
It can be seen that Agrimoniin is another ellagitannin and is a dimer of two Potentillin molecules. Agrimoniin consisting of two identical Potentillin molecules fused together by an oxygen bridge (central red 'O'). Your author has had to bend the molecule slightly in order to more clearly show the near bi-lateral symmetry (the way that oxygen bridge links the two identical units is the only part that is asymmetrical).
Agrimoniin is the very first dimeric ellagitannin to be discovered. Agrimoniin was found in Agrimony, but is now known to also be present in
Strawberry, and some other members of the Rose Family, especially those belonging to the Genera Agrimonia, Potentilla and Fragaria. It has anti-tumour properties amongst a host of other beneficial attributes.