Antimutagenicity of lignin in vitro

The inhibitory activity of lignin against nitrosoguanidine (MNNG)- and acridine orange (AO)- induced mutagenesis was examined using two microbial systems: green unicellular flagellate Euglena gracilis and Salmonella typhimurium TA100 and TA97. To verify the hypothesis that the above mentioned mutagens may generate some oxidant species and subsequently free radicals, or they may interact with lignin, two physico-chemical measurements were performed. Lignin at a tested concentration (100 micrograms/ml) decreases Euglena-bleaching activity of MNNG by 67.7% and AO by 99.7%. Percentage of MNNG-induced revertants of S. typhimurium was also decreased substantially by lignin. We conclude that our results indicate the possible mechanisms behind the antimutagenic/anticarcinogenic effects of lignin: namely, scavening of reactive oxygen species produced by MNNG and binding of AO itself.