title: Ascorbic acid potentiates the cytotoxicity of the naphthoquinone 5-methoxy-3,4-dehydroxanthomegnin.
abstract: The interaction of ascorbic acid with 5-methoxy-3,4-dehydroxanthomegnin, an 1,4-naphthoquinone, was investigated using the cytotoxic index for McCoy cells by neutral red assay. The synergistic effect was observed when such compounds were added simultaneously, most probably due to hydrogen peroxide being generated by ascorbate-driven 5-methoxy-3,4-dehydroxanthomegnin redox cycling. Incubation of cells in the presence of 5-methoxy-3,4-dehydroxanthomegnin/ascorbic acid/catalase, an enzyme that destroys H2O2, resulted in an increase of cell survival, reinforcing the involvement of hydrogen peroxide generated as an important oxidizing agent that kills McCoy cells.
authors.affiliation: Universidade Estadual Paulista-UNESP, Instituto de Química, Rua Prof. Francisco Degni, s/n, CEP 14801-970, Araraquara, SP, Brazil.
authors.forename: Rodrigo R
authors.initials: RR
authors.lastname: Kitagawa
authors.forename: Luiz M
authors.initials: LM
authors.lastname: da Fonseca
authors.forename: Valdecir F
authors.initials: VF
authors.lastname: Ximenes
authors.forename: Najeh M
authors.initials: NM
authors.lastname: Khalil
authors.forename: Wagner
authors.initials: W
authors.lastname: Vilegas
authors.forename: Maria Stella G
authors.initials: MS
authors.lastname: Raddi
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000737:chemistry*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D051379:Mice; D015394:Molecular Structure; D009285:Naphthoquinones / Q000737:chemistry* / Q000633:toxicity*
chemical_list: C531413:5-methoxy-3,4-dehydroxanthomegnin; D009285:Naphthoquinones; D001205:Ascorbic Acid