Dimeric ellagitannins from Alnus japonica

Article abstract of DOI:10.1016/0031-9422(92)83642-C

Two new hydrolysable tannins, alnusjaponins A and B, were isolated from the leaves of Alnus japonica, along with 12 known hydrolysable tannins and related compounds, namely 5-O-galloyl-(-)-shikimic acid, 2,3-(S)-hexahydroxydiphenoyl-d-glucose, 4,6-di-O-galloyl-d-glucose, 1,4-di-O-galloyl-β-d-glucose, 4,6-(S)-valoneoyl-d-glucose, strictinin, gemin D, pedunculagin, praecoxin A, flosin A, stachyurin and casuarinin. The structures of alnusjaponins A and B were elucidated on the basis of spectral and chemical evidence as dimeric ellagitannins consisting of pedunculagin and strictinin moieties in which the mode of linkage is different.