title: Stimulation of acidic reduction of nitrite to nitric oxide by soybean phenolics: possible relevance to gastrointestinal host defense.
abstract: This study aimed to evaluate the potential of soybean-promoted acidic nitrite reduction and to correlate this activity with the content of phenolics and with the bactericidal activity against Escherichia coli O157:H7. Extracts of embrionary axes and cotyledons enriched in phenolics increased •NO formation at acidic pH at values that were 7.1 and 4.5 times higher, respectively, when compared to the reduction of the nonenriched extracts. Among the various phenolics accumulated in the soybean extracts, five stimulated nitrite reduction in the following decreasing order of potency: epicatechin gallate, chlorogenic acid, caffeic acid, galic acid and p-coumaric acid. Extracts of embrionary axes presented higher contents of epicatechin gallate and caffeic acid, compared to that of cotyledons, indicating a positive correlation between activity of the extracts and content of phenolics with regard to nitrite reducing activity. Soybean extracts enriched in phenolics interacted synergistically with acidified nitrite to prevent E. coli O157:H7 growth. The results suggest that soybean phenolics may interfere with the metabolism of •NO in an acidic environment by accelerating the reduction of nitrite, with a potential antimicrobial effect in the stomach.
authors.affiliation: Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas , P.O. Box 6109, Campinas, SP, Brazil, CEP 13083-970.
authors.forename: Pablo Gomes
authors.initials: PG
authors.lastname: Ferreira
authors.forename: Maria Angélica Suedan Souza
authors.initials: MA
authors.lastname: Lima
authors.forename: Robert Alvin
authors.initials: RA
authors.lastname: Bernedo-Navarro
authors.forename: Rogério Arcuri
authors.initials: RA
authors.lastname: Conceição
authors.forename: Edlaine
authors.initials: E
authors.lastname: Linhares
authors.forename: Alexandra Christine Helena Frankland
authors.initials: AC
authors.lastname: Sawaya
authors.forename: Tomomasa
authors.initials: T
authors.lastname: Yano
authors.forename: Ione
authors.initials: I
authors.lastname: Salgado
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002109:Caffeic Acids; D002392:Catechin / Q000031:analogs & derivatives; D019453:Escherichia coli O157 / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D009569:Nitric Oxide / Q000737:chemistry*; D009573:Nitrites / Q000737:chemistry*; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry* / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D012639:Seeds / Q000737:chemistry; D013025:Glycine max / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D002109:Caffeic Acids; D009573:Nitrites; D010636:Phenols; D010936:Plant Extracts; D009569:Nitric Oxide; D002392:Catechin; C062669:epicatechin gallate; C040048:caffeic acid