Theasinensin A, a Tea Polyphenol Formed from (-)-Epigallocatechin Gallate, Suppresses Antibiotic Resistance of Methicillin-Resistant Staphylococcus aureus

Tsutomu Hatano, Miwako Kusuda, Mami Hori, Sumiko Shiota, Tomofusa Tsuchiya, Takashi Yoshida

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29 Citations (Scopus)


When (-)-epigallocatechin gallate (EGCG), the main constituent of tea polyphenols, was kept in a neutral buffer, it decomposed rapidly to give theasinensin A as the major product. Theasinensin A suppressed the oxacillin resistance of methidllin-resistant Stphylcoccus aureus (MRSA). In the presence of theasinensin A (3.5 × 10-5 M), the minimum inhibitory concentrations (MICs) of oxacillin decreased from 256 or 64 μg/mL to 4 μg/mL for the MRSA strains used. The presence of this compound (3.5 × M-5) also decreased the MIC of other β-lactam (penicillin G, from 32 μg/ mL to 0.125-0.5 μg/mL; ampicillin, from 16-32 μg/ml to 0.5-1 μg/mL) and aminoglycoside (streptomycin, from 4- 16 μg/mL to 0.125 -4 μg/mL) antibiotics for the MRSA strains.

Original languageEnglish
Pages (from-to)984-989
Number of pages6
JournalPlanta Medica
Issue number11
Publication statusPublished - Nov 1 2003



  • Antibiotic resistance
  • Camellia sinensis
  • Epigallocatechin gallate
  • Gallic acid
  • MRSA
  • Polyphenol
  • Theaceae
  • Theasinensin A

ASJC Scopus subject areas

  • Analytical Chemistry
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Drug Discovery
  • Complementary and alternative medicine
  • Organic Chemistry

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