Radioprotective effects of thiomethylhydantoin derivatives on Escherichia coli and mice.
Protection of Escherichia coli NIHJ and C57BL mice from the effects of 60Co gamma-rays provided by S-alk(en)yl-L-cysteines and their hydantoin derivatives was examined. E. coli (10(6) cells/ml) suspended in a 20 mM aqueous solution of one of the drugs was irradiated with 60 Gy of gamma-rays. Five week-old male mice were exposed to 5.0-9.5 Gy of gamma-rays after a single intraperitoneal injection of 0.75 mmol/kg body weight of each compound. In both E. coli and mice, S-allyl compounds afforded more effective radioprotection than S-propyl compounds. The replacement of the alpha-hydrogen of S-substituted cysteines by methyl groups decreased the radioprotective effect. Hydantoin derivatives were much more radioprotective than the original sulfur-containing amino acids. Especially, DL-5-allylthiomethyl-5-methylhydantoin had a remarkable radioprotective effect in mice. The gamma-radiolysis mechanism of thiomethylhydantoin derivatives was discussed in connection with the radioprotective effect of the drugs.
Nishimura
A
A
Department of Radiological Technology, Kawasaki College of Allied Health Professions, Kurashiki, Japan.
Aono
K
K
D000818:Animals; D003037:Cobalt Radioisotopes; D003545:Cysteine / Q000031:analogs & derivatives*; D004926:Escherichia coli / Q000528:radiation effects*; D006827:Hydantoins / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011837:Radiation-Protective Agents / Q000378:metabolism / Q000494:pharmacology*; D013867:Thiohydantoins / Q000378:metabolism / Q000494:pharmacology*
D003037:Cobalt Radioisotopes; D006827:Hydantoins; D011837:Radiation-Protective Agents; D013867:Thiohydantoins; D003545:Cysteine