Based on the proposed structures, the two HHDP moieties of 1′ would arise from an intermolecular oxidative coupling between galloyl units in 1,2-di-O-galloyl-α/β-glucopyranose, while 2′ could similarly derive from 3,4,6-tri-O-galloyl-α/β-glucopyranose (Figure ). Ellagitannin dimers generally form via C-O linkages between the acyl moieties of monomeric units, 9 whereas C-C bond linkages between acyl groups are exceptionally rare. 10 Moreover, no naturally occurring ellagitannins bearing an intermolecular galloyl-to-galloyl C-C bond have been reported to date, and such linkages, if formed, would likely be hydrolytically labile, yielding an ellagic acid. Namely, these proposed dimeric structures are difficult to rationalize according to a biosynthetic point of view.