Tannins from barks of Pinus caribaea protect Escherichia coli cells against DNA damage induced by γ-rays

This work was aimed to evaluate genotoxicity and antigenotoxicity activity against γ-rays of a tannin fraction obtained from barks of Pinus caribaea, as well as to elucidate the antigenotoxic mechanisms involved in radioprotection by using different approaches as pre-, co- and post-irradiation cell treatments with plant extract. The tannin fraction was not genotoxic to Escherichia coli cells in experiments using different exposure times. This extract was antigenotoxic against γ-rays when the cells were pre- or co-treated with this extracts, but not during post-irradiation treatments, suggesting a possibly antigenotoxic action through free radical scavenging mechanisms. The results are discussed in relation to the chemopreventive and therapeutic potential of the studied plant species. © 2005 Elsevier B.V. All rights reserved.