TANNINS AND RELATED-COMPOUNDS .108. ISOLATION AND CHARACTERIZATION OF NOVEL COMPLEX TANNINS (FLAVANO-ELLAGITANNINS), ANOGEISSININ AND ANOGEISSUSIN-A AND ANOGEISSUSIN-B, FROM ANOGEISSUS-ACUMINATA (ROXB EX DC) GUILL ET PERR VAR LANCEOLATA WALL EX CLARKE

Three novel complex tannins (flavano-ellagitannins), anogeissinin (9) and anogeissusins A (10) and B (11), have been isolated from the bark of Anogeissus acuminata (ROXB, ex DC.) GUILL. et PERR. var. lanceolata WALL. ex CLARKE (Combretaceae), together with eight known C-glycosidic hydrolyzable tannins. On the basis of spectroscopic and chemical evidence, anogeissinin (9) was shown to have two C-glycosidic ellagitannin (vescalagin) moieties connected to the C-6 and C-8 positions in the (+)-catechin moiety, while anogeissusins A (10) and B (11) have structures in which the dimeric C-glycosidic ellagitannin, castamollinin (8), is attached to the C-8 position of the (+)-catechin and (+)-gallocatechin moieties, respectively.