Interaction between quercetin–copper(II) complex and DNA with the use of the Neutral Red dye fluorophor probe

摘要: The interaction of quercetin-Cu(II) complex with calf thymus DNA was investigated the use Neutral Red (NR) dye as a spectral probe by application UV-vis spectrophotometry, cyclic voltammetry and synchronous fluorescence spectroscopy. results showed that both NR molecule can intercalate into double helix DNA. 2:1 quercetin:Cu(II) (estimated binding constant = 2.85 x 10(9)) is stabilized intercalation in (binding constant, K[quercetin-Cu(II)-DNA] (1.82 +/- 0.20) 10(5) M-1), displaces from NR-DNA competitive reaction. Cyclic studies confirm reaction show ratio (K-R/K-O) constants for reduced oxidized forms metal 2.05. Furthermore, alternative least squares (ALS) method applied to resolve two-way array absorption spectra data. This yielded equilibrium concentration profiles each component (NR, quercetin-Cu(II)) well corresponding pure spectra. extracted at [NR-DNA] [NR] trends decreased increased symmetrically, respectively, approximately linear behaviour being observed below 10 10(-6) mol L-1 added quercetin-Cu2+ complex. Thereafter, these converged asymptotically. free [quercetin-Cu(II)] trend-line over whole range added. It possible estimate approximate value exchange process (approximately 5 10(-1)) involving also found about 35% bound unaccounted reaction, presumably an site. (c) 2006 Elsevier B.V. All rights reserved.