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

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28 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)268-272
Number of pages5
JournalChemical and Pharmaceutical Bulletin
Volume55
Issue number2
DOIs
Publication statusPublished - Feb 1 2007

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Keywords

  • Catechin
  • Chalcane-flavan dimer
  • Gambir
  • Gambiriin
  • Uncaria gambir

ASJC Scopus subject areas

  • Chemistry(all)
  • Drug Discovery

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