title: Eupafolin: Effect on mitochondrial energetic metabolism.
abstract: This study evaluated the effects of flavone eupafolin (6-methoxy 5,7,3',4'-tetrahydroxyflavone), extracted from dry leaves of Eupatorium litoralle. Eupafolin (25-200microM) promoted inhibition of the respiratory rate in state 3, in the presence of glutamate or succinate. During succinate oxidation, it was found that only state 4 respiratory rate was stimulated approximately 30% by eupafolin (100microM) and ADP/O ratio and RCC were reduced with all doses. When glutamate was used as substrate, RCC was similarly reduced. Eupafolin caused a reduction of enzymatic activities between complexes I and III of the respiratory chain. Cytochrome c oxidase and ATPase activities were not affected. Using voltammetry cyclic analysis, eupafolin give rise to irreversible oxidation with an anodic peak potential at +0.08V (SHE). We also observed that eupafolin can undergo oxidation catalyzed by EDTA-Fe, promoting cytochrome c reduction in the presence of NADH, resulting in the production of the superoxide radical and hydrogen peroxide. All together, the results could explain the cytotoxic effects observed previously with the eupafolin.
authors.affiliation: Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, CP 19046, CEP 81531-990, Curitiba, Brazil.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Herrerias
authors.forename: Brás H
authors.initials: BH
authors.lastname: de Oliveira
authors.forename: Maria A B
authors.initials: MA
authors.lastname: Gomes
authors.forename: Maria B M
authors.initials: MB
authors.lastname: de Oliveira
authors.forename: Eva G S
authors.initials: EG
authors.lastname: Carnieri
authors.forename: Sílvia M S C
authors.initials: SM
authors.lastname: Cadena
authors.forename: Glaucia R
authors.initials: GR
authors.lastname: Martinez
authors.forename: Maria E M
authors.initials: ME
authors.lastname: Rocha
mesh_terms: D000251:Adenosine Triphosphatases / Q000187:drug effects; D019069:Cell Respiration / Q000187:drug effects*; D003576:Electron Transport Complex IV / Q000187:drug effects; D047309:Flavones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D018698:Glutamic Acid / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013329:Structure-Activity Relationship
chemical_list: D047309:Flavones; D018698:Glutamic Acid; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases; C503624:eupafolin