title: Theasinensin A, a tea polyphenol formed from (-)-epigallocatechin gallate, suppresses antibiotic resistance of methicillin-resistant Staphylococcus aureus.
abstract: 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 methicillin-resistant Staphylococcus aureus (MRSA). In the presence of theasinensin A (3.5 x 10(-5) M), the minimum inhibitory concentrations (MICs) of oxacillin decreased from 256 or 64 microg/mL to 4 microg/mL for the MRSA strains used. The presence of this compound (3.5 x 10(-5) M) also decreased the MIC of other beta-lactam (penicillin G, from 32 microg/mL to 0.125-0.5 microg/mL; ampicillin, from 16-32 microg/mL to 0.5-1 microg/mL) and aminoglycoside (streptomycin, from 4 - 16 microg/mL to 0.125-4 microg/mL) antibiotics for the MRSA strains.
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama, Japan. hatano@pharm.okayama-u.ac.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hatano
authors.forename: Miwako
authors.initials: M
authors.lastname: Kusuda
authors.forename: Mami
authors.initials: M
authors.lastname: Hori
authors.forename: Sumiko
authors.initials: S
authors.lastname: Shiota
authors.forename: Tomofusa
authors.initials: T
authors.lastname: Tsuchiya
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshida
mesh_terms: D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D001578:Benzopyrans / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry; D006801:Humans; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D010636:Phenols / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D013211:Staphylococcus aureus / Q000187:drug effects*; D013662:Tea
chemical_list: D000890:Anti-Infective Agents; D001578:Benzopyrans; D010636:Phenols; D010936:Plant Extracts; D013662:Tea; C481298:theasinensin A; D002392:Catechin; C045651:epigallocatechin gallate