title: In vitro inhibitory effect of flavonoids on growth, infection and vacuolation of Helicobacter pylori.
abstract: Flavonoids, which are main constituents of herbal medicines, have been reported to inhibit the growth of Helicobacter pylori (HP). Therefore, to evaluate the anti-HP activity of some flavonoids (flavanols, flavones, flavonols and isoflavonoids), their effects on the growth and vacuolation of HP as well as the infective properties of HP against HeLa cells were investigated. Catechins, quercetin and naringenin weakly inhibited the growth of HP, but all tested compounds did not inhibit HP infection into KATO III cells and HP urease activity. Quercetin and naringenin inhibited HP VacA vacuolation in HeLa cells with IC (50) values of 0.046 and 0.36 mM, respectively. Quercetin also inhibited procaspase-3 activation to caspase-3 in HeLa cells induced by HP VacA toxin, which may induce cell death via the proteolytic activation of a cascade of caspases. However, quercetin did not affect Bax and Bcl-2 protein levels. Based on these findings, quercetin may improve gastric cell death by inhibiting apoptotic signaling by HP VacA toxin. Abbreviations. HP: Helicobacter pyloriBSA:bovine serum albumin ESL:enhanced chemiluminescence MIC:minimum inhibitory concentration MTT:methylthiazolyldiphenyl-tetrazolium bromide PBS:phosphate-buffered saline VacA:Vacuolating cytotoxin.
authors.affiliation: College of Pharmacy, Kyung Hee University, 1 Hoegi, Dongdaemun-ku, Seoul 130-701, Korea.
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Shin
authors.forename: Jong-Mi
authors.initials: JM
authors.lastname: Kim
authors.forename: Eun-Ah
authors.initials: EA
authors.lastname: Bae
authors.forename: Yang-Jin
authors.initials: YJ
authors.lastname: Hyun
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000378:metabolism; D001427:Bacterial Toxins / Q000378:metabolism; D005419:Flavonoids / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D006367:HeLa Cells / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000254:growth & development / Q000472:pathogenicity; D006801:Humans; D020128:Inhibitory Concentration 50; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D010946:Plants, Medicinal; D014617:Vacuoles / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D005419:Flavonoids; D010936:Plant Extracts; C074689:VacA protein, Helicobacter pylori