Effect of the Cymbopogon citratus, Maytenus ilicifolia and Baccharis genistelloides extracts against the stannous chloride oxidative damage in Escherichia coli

Stannous ion has been used in different sectors of human interest, such as in food industry and in health sciences. Much is known about stannous chlor ide (SnCl2) toxicity, although, there is no general agreement regarding its genotoxicity. Cymbopogon citratus, Maytenus ilicifolia and Baccharis genis telloides extracts have been used in popular medicine. We evaluated the inf luence of these crude extracts on the survival of the Escherichia coli wild type (AB 1157) strain submitted to SnCl2) treatment. Reactive oxygen speci es (ROS) can be generated by a Fenton like reaction induced by SnCl2. E. co li culture was treated simultaneously with SnC12 and a specific extract. Ou r results showed a reduction of the SnC12 effect on the survival of the cul tures in presence of the crude extracts. The extract of M. ilicifolia showe d the highest level of protection action against the SnC12 effect in compar ison with the other extracts. This protector effect could due to the redox properties of these crude extracts. The compounds in the crude extracts cou ld (i) chelate stannous ions, protecting them against the oxidation and avo iding the generation of ROS, (ii) be a scavenger of the ROS generated by th e SnC12 oxidation and/or (iii) have oxidant compounds that could oxidise th e stannous ions, abolishing or reducing the SnCl2 effect. (C) 2001 Elsevier Science B.V. All rights reserved.