Tannins And Related Compounds. LXXXIII. Isolation And Structures of Hydrolyzable Tannins, Phillyraeoidins A—E From Quercus Phillyraeoides

Abstract

A chemical examination of the leaves of Quercus phillyraeoides A. gray(Fagaceae) has led to the isolation of five new tannins, phillyraeoidins A—E (27—31), together with twenty-six structurally known tannins and related compounds including gallotannins (1,2), ellagitannins (3—14), proanthocyanidins (15—17), complex tannins (18—21) and simple phenol glucoside gallates (22—26). On the basis of spectroscopic and chemical evidence, the structures of phillyraeoidins A—D have been established as dimeric hydrolyzable tannins in which two glucose units are linked through a valoneayl ester bond, while phillyraeoidin E was characterized as l,2,3,6-tetra-0-galloyl-4-valoneayl(lactone)-/?-D-glucose. © 1989, The Pharmaceutical Society of Japan. All rights reserved.