title: The catecholic antioxidant piceatannol is an effective nitrosation inhibitor via an unusual double bond nitration.
abstract: Piceatannol (1) was found to be more effective than caffeic acid, an established antinitrosating agent, in inhibiting N-nitrosation of 2,3-diaminonaphthalene. Product analysis of the reaction mixture of 1 (20 microM) with nitrite ions (80 microM) at pH 3.0 and at 37 degrees C showed conversion to a single major nitration product, (E)-3,3',4,5'-tetrahydroxy-beta-nitrostilbene (2) (68% yield). This would result from an unexpected nitration at the double bond sector via the 4-phenoxyl radical, which was analyzed at the unrestricted DFT level.
authors.affiliation: Department of Organic Chemistry and Biochemistry, University of Naples Federico II, Via Cintia, I-80126 Naples, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: De Lucia
authors.forename: Lucia
authors.initials: L
authors.lastname: Panzella
authors.forename: Orlando
authors.initials: O
authors.lastname: Crescenzi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Napolitano
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barone
authors.forename: Marco
authors.initials: M
authors.lastname: d'Ischia
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002109:Caffeic Acids / Q000494:pharmacology; D002396:Catechols / Q000494:pharmacology*; D007477:Ions; D008968:Molecular Conformation; D009281:Naphthalenes / Q000037:antagonists & inhibitors / Q000378:metabolism; D009566:Nitrates / Q000737:chemistry / Q000378:metabolism; D009573:Nitrites / Q000737:chemistry / Q000378:metabolism; D015538:Nitrosation / Q000187:drug effects*; D010636:Phenols / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D010938:Plant Oils / Q000737:chemistry; D013267:Stilbenes / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D002109:Caffeic Acids; D002396:Catechols; D007477:Ions; D009281:Naphthalenes; D009566:Nitrates; D009573:Nitrites; D010636:Phenols; D010938:Plant Oils; D013267:Stilbenes; C042329:phenoxy radical; C041525:3,3',4,5'-tetrahydroxystilbene; C040048:caffeic acid