The interaction of calf thymus DNAwith [CuL(ClO4)]ClO4·H2O (1) and [ZnLBr]Br·H2O (2) (L =9,12,15,18,27,28-hexaaza-29-oxatetracyclo[24.2.1.02,7.020,25]enneicosa-2,4,6,20,22,24,26,281-octaene)dicationic complexes in aqueous solution at neutral pH, was investigated by variable-temperature UV-visabsorption, circular dichroism and fluorescence spectroscopy. The values of the DNA-binding constantsof these complexes, determined by competitive binding spectrofluorimetric titrations of ethidium bromide(EB)–DNA solutions, are (6.7 ± 0.5) × 106 M−1 for CuL2+ and (4.7 ± 0.5) × 105 M−1 for ZnL2+. Thesedata together with a through analysis of the spectroscopic behaviour consistently suggest that bothcompounds are effective DNA binders. Interestingly, the DNA-binding strength of these complexes hasbeen found to be correlated to their in vitro cytotoxic activity toward human breast carcinoma cells,although the complex with lower DNA-binding affinity is more active. In fact, biological studies showedthat when the compounds are delivered through the cell membrane by a lipidic carrier, the cell survival issensibly reduced, up to 58% with 1 and to 31% with 2.
|Numero di pagine||7|
|Stato di pubblicazione||Published - 2012|
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