Identification of urinary and intestinal bacterial metabolites of ellagitannin geraniin in rats

Hideyuki Ito, Ayumu Iguchi, Tsutomu Hatano

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81 Citations (Scopus)


Hydrolyzable tannins, including ellagitannins, occur in foods such as berries and nuts. Various biological activities, including antioxidant, antiviral, and antitumor activities, have been noted and reported for ellagitannins, but the absorption and metabolism of purified ellagitannins are poorly understood. We describe herein the characterization of urinary and intestinal microbial metabolites in rats after the ingestion of ellagitannins. Urine samples were collected after oral administration of ellagitannins such as geraniin (1), corilagin (2), and their related polyphenols. The suspension of rat intestinal microflora was anaerobically incubated with ellagitannins. Each sample was separated by column chromatography and/or preparative HPLC to give seven metabolites, M1-M7. The structures of these metabolites were determined on the basis of spectroscopic data and chemical evidence. These compounds, except for M1, were characterized as ellagitannin metabolites for the first time. Furthermore, among four major metabolites (M1-M4) in urine, M2 showed an antioxidant activity comparable to intact geraniin and related polyphenols.

Original languageEnglish
Pages (from-to)393-400
Number of pages8
JournalJournal of agricultural and food chemistry
Issue number2
Publication statusPublished - Jan 23 2008


  • Brevifolincarboxylic acid
  • Corilagin
  • Ellagic acid
  • Ellagitannin
  • Gallic acid
  • Geraniin
  • Intestinal microflora
  • Metabolites
  • Radical scavenger
  • Urine

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)


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