- Selenoureas and thioureas are effective superoxide radical scavengers in vitro
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Oxygen radicals, such as superoxide radicals, embellishing DNA, protein, lipids, etc., and carrying out the obstacle of the function of a cell is known. It depends for the oxidant level in the living body on the balance of a generation system and an elimination system of oxygen radicals, and research which controls an oxidant level in the living body is briskly done by taking in the substance which eliminates an oxygen radical. We investigated scavenging effects of superoxide radicals by selenoureas and thioureas using a highly sensitive and quantitative chemiluminescence method. At 330 nM, five selenoureas and five thioureas scavenged fractions of superoxide radicals (O 2-) ranging from 8.4% to 87.6%. Among five N,N-unsubstituted selenoureas and N,N-unsubstituted thioureas 1-selenocarbamoylpiperidine and 1-thiocarbamoylpyrrolidine were the most effective scavengers. A possibility that selenoureas could use it as a new superoxide anion-scavenging substance from the result of this research became clear.
- Takahashi, Hitoe,Nishina, Atsuyoshi,Fukumoto, Ryo-Hei,Kimura, Hirokazu,Koketsu, Mamoru,Ishihara, Hideharu
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p. 2185 - 2192
(2007/10/03)
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- Inhibition of tyrosinase activity by N,N-unsubstituted selenourea derivatives
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This study investigated inhibitory effects of N,N-unsubstituted selenourea derivatives on tyrosinase activity. Three types of N,N-unsubstituted selenoureas derivatives exhibited inhibitory effect on dopa (3,4-dihydroxyphenylalanine) oxidase activity of mushroom tyrosinase. Compound D at a concentration of 200/M exhibited 55.5% of inhibition on dopa oxidase activity of mushroom tyrosinase. This inhibitory effect was higher than that of kojic acid (39.4%), a well known tyrosinase inhibitor. Moreover, the compound D identified as a noncompetitive inhibitor by Lineweaver-Burk plot analysis. In addition, compound D also inhibited the melanin production in melan-a cells.
- Ha, Sang Keun,Koketsu, Mamoru,Lee, Kunho,Choi, Sang Yoon,Park, Ji-Ho,Ishihara, Hideharu,Kim, Sun Yeou
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p. 838 - 840
(2007/10/03)
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- A Simple Route to N,N-Disubstituted Selenoureas from N,N-Disubstituted Cyanamides
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N,N-Disubstituted selenoureas 4 can be obtained in satisfactory yields by addition of an acid to a mixture of freshly prepared sodium selenide and N,N-disubstituted cyanamides 5.
- Keil, Dietmar,Hartmann, Horst
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- Preparation of N,N-unsubstituted selenoureas and thioureas from cyanamides
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Reaction of cyanamides with LiAlHSeH and LiAlHSH in the presence of HCl in diethyl ether provided the corresponding N,N-unsubstituted selenoureas and thioureas in moderate to high yields, respectively.
- Koketsu, Mamoru,Fukuta, Yoshihisa,Ishihara, Hideharu
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p. 6333 - 6335
(2007/10/03)
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- Preparation and characterisation of N,N-disubstituted 2-amino-selenazoles
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As a result of checking suited methods for preparing N,N-disubstituted 2-amino-selenazoles 14 as a nearly unknown class of highly reactive selenazoles a simple route starting from N,N-disubstituted selenoureas 12 has been elaborated and used for the synthesis of a series of these compounds. The necessary selenium-containing starting compounds 12 are available from N,N-disubstituted cyanamides 18 and hydrogen selenide.
- Keil, Dietmar,Hartmann, Horst
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p. 169 - 184
(2007/10/03)
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