title: Novel chromone and xanthone derivatives: Synthesis and ROS/RNS scavenging activities.
abstract: Chromones and xanthones are oxygen-containing heterocyclic compounds acknowledged by their antioxidant properties. In an effort to develop novel agents with improved activity, a series of compounds belonging to these chemical classes were prepared. Their syntheses involve the condensation of appropriate 2-methyl-4H-chromen-4-ones, obtained via Baker-Venkataraman rearrangement, with (E)-3-(3,4-dimethoxyphenyl)acrylaldehyde to provide the corresponding 2-[(1E,3E)-4-(3,4-dimethoxyphenyl)buta-1,3-dien-1-yl]-4H-chromen-4-ones. Subsequent electrocyclization and oxidation of these compounds led to the synthesis of 1-aryl-9H-xanthen-9-ones. After cleavage of the protecting groups, hydroxylated chromones and xanthones were assessed as scavenging agents against both reactive oxygen species (ROS) [superoxide radical (O2(•-)), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), singlet oxygen ((1)O2), and peroxyl radical (ROO(•))] and reactive nitrogen species (RNS) [nitric oxide ((•)NO) and peroxynitrite anion (ONOO(-))]. Generally, all the tested new hydroxylated chromones and xanthones exhibited scavenger effects dependent on the concentration, with IC50 values found in the micromolar range. Some of them were shown to have improved scavenging activity when compared with previously reported analogues, allowing the inference of preliminary conclusions on the structure-activity relationship.
authors.affiliation: UCIBIO-REQUIMTE, Applied Chemistry Laboratory, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
authors.forename: Carina
authors.initials: C
authors.lastname: Proença
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Hélio M T
authors.initials: HM
authors.lastname: Albuquerque
authors.affiliation: UCIBIO-REQUIMTE, Applied Chemistry Laboratory, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
authors.forename: Daniela
authors.initials: D
authors.lastname: Ribeiro
authors.affiliation: UCIBIO-REQUIMTE, Applied Chemistry Laboratory, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
authors.forename: Marisa
authors.initials: M
authors.lastname: Freitas
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal; School of Agriculture, Polytechnic Institute of Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal. Electronic address: clems@ipb.pt.
authors.forename: Clementina M M
authors.initials: CM
authors.lastname: Santos
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
authors.affiliation: UCIBIO-REQUIMTE, Applied Chemistry Laboratory, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal. Electronic address: egracas@ff.up.pt.
authors.forename: Eduarda
authors.initials: E
authors.lastname: Fernandes
mesh_terms: D002867:Chromones / Q000737:chemistry*; D026361:Reactive Nitrogen Species / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000737:chemistry*; D044004:Xanthones / Q000737:chemistry*
chemical_list: D002867:Chromones; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D044004:Xanthones
keywords: Antioxidant activity; Chromones; Reactive nitrogen species; Reactive oxygen species; Xanthones