Revised Structures of Gambiriins A1, A2, B1, and B2, Chalcane-Flavan Dimers from Gambir (Uncaria gambir Extract)

Shoko Taniguchi; Kayo Kuroda; Kou-ichi Doi; Masahiro Tanabe; Takashi Shibata; Takashi Yoshida; Tsutomu Hatano

doi:10.1248/cpb.55.268

Regular Articles

Revised Structures of Gambiriins A1, A2, B1, and B2, Chalcane-Flavan Dimers from Gambir (Uncaria gambir Extract)

Shoko Taniguchi, Kayo Kuroda, Kou-ichi Doi, Masahiro Tanabe, Takashi Shibata, Takashi Yoshida, Tsutomu Hatano

Author information

Keywords: gambir, Uncaria gambir, chalcane-flavan dimer, catechin, gambiriin

JOURNAL FREE ACCESS

2007 Volume 55 Issue 2 Pages 268-272

DOI https://doi.org/10.1248/cpb.55.268

Details

Abstract

Gambir, the aqueous extract from Uncaria gambir (Rubiaceae), has been used as an astringent medicine in Asian countries. Investigation of the constituents in the extract led to the isolation of four chalcane-flavan dimers, gambiriin A1 (6), A2 (7), B1 (8), and B2 (9), in addition to (+)-catechin (1), (+)-epicatechin (2), and dimeric proanthocyanidins, procyanidin B1 (3), procyanidin B3 (4), and gambiriin C (5). The spectroscopic and chemical data obtained in the present study indicated that their previously proposed structures 6a, 7a, 8a, and 9a should be revised to 6, 7, 8, and 9, respectively.

Corresponding author

Register with J-STAGE for free!