Journal of the Brazilian Chemical Society
versión impresa ISSN 0103-5053
COSTA, Cicero de O. et al. Oncocalyxone A: electrochemical, spectroscopic investigation and studies of its interaction with DNA, nucleobases and N-acetylcysteine. J. Braz. Chem. Soc. [online]. 2012, vol.23, n.6, pp. 1174-1185. ISSN 0103-5053. http://dx.doi.org/10.1590/S0103-50532012000600024.
The formation of paramagnetic species from oncocalyxone A in aprotic medium was confirmed by performing in situ electrochemical-electron spin resonance (E-ESR) experiments. The high delocalization of the radical generated at the first reduction potential is clearly evidenced by the hyperfine coupling of H-9 with the larger coupling constant, besides the couplings at the H-3 (close to quinone) and H-7 (far from the quinone nucleus) positions. In protic medium, together with pH dependence experiments, oncocalyxone A showed to be DNA-reactive through experiments with DNA sensors. Its reaction with N-acetylcysteine, with structural characterization of the addition products, proved its ability as Michael acceptor. Both aspects are important in terms of biological/pharmacological activities and indicate the present models as important tools in the screening of biologically active compounds.
Palabras llave : oncocalyxone A; spectroelectrochemical-electron spin resonance; DNA interaction; N-acetylcysteine; Michael acceptor.