Abstract
A chemical examination of the bark of Cinnamomum cassia( ?? ?? ?? ?? : Lauraceae) has led to the isolation of three flavan-3-ol glucosides (1-3) and three oligomeric procyanidins (4-6) named cinnamtannins A2-A4, together with (-)-epicatechin(7), procyanidins B-2 (8), B-5 (9) and C-1 (11), and a doubly-linked proanthocyanidin (10). On the basis of chemical and spectroscopic evidence, compounds 1-3 were characterized as (-)-epicatechin 3-O-, 8-C- and 6-C-β-D-glucopyranosides, respectively, while compounds 4-6 were shown to be tetrameric, pentameric and hexameric procyanidins, respectively, consisting exclusively of (-)-epicatechin units linked linearly through C(4β)-C(8) bonds.
