Bioconjugates of cyclodextrins of manganese salen-type ligand with superoxide dismutase activity

New conjugates of superoxide dismutase/catalase mimetics with cyclodestrins

“…In the present case, the improvement of SOD activity is better than that observed in other studies. On the basis of the data in the literature [31,32,52] and of the present results we can hypothesize that the cyclodextrin cavity could, in general, improve the catalytic activity for the presence, in proximity to the catalytic moiety, of an hydrophobic environment able to encapsulate radical species [53,54] and favour their reaction with the catalytic centre. In any case, the additional role in the catalytic mechanism of a side chain containing the amido group and of the OHs of CD could not be excluded.…”

“…4a and 4b are among the most efficient salen-based SOD mimetics. On the other hand the improvement of the SOD activity as a consequence of the conjugation of the cyclodextrin has been already observed in copper(II) complexes of functionalized cyclodextrins [31,32,51]. In the present case, the improvement of SOD activity is better than that observed in other studies.…”

“…K detector is the constant for the reaction between the O À 2 and the detector molecule and it is 2.6 Â 10 5 M À1 s À1 when the detector is cyt c and 5.88 Â 10 4 M À1 s À1 when the detector is NBT. The slope of the line, obtained by the best fit of the experimental data, allowed the calculation of the k cat value [32,48]. When cyt c was used as the detector molecule, the CD conjugates showed an atypical behaviour.…”

“…We have synthesized some SOD mimetics based on copper(II) complexes, conjugating b-cyclodextrin (CD) with amine ligands and have found that the cyclodextrin cavity improves, in some case greatly, the SOD activity of the complexes [30,31]. On the basis of the wide interest in salen derivatives, we have also synthesized a Mn(III) complex based on functionalized cyclodextrin, similar to the salen ligand [32]. This compound shows a good water solubility and a SOD activity similar to the EUK 8, but is not very stable in water.…”

The Supramolecular Attitude of Metal–Salophen and Metal–Salen Complexes

“…The N 2 O 2 coordination sphere reproduces the setting found for many metals in metalloproteins, since these ligands are structurally similar to porphyrins, but much easier to synthesize. Further, the possibility of incorporating two different benzylidene moieties and diamine backbones [3] provides access to a large variety of salen/salophen ligands that, after deprotonation of both phenolic oxygens, can form rather stable complexes with many transition and main group metals, with different oxidation states, coordination numbers and geometries that have shown interesting applications in many fields [4][5][6][7][8][9]. Recently also an extensive use of metal complexes with salen and salophen ligands has been reported in the design of new magnetic materials [10,11].…”