Tannins of Tamaricaceous Plants. VI.1) Four New Trimeric Hydrolyzable Tannins from Reaumuria hirtella and Tamarix pakistanica

Abstract

Two novel ellagitannin trimers, hirtellins T2 (1) and T3 (25), besides previously reported hirtellin T1(28), have been isolated from the leaves of Reaumuria hirtella jaub. et sp. (Tamaricaceae). Hirtellin T2 has a 36-membered macro-ring structure (1) with three dehydrodigalloyl (m-GOG) units connecting monomers, while hirtellin T3 (25) possesses one m-GOG and one hellinoyl (m-GO-m-GOG) unit forming a rigid macro-ring, as found in hirtellin B. Two new tannins, tamarixinins T1 (26) and T2 (T2a + T2b) (27), having a w-GOG and/or isodehydrodigalloyl (p-GOG) unit were also isolated from the flowers of Tamarix pakistaniea quaiser. The structures of these new ellagitannin trimers were elucidated based on chemical methods and spectroscopic analyses, including two-dimensional nuclear magnetic resonance measurements. © 1994, The Pharmaceutical Society of Japan. All rights reserved.