Tannins and related compounds. Part 3. A new phenolic acid, sanguisorbic acid dilactone, and three new ellagitannins, sanguiins H-1, H-2, and H-3, from Sanguisorba officinalis

Abstract

A new phenolic acid, sanguisorbic acid dilactone, and three new ellagitannins, sanguiins H-1, H-2, and H-3, have been isolated from the underground parts of Sanguisorba officinalis L. (Rosaceae). On the basis of chemical and spectroscopic evidence, sanguisorbic acid dilactone has been shown to possess a trimeric gallic acid structure and to be a structural isomer of valoneaic acid dilactone. Similarly, sanguiins H-1 and H-2 have been characterized as 1,6-digalloyl-2,3-(4,4′,5,5′,6,6′-hexahydroxydiphenoyl)glucose and 1-galloyl-2,4-(4,4′,5,5′,6,6′-hexahydroxydiphenoyl)-3,6-sanguisorboylglucose, respectively. Sanguiin H-3 has been shown mainly by spectroscopic data and analyses of partial hydrolysates to have a novel dimeric structure containing 2,3-hexahydroxydiphenoyl)glucose and sanguiin H-2 moieties.