title: Epigallocatechin gallate and gallocatechin gallate in green tea catechins inhibit extracellular release of Vero toxin from enterohemorrhagic Escherichia coli O157:H7.
abstract: We studied the effects of six catechin derivatives (catechin, epigallocatechin, epicatechin, epicatechin gallate, epigallocatechin gallate (EGCg) and gallocatechin gallate (GCg)) in green tea on the production and extracellular release of Vero toxins (VTs) from enterohemorrhagic Escherichia coli (EHEC) cultured at 37 degrees C for 24 h. EGCg and GCg in the culture medium markedly inhibited extracellular VTs release from EHEC cells into the culture supernatant fluid at concentrations of 0.05 mg/ml or higher, as estimated by both the reversed passive latex agglutination assay and cytotoxic assay using Vero cells. Production and extracellular release of maltose binding protein, a periplasmic protein, into the culture supernatant were also inhibited by EGCg and GCg, indicating that their inhibitory effect on release from periplasm into the outer milieu is not specific to VTs, but general to the proteins accumulated in EHEC periplasm.
authors.affiliation: Department of Biomedical Food Research, National Institute of Infectious Diseases, Toyama, Tokyo, Japan. ykonishi@nih.go.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Sugita-Konishi
authors.forename: Y
authors.initials: Y
authors.lastname: Hara-Kudo
authors.forename: F
authors.initials: F
authors.lastname: Amano
authors.forename: T
authors.initials: T
authors.lastname: Okubo
authors.forename: N
authors.initials: N
authors.lastname: Aoi
authors.forename: M
authors.initials: M
authors.lastname: Iwaki
authors.forename: S
authors.initials: S
authors.lastname: Kumagai
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001427:Bacterial Toxins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000494:pharmacology; D002457:Cell Extracts; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology*; D019897:Periplasm / Q000378:metabolism; D022622:Shiga Toxin 1; D013662:Tea / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D002457:Cell Extracts; D005419:Flavonoids; D022622:Shiga Toxin 1; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate; C057580:gallocatechol