Oxidative/antioxidative effects of different lignin preparations on DNA inhamster V79 cells

Endogenous oxidative damage to DNA is thought to be an important etiologic factor in the development of chronic diseases such as cancer. Many products of the vegetable kingdom have been suggested to limit oxidative damage to DNA in humans. To this group belong lignins, polyphenols present in all pla nts (including edible plants). The aim of this study was to examine oxidati ve/antioxidative effects of different lignin preparations on mammalian DNA. In addition to a water-soluble sulfur-free lignin 1 which was obtained by fractionation of hardwood hydrolysate, we investigated lignin 2 (obtained b y oxidation of lignin 1), lignin 3 (prepared by the extraction of lignin 2 with a mixture ethanol-water 3:1), lignin 4 (Na-salt of lignin 3) and ligni n 5 (prepared by extraction of lignin 2 with diethylether). Our results sho wed that only the original lignin 1 did not increase substantially the leve l of DNA damage. Lignins 2, 3,4 and 5 increased both the level of frank DNA strand breaks + alkali-labile sites and the level of FPG-sensitive sites r epresenting oxidative damage to DNA. Lignin I was further tested for its an tioxidative activity against DNA base modifications generated by visible li ght+photosensitizer. Obtained results confirmed the oxygen species-scavengi ng activity of lignin 1.