ABSTRACT
In nuclear medicine, stannous, as stannous chloride (SnCl2) and stannous fluoride (SnF2), are used as reducing agents to obtain radiopharmaceuticals labeled with technetium-99m. In the literature, the SnCl2 action was studied and it seems to be mediated through free radicals (FR) production in a Fenton-like reaction. In this work it was evaluated: (i) the in vitro SnF2 effects in different concentrations using pBCKS plasmid deoxyribonucleid acid (DNA); (ii) the SnF, effects in different Escherichia coli (E.coli) cultures, proficient or deficient in DNA repair genes, treated simultaneously with FR scavengers; and (iii) the biological effects of Maytenus ilicifolia, Baccharis genistelloides and Cymbopogon citratus aqueous extracts on the SnCL2 action in E.coli culture. The SnF2 treatment induced plasmidd DNA damages (single and double DNA strand breaks), in a dose-dependent manner. Citotoxicity mediated by SNf2 was observed and the simultaneous tratment with FR scavengers has increased the cell survival, suggesting the participation of FR on the SnF2-deleterious effects. The vegetal extrracts prottected the E.coli cells agains the SnCl2 effects. The components of the extracts could be interacting with SnCl2 blocking its participation in the FR formation.