Thiamine Is a Precursor of DNA Strand Breakage and Mutagenic Substance (s) When Mixed with Nitrite

Abstract

DNA strand breakage activity and mutagenicity of the product (s) formed by a reaction of thiamine and nitrite under simulated gastric conditions were examined. A reaction mixture of thiamine and nitrite at pH 3 induced DNA single-strand breaks when incubated with a supercoiled Plasmid DNA at pH 7.4 and 37°C. Product (s) from thiamine and nitrite were found mutagenic to Salmonella typhimurium TA100 strain without metabolic activation. The number of His+ revertant colonies was 1200/10-µmol eq of thiamine. Hence, thiamine is an undesirable precursor of DNA strand breakage and mutagenic substance (s) when mixed with nitrite. © 1995, The Pharmaceutical Society of Japan. All rights reserved.