Synthesis of (-)-[4-3H]epigallocatechin gallate and its metabolic fate in rats after intravenous administration

Toshiyuki Kohri, Fumio Nanjo, Masayuki Suzuki, Ryota Seto, Natsuki Matsumoto, Mana Yamakawa, Hiroshi Hojo, Yukihiko Hara, Dhimant Desai, Shantu Amin, C. Clifford Conaway, Fung Lung Chung

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90 Scopus citations

Abstract

Because a great deal of attention has been focused on the metabolism of (-)-epigallocatechin gallate (EGCg), quantitative analysis of this compound is required. For this purpose we developed a method of chemical synthesis of [4-3H]EGCg. Synthesized [4-3H]EGCg showed 99.5% radiochemical purity and a specific activity of 13 Ci/mmol. To clarify the excretion route of EGCg, the radioactivity levels of bile and urine were quantified after intravenous administration of [4-3H]EGCg to bile-ductcannulated rats. Results showed that the radioactivity of the bile sample excreted within 48 h accounted for 77.0% of the dose, whereas only 2.0% of the dose was recovered in the urine. The excretion ratio of bile to urine was calculated to be about 97:3. These results clearly showed that bile was the major excretion route of EGCg. Time-course analysis of the radioactivity in blood was also performed to estimate the pharmacokinetic parameters following intravenous administration of [4-3H]EGCg. In addition, EGCg metabolites excreted in the bile within 4 h after the intravenous dose of [4-3H]EGCg were analyzed by HPLC. The results showed that 4′,4′-di-O-methyl-EGCg was present in the conjugated form and made up about 14.7% of the administered radioactivity.

Original languageEnglish (US)
Pages (from-to)1042-1048
Number of pages7
JournalJournal of agricultural and food chemistry
Volume49
Issue number2
DOIs
StatePublished - Mar 6 2001

All Science Journal Classification (ASJC) codes

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

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