Bracken (Pteridium aquilinum)-induced DNA adducts in mouse tissues are different from the adduct induced by the activated form of the bracken carcinogen ptaquiloside

Following treatment with bracken fern (Pteridium aquilinum) extract and bra cken spores a number of DNA adducts were detected by P-32-postlabeling. Thr ee of these adducts have been described previously (Povey et al., Br. J. Ca ncer (1996) 74, 1342-1348) and in this study, using a slightly different pr otocol, four new adducts, with higher chromatographic mobility, were detect ed at levels ranging from 50 to 230% of those previously described, When DN A was treated in vitro with activated ptaquiloside (APT) and analysed by bu tanol extraction or nuclease P1 treatment, only one adduct was detected by P-32-postlabeling, This adduct was not present in the DNA from mice treated with bracken fern or spores, suggesting either that bracken contains genot oxins other than ptaquiloside or that the metabolism of ptaquiloside produc es genotoxins not reflected by activated ptaquiloside. However, as the ATP- derived adduct has been detected previously in ileal DNA of bracken-fed cal ves, species-specific differences in the metabolism of bracken genotoxins m ay exist, thereby leading to differences in their biological outcomes. (C) 2001 Academic Press.