Effect of cystathionine as a scavenger of superoxide generated from human leukocytes or derived from xanthine oxidase in vitro.
We studied the direct effects of cystathionine on human leukocyte-generated or xanthine-xanthine oxidase-derived superoxide radicals in vitro. Washed leukocyte suspensions (10(6) cells/ml) prepared from healthy male volunteers were stimulated with phorbol myristate acetate (1 mu M) or opsonized zymosan (1 mg/ml) to generate superoxide radicals, which were measured with a 2-methyl-6-[p-methoxyphenyl]-3,7-dihydroimidazo[1,2-alpha] pyrazin-3-one hydrochloride (MCLA)-chemiluminescence method. Cystathionine (30 mu M to 10 mM) significantly reduced superoxide radical-dependent chemiluminescence in the leukocyte system in a concentration-dependent manner. In addition, in the two different methods of determination of superoxide radicals (MCLA chemiluminescence and nitroblue tetrazolium reduction), cystathionine significantly scavenged the superoxide radicals derived from the xanthine-xanthine oxidase system. However, cystathionine did not inhibit the activity of xanthine oxidase during superoxide generation. On the other hand, cystathionine did not show a scavenging effect against hydroxyl radicals derived from Fe2+ -H2O2 on the erythrocyte membrane. These results indicate that cystathionine itself may possess a scavenging function against superoxide radicals rather than against hydroxyl radicals in vitro.
Department of Clinical Pharmacology, Faculty of Medicine, Tottori University, Yonago, Japan.
K
K
Wada
Y
Y
Kamisaki
K
K
Nakamoto
T
T
Itoh
D003540:Cystathionine / Q000494:pharmacology*; D004910:Erythrocyte Membrane / Q000378:metabolism; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006801:Humans; D017665:Hydroxyl Radical; D007093:Imidazoles / Q000378:metabolism; D007962:Leukocytes / Q000378:metabolism*; D015227:Lipid Peroxidation; D011719:Pyrazines / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D014969:Xanthine Oxidase / Q000378:metabolism*
D016166:Free Radical Scavengers; D007093:Imidazoles; D011719:Pyrazines; D013481:Superoxides; C063412:2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyrazin-3-one; D017665:Hydroxyl Radical; D003540:Cystathionine; D014969:Xanthine Oxidase