Resumen

GUERRA, Wendell et al. Three new complexes of platinum(II) with doxycycline, oxytetracycline and chlortetracycline and their antimicrobial activity. J. Braz. Chem. Soc. [online]. 2006, vol.17, n.8, pp. 1627-1633. ISSN 0103-5053.  http://dx.doi.org/10.1590/S0103-50532006000800021.

This paper reports on the synthesis and characterization of three new platinum(II) complexes with oxytetracycline, doxycycline and chlortetracycline by elemental analysis, IR and ¹⁹⁵Pt RMN spectroscopies. Doxycycline interactions with Pt^II ions as a function of the pH were studied by ¹H NMR. All the investigated tetracyclines form 1:1 complexes with Pt^II via the oxygen of the hydroxyl group and oxygen of the amide group at ring A. The minimal inhibitory concentrations (MIC) of the ligands and those of their Pt^II compounds were determined in two sensitive strains (E. coli HB 101 and E. coli ATCC 25922) and in a resistant one (E. coli HB101/pBR322). Platinum complex of doxycycline is twice as potent as the free antibiotic in the resistant strain. Octanol/water partition coefficients of the complexes were determined. Increasing lipophilicity enhances antimicrobial activity in the resistant strain.

Palabras llave : tetracycline derivatives; platinum complexes; antimicrobial activity; bacterial resistance.