Tannins and Related Compounds. LXI.1) Isolation and Structures of Novel Bi- and Triflavanoids from the Leaves of Cassia fistula L.

Abstract

Together with (—)-epiafzelechin (1) and its 3-0-glucoside (4), (—)-epicatechin (2) and procyanidin B-2 (3), seven new biflavanoids (5—7, 9—12) and two triflavanoids (8, 13) have been isolated from the leaves of Cassia fistula L. (Leguminosae). On the basis of chemical and spectroscopic evidence, the structures of 5—8 were established to be proanthocyanidins each having (—)-epiafzelechin unit(s) in the molecule, while 9—13 were shown to consist of (2S)-7, 4’-dihydroxyflavan and (—)-epiafzelechin units. © 1988, The Pharmaceutical Society of Japan. All rights reserved.