Tannins of Tamaricaceous Plants. III. New Dimeric Hydrolyzable Tannins from Reaumuria hirtella

Abstract

Four new dimeric hydrolyzable tannins, hirtellins C, D, E and F, besides previously reported hirtellins A and B, have been isolated from the leaf extract of Reaumuria hirtella Jaub. et sp. (Tamaricaceae). Macrocyclic structures, 1 and 12, having both dehydrodigalloyl (DHDG) and isodehydrodigalloyl (isoDHDG) groups as the connecting units between monomers, were respectively assigned for hirtellin C and F, based on chemical methods, two-dimensional nuclear magnetic resonance measurement and other spectroscopic analyses. Hirtellin D (7) was characterized as an isomer of hirtellin F (12). Hirtellin E (15), having a dehydrotrigalloyl (hellinoyl) group, was characterized as an analog of hirtellin B. © 1993, The Pharmaceutical Society of Japan. All rights reserved.