Lignin component of plant biomass is highly branched non-toxic polymer composed of phenylpropane units, e.g., guaiacyl and syringyl with hydroxyl and carbonyl substitutions.The potential protective role of lignin preparations derived from wood pulping against carcinogenesis was examined by characterization of their antigenotoxic activity against DNA-based modification generated by hydrogen peroxide and N-methyl-N-nitro-N-nitrosoguanidine (MNNG) in in vitro experiments on hamster lung cells V79.It is known that in adition to alkyl lesion MNNG gives rise of hydroxyl free radicals, which may play a role in human gastric cancer.The level of oxidized DNA lesions was significantly lower in hamster cells preincubated with lignin before treatment with MNNG.The antioxidative effect of lignin against MNNG-induced oxidative DNA damage is comparable with that of the synthetic antioxidant butylated hydroxyanisole.The protective activity of lignin against DNA lesions induced by model genotoxins was examined on rat primary hepatocyte and testicular cells.In in vitro experiments, freshly isolated rat hepatocyte and testicular cells were preincubated with lignin before treatment with hydrogen peroxide and/or 1,2-dibromo-3-chloroproparte (DBCP).This halogenated aliphatic hydrocarbon pesticide induced DNA damage resulting in incidence of testicular cancer.The lignin preparations reduced the level of direct H2O2-induced DNA strand breaks in both type of cells due to their antioxidant nature.The observed protective effect of lignin against DBCP-induced DNA lesions may be explain by its ability to adsorb genotoxins of thus reducing its effective amount in the cells tested.