title: Effect of antioxidants on radical intensity and cytotoxicity of hydroquinone.
abstract: Hydroquinone (HQ) dose-dependently reduced the viable cell number of oral tumor cell lines (HSC-2, HSG). HQ induced internucleosomal DNA fragmentation in human promyelocytic leukemic HL-60 cells, but not in HSC-2 nor HSG cells. Cytotoxic activity of HQ was slightly reduced by catalase, but was enhanced by superoxide dismutase, suggesting the possible involvement of hydrogen peroxide in HQ-induced cytotoxicity. This was supported by slight increase or decrease of cytotoxicity of HQ in the presence of Cu2+ and Fe3+, respectively. Lower concentrations of sodium ascorbate, ascorbic acid and ascorbic acid 6-palmitate reduced both the radical intensity and cytotoxic activity of HQ, more efficiently than ascorbic acid 2,6-dipalmitate, in contrast to the cytotoxic action of these ascorbates at higher (millimolar) concentrations. Popular antioxidants such as N-acetyl-L-cysteine and cysteine also reduced the radical intensity and cytotoxic activity of HQ. The present study suggests that cytotoxic activity of HQ is generated by radical-mediated oxidation mechanism.
authors.affiliation: Department of Oral Diagnosis, Meikai University School of Dentistry, Saitama, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Terasaka
authors.forename: F
authors.initials: F
authors.lastname: Takayama
authors.forename: K
authors.initials: K
authors.lastname: Satoh
authors.forename: S
authors.initials: S
authors.lastname: Fujisawa
authors.forename: H
authors.initials: H
authors.lastname: Sakagami
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology; D002374:Catalase / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D004249:DNA Damage; D004347:Drug Interactions; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000633:toxicity; D018922:HL-60 Cells / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006873:Hydroquinones / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000633:toxicity*; D009062:Mouth Neoplasms / Q000378:metabolism / Q000473:pathology; D009153:Mutagens / Q000378:metabolism / Q000633:toxicity*; D012468:Salivary Gland Neoplasms / Q000378:metabolism / Q000473:pathology; D013482:Superoxide Dismutase / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D006873:Hydroquinones; D009153:Mutagens; D002374:Catalase; D013482:Superoxide Dismutase; C031927:hydroquinone