Enhancement of antibacterial effects of epigallocatechin gallate, using ascorbic acid.
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.
Hatano
Tsutomu
T
Department of Pharmacognosy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Tsushima, Okayama 700-8530, Japan. hatano@pharm.okayama-u.ac.jp
Tsugawa
Mayumi
M
Kusuda
Miwako
M
Taniguchi
Shoko
S
Yoshida
Takashi
T
Shiota
Sumiko
S
Tsuchiya
Tomofusa
T
D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013997:Time Factors
D000900:Anti-Bacterial Agents; D002392:Catechin; C045651:epigallocatechin gallate; D001205:Ascorbic Acid