title: Antioxidant activity of isocoumarins isolated from Paepalanthus bromelioides on mitochondria.
abstract: The isocoumarins (1-50 microM) paepalantine (9,10-dihydroxy-5,7-dimethoxy-1H-naptho(2,3c)pyran-1-one), 8,8'-paepalantine dimer, and vioxanthin isolated from Paepalanthus bromelioides, were assessed for antioxidant activity using isolated rat liver mitochondria and non-mitochondrial systems, and compared with the flavonoid quercetin. The paepalantine and paepalantine dimers, but not vioxanthin, were effective at scavenging both 1,1-diphenyl-2-picrylhydrazyl (DPPH(*)) and superoxide (O(2)(-)) radicals in non-mitochondrial systems, and protected mitochondria from tert-butylhydroperoxide-induced H(2)O(2) accumulation and Fe(2+)-citrate-mediated mitochondrial membrane lipid peroxidation, with almost the same potency as quercetin. These results point towards paepalantine, followed by paepalantine dimer, as being a powerful agent affording protection, apparently via O(2)(-) scavenging, from oxidative stress conditions imposed on mitochondria, the main intracellular source and target of those reactive oxygen species. This strong antioxidant action of paepalantine was reproduced in HepG2 cells exposed to oxidative stress condition induced by H(2)O(2).
authors.affiliation: Instituto de Química de Araraquara, Universidade Estadual Paulista, Araraquara, SP, Brazil.
authors.forename: Karina F
authors.initials: KF
authors.lastname: Devienne
authors.forename: Anaísa F
authors.initials: AF
authors.lastname: Cálgaro-Helena
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Dorta
authors.forename: Ieda M R
authors.initials: IM
authors.lastname: Prado
authors.forename: Maria Stella G
authors.initials: MS
authors.lastname: Raddi
authors.forename: Wagner
authors.initials: W
authors.lastname: Vilegas
authors.forename: Sérgio A
authors.initials: SA
authors.lastname: Uyemura
authors.forename: Antonio C
authors.initials: AC
authors.lastname: Santos
authors.forename: Carlos
authors.initials: C
authors.lastname: Curti
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D045744:Cell Line, Tumor; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D039262:Eriocaulaceae / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D049934:Isocoumarins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D015394:Molecular Structure; D009284:Naphthols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D049934:Isocoumarins; D009284:Naphthols; D010936:Plant Extracts; D017382:Reactive Oxygen Species; C108025:paepalantine; C023333:vioxanthin; D006861:Hydrogen Peroxide