Eupafolin: Effect on mitochondrial energetic metabolism.
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.
Herrerias
Tatiana
T
Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, CP 19046, CEP 81531-990, Curitiba, Brazil.
de Oliveira
Brás H
BH
Gomes
Maria A B
MA
de Oliveira
Maria B M
MB
Carnieri
Eva G S
EG
Cadena
Sílvia M S C
SM
Martinez
Glaucia R
GR
Rocha
Maria E M
ME
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
D047309:Flavones; D018698:Glutamic Acid; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases; C503624:eupafolin