Tolyporphin Macrocycles from the Cyanobacterium Tolypothrix nodosa Selectively Bind Copper and Silver and Reverse Multidrug Resistance

作者：Prinsep Michele R^*; Appleton Trevor G; Hanson Graeme R; Lane Ian; Smith Charles D; Puddick Jonathan; Fairlie David P

来源：Inorganic Chemistry, 2017, 56(10): 5577-5585.

DOI：10.1021/acs.inorgchem.6b03000

Tolyporphins are glycosylated macrocycles isolated from lipophilic soil extracts of the cyanobacterium, Tolypothrix nodosa, and found to potentiate the cytotoxicity of antitumor drugs like vinblastine and adriomycin. Here we find that, unlike porphyrins, tolyporphins are not able to form complexes with most metal ions. However, they do react strongly with copper(II). and silver(II), forming square-planar Metal complexes with an unpaired electron in a d(x)(-y)(2)(2) orbital of the Metal delocalized onto the Noting tolyporphin nitrogen atoms. Complexes were characterized by visible absorption spectra, mass spectrometry (EI, FAB, ESI, LDI-TOF, and MATADI-TOF) and multifrequency continuous-wave electron paramagnetic resonance spectra. Copper(II) and silver(II) complexes of tolyporphins A and E were found to have the interesting property of reversing multidrug resistance (MDR), with the copper complexes being less toxic than free tolyporphins. Reactive oxygen-free radicals were implicated-in both the cytotoxic and MDR-reversing effects of free and metalated tolyporphins.

• 出版日期2017-5-15