Tannins and related polyphenols of rosaceous medicinal plants. IV. Roxbins A and B from Rosa roxburghii fruits.

Abstract
From the unripe fruits of Rosa roxburghii TRATT., two new hydrolyzable tannins, roxbin A (1) (a dimeric ellagitannin) and roxbin B (9), were isolated along with rugosin F (2), pedunculagin (3). casuarictin(4), alnusiin (5), stachyurin (6), tellimagrandin II (7), 2,3-O-(S)-hexahydroxydiphenoyl-D-glucose and ( + )-catechin. The structures of new tannins were elucidated on the basis of chemical and spectral evidence.