Isoterchebulin and 4,6-O-isoterchebuloyl-D-glucose, novel hydrolyzable tannins from Terminalia macroptera.
Conrad, Juergen; Vogler, Bernhard; Reeb, Sabine; Klaiber, Iris; Papajewski, Stefan; Roos, Gudrun; Vasquez, Erlinda; Setzer, Mary C.; Kraus, Wolfgang.
Journal of Natural Products (2001), 64(3), 294-299.

Abstract

Two new hydrolyzable tannins, isoterchebulin (I) and 4,6-O-isoterchebuloyl-D-glucose (II), together with six known tannins, (III-VIII), were isolated from the bark of Terminalia macroptera. Their structures were elucidated by extensive 1D and 2D NMR studies, MS, and chem. transformations. Biol. activities of all compds. were evaluated against the snail Biomphalaria glabrata, the bacteria Bacillus subtilis and Pseudomonas fluorescens, the nematode Caenorhabditis elegans, and four cancer cell lines (Hep G2, MCF-7/S, MDA-MB-231, and 5637 cells). All compds. except III showed antimicrobial activities against B. subtilis (MIC 8-64 ?g/mL), whereas only I was active against C. elegans (100 ?g/mL) and B. glabrata (LC100=60 ?g/mL). III and VIII were toxic against 5637 cells with LC50=84.66 and 41.40 ?M, resp.