Enhancement of antibacterial effects of epigallocatechin gallate, using ascorbic acid

Tsutomu Hatano, Mayumi Tsugawa, Miwako Kusuda, Shoko Taniguchi, Takashi Yoshida, Sumiko Shiota, Tomofusa Tsuchiya

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32 Citations (Scopus)


Although plant polyphenols such as (-)-epigallocatechin gallate (EGCG) have antibacterial activity towards methicillin-resistant Staphylococcus aureus (MRSA), such polyphenols are unstable in solution. Because the instability of polyphenols is attributable to their oxidation, we examined the effects of antioxidants and inhibitors of polyphenol oxidation on the maintenance of polyphenol antibacterial activity. The antibacterial activity of EGCG was enhanced in the presence of ascorbic acid, and ascorbic acid was the most effective for retaining the concentration of stable EGCG. On the other hand, the antibacterial activity of EGCG was lowered in the presence of casein in spite of its suppressing effect on the EGCG decrease. The effect of EGCG on the antibiotic resistance of MRSA was also enhanced in the presence of ascorbic acid. The addition of an antioxidant may affect other pharmacological effects of polyphenols in analogous ways, although this does not mean the clinical usefulness of the addition directly.

Original languageEnglish
Pages (from-to)3111-3116
Number of pages6
Issue number18
Publication statusPublished - Dec 2008



  • Antibacterial
  • Antibiotic resistance
  • Ascorbic acid
  • Camellia sinensis L. (Theaceae)
  • Epigallocatechin gallate
  • Methicillin-resistant Staphylococcus aureus
  • Polyphenol
  • Tea

ASJC Scopus subject areas

  • Plant Science
  • Biochemistry
  • Molecular Biology
  • Horticulture

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