Tannins of Theaceous Plants. III. Camelliatannins A and B, Two New Complex Tannins from Camellia japonica L.

Abstract

Two new complex tannins, camelliatannins A (1) and B (2), were isolated from the leaves of Camellia japonica L. (Theaceae). The structures of these tannins, each consisting of a C-glucosidic ellagitannin and (-)-epicatechin (9), were established by means of chemical degradation, synthesis from casuariin (4) and 9, and rotating frame Overhauser enhancement spectroscopy (ROESY). Gemin D (3), 4, pedunculagin (5) and 2, 3-(S)-hexahydroxydiphenoyl-D-glucose (6) were also isolated from the leaves.