Structural elucidation of the ellagitannin with a molecular weight of 2038 isolated from strawberry fruit (Fragaria ananassa Duch.) and named fragariin A

摘要

The structure of the ellagitannin (ET) with a molecular weight (MW) of 2038 isolated from strawberry fruit was elucidated on the basis of mass spectrometry data and nuclear magnetic resonance studies, with the newly determined compound being named fragariin A. Similarly to the main strawberry ET, agrimoniin (MW 1870), fragariin A was shown to contain a bis-HHDP-glucose moiety (MW 784). It exhibited the same three fragmentation ions with m/z 1567, 1265 and 633, arising from the detachment of consecutive hexahydroxydiphenoyl (HHDP) units from the structure with MW 1870. Based on spectroscopic studies, it was found that, in the tested ET (MW 2038), a free gallic acid is connected by a DOG-type bond to the 4,6-HHDP unit of the second glucose moiety of agrimoniin.