Tannins of rosaceous medicinal plants. Part 2. Gemins A, B, and C, new dimeric ellagitannins from Geum japonicum

Abstract

Three novel dimeric hydrolysable tannins, gemins A, B, and C, have been isolated from the leaves of Geum japonicum(Thunb.) and their structures, which have α- and β-glucose cores linking through a dehydrodigalloyl group, have been elucidated from spectral and chemical evidence