Tannins and Related Polyphenols of Euphorbiaceous Plants. IX: Hydrolyzable Tannins with 1CAr Glucose Core from Phyllanthus flexuosus muell: Arg

Abstract

Four new hydrolyzable tannins (phyllanthusiins A—D), a new polyphenol of related structure (phyllanthusiin E), and eight known polyphenols have been isolated from the leaves of Phyllanthusflexuosus. flexuosus. On the basis of the spectroscopic methods including 1H--“C long-range two-dimensional nuclear magnetic resonance techniques, phyllanthusiins A (9) B (12) and C (14), were characterized as oxidative metabolites of geraniin, each having a different new acyl group biogenetically formed via an oxidative cleavage of the dehydrohexahydroxydiphenoyl group, on the 1C4 glucopyranose core. Phyllanthusiin D (15) was determined to be a condensate of geraniin with acetone, and phyllanthusiin E (16), was an oxidized congener of ellagic acid. © 1992, The Pharmaceutical Society of Japan. All rights reserved.