Antimutagenic activity of vitamin B1 against damages induced by chemical and physical mutagens in Salmonella typhimurium and Escherichia coli

Thiamine (vitamin B1) is an essential nutrient acting mainly as an enzymatic cofactor on diverse cell processes. It has been reported that vitamin B1 has a significant role in the signaling pathways related to the response to adverse environmental conditions (chemical and physical). The objectives of this study were to evaluate the antimutagenic potential of vitamin B1 in front of DNA-alkylating agents in the presence/absence of ogt and ada repairing genes in Salmonella typhimurium strains and against damage induced by ultraviolet light type C in Escherichia coli strains mutated at the uvrABC system and recBCD enzymes. For S. typhimurium, an antimutagenesis test (Ames test) was performed using strains deficient in one or both genes (YG7100 ada^-/ogt⁺, YG7104 ada⁺/ogt^-, YG7108 ada^-/ogt^-). For E. coli, mutated strains (K-12 derived strains Hfr H180 uvrB⁺/recA⁺, W3110 uvrB⁺/recA^- and ATCC®8739 uvrB^-/recA⁺) were exposed to UV-C light at different time intervals, with and without vitamin B1. Our results showed that thiamine is an antimutagen against methyl-N-nitro-N-nitrosoguanidine or ethyl-N-nitro-N-nitrosoguanidine only when the ogt gene is present. While for E. coli, the presence of vitamin B1 increased the survival rate, implying an antimutagenesis independent of uvrABC repairing system and recBCD enzymes.