title: Effect of cobalt ion on radical intensity and cytotoxic activity of antioxidants.
abstract: The effect of CoCl2 on the cytotoxic activity of various antioxidants against human oral tumor cell lines (HSC-2, HSG) and normal human gingival fibroblasts (HGF) was investigated. Noncytotoxic concentrations of CoCl2 significantly reduced the cytotoxic activity of sodium ascorbate, gallic acid, epigallocatechin gallate (EGCG), curcumin and dopamine, but not that of sodium 5,6-benzylidene-L-ascorbate (SBA) and benzaldehyde. Among these compounds, benzaldehyde showed the most prominent tumor-specific cytotoxic action. ESR spectroscopy showed that these antioxidants produced radicals under alkaline condition and that their radical intensity was transiently enhanced and finally disappeared by addition of CoCl2. Antioxidants which are sensitive to CoCl2 generally had higher cytotoxic activity and oxidation potential (measured by NO monitor) and addition of CoCl2 significantly reduced their oxidation potential. The present study suggests that cobalt ion stimulates the oxidation of antioxidants to their inactive products.
authors.affiliation: Department of Biochemistry, School of Medicine, Showa University, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Sakagami
authors.forename: K
authors.initials: K
authors.lastname: Satoh
authors.forename: M
authors.initials: M
authors.lastname: Ishihara
authors.forename: H
authors.initials: H
authors.lastname: Sakagami
authors.forename: F
authors.initials: F
authors.lastname: Takeda
authors.forename: M
authors.initials: M
authors.lastname: Kochi
authors.forename: M
authors.initials: M
authors.lastname: Takeda
mesh_terms: D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001547:Benzaldehydes / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001597:Benzylidene Compounds / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D002392:Catechin / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D002414:Cations, Monovalent; D002460:Cell Line; D002648:Child; D003035:Cobalt / Q000378:metabolism / Q000494:pharmacology*; D003474:Curcumin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D004298:Dopamine / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D016166:Free Radical Scavengers / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D005707:Gallic Acid / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D009062:Mouth Neoplasms; D010084:Oxidation-Reduction; D014407:Tumor Cells, Cultured
chemical_list: D000975:Antioxidants; D001547:Benzaldehydes; D001597:Benzylidene Compounds; D002414:Cations, Monovalent; D016166:Free Radical Scavengers; D003035:Cobalt; D005707:Gallic Acid; D002392:Catechin; C045651:epigallocatechin gallate; C018021:cobaltous chloride; D003474:Curcumin; D001205:Ascorbic Acid; C070680:zilascorb; C032175:benzaldehyde; D004298:Dopamine