Tannins and Related Compounds: CXIX: Samarangenins A and B, Novel Proanthocyanidins with Doubly Bonded Structures, from Syzygium samarangens and S: Aqueum

Abstract

Two proanthocyanidins named samarangenins A (1) and B (2) have been isolated, together with a variety of flavan-3-ols, proanthocyanidins and hydrolyzable and complex tannins, from the leaves of Syzygium samarangens (blume) merr.et perry and S. aqueum (burm f.) alston (= Eugenia aquea burm.) (Myrtaceae). Compounds 1 and 2 were characterized on the basis of spectroscopic and chemical evidence as novel dimeric proanthocyanidins, in which two flavanoid units are doubly linked through ether and carbon-carbon bonds. © 1992, The Pharmaceutical Society of Japan. All rights reserved.