On the role of hydroxyl radical and the effect of tetrandrine on nuclear factor--kappaB activation by phorbol 12-myristate 13-acetate.
Nuclear factor kappaB (NF-kappaB) is considered to be an important target for therapeutic intervention because of its role in the regulation of proinflammatory and profibrotic mediators. The present study examined the role of hydroxyl (*OH) radical and the effect of tetrandrine, an alkaloid extracted from the Chinese medicinal herb Stephania tetrandra, on NF-kappaB activation by a tumor promoter, phorbol 12-myristate 13-acetate (PMA) in human lymphoid T cells (ie, Jurkat cells). Exogenous superoxide dismutase (SOD) enhanced the NF-kappaB activation by PMA, while catalase blocked it. Formate, a scavenger of *OH radical, also was inhibitory, as was deferoxamine, a metal chelator. These data suggest an important role of *OH radical in PMA-induced NF-kappaB activation. Incubation of the cells with tetrandrine prior to the stimulation of the cells was found to inhibit PMA-induced NF-kappaB activation. Tetrandrine activity was so potent that 50 microM of tetrandrine was sufficient to inhibit activation of NF-kappaB completely. Electron spin resonance (ESR) spin trapping was used to investigate the antioxidant action of tetrandrine using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap. Tetrandrine is an antioxidant for both *OH and superoxide (O2-)radicals. The reaction rate constant of tetrandrine with *OH is 1.4 x 10(10) M(-1)sec(-1), which is comparable with several well established antioxidants, such as ascorbate, glutathione, and cysteine. The Fenton reaction (Fe(II) + H2O2-->Fe(III) + *OH + OH-) and xanthine/xanthine oxidase were used as sources of *OH and O2- radicals. The free radical scavenging activity of tetrandrine is responsible for its inhibition of PMA-induced NF-kappaB activation.
Ye
J
J
Pathology and Physiology Research Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 25605, USA.
Ding
M
M
Zhang
X
X
Rojanasakul
Y
Y
Shi
X
X
D000470:Alkaloids / Q000494:pharmacology*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology; D044182:Benzylisoquinolines; D002273:Carcinogens / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D017665:Hydroxyl Radical / Q000378:metabolism*; D019169:Jurkat Cells / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology; D010766:Phosphorylation; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D019820:Xanthine / Q000494:pharmacology; D014969:Xanthine Oxidase / Q000494:pharmacology
D000470:Alkaloids; D000894:Anti-Inflammatory Agents, Non-Steroidal; D000975:Antioxidants; D044182:Benzylisoquinolines; D002273:Carcinogens; D004268:DNA-Binding Proteins; D016166:Free Radical Scavengers; D016328:NF-kappa B; D016877:Oxidants; D013481:Superoxides; D019820:Xanthine; C009438:tetrandrine; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D014969:Xanthine Oxidase; D013755:Tetradecanoylphorbol Acetate