Study binding of Al–curcumin complex to ds-DNA, monitoring by multispectroscopic and voltammetric techniques

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 79; no. 5; pp. 1466 - 1474
• Main Authors: Ahmadi, F., Alizadeh, A.A., Shahabadi, N., Rahimi-Nasrabadi, M.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 01-09-2011
• Subjects: Aluminum - chemistry; Aluminum - metabolism; Al–curcumin complex; Animals; Binding Sites; Cattle; Circular Dichroism; Curcumin - analysis; Curcumin - chemistry; Curcumin - metabolism; DNA - analysis; DNA - chemistry; DNA - metabolism; In vitro DNA interaction; Magnetic Resonance Spectroscopy; Minor groove binding; Molecular Structure; Spectrometry, Fluorescence; Spectrophotometry, Infrared; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Minor groove binding; In vitro DNA interaction; Al–curcumin complex; Circular dichroism
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2011.05.002

The study of interaction of Al–curcumin complex with ds-DNA, by multispectroscopic and voltammetric techniques.
[Display omitted]
► In Alzheimer's disease (AD) the Al
3+ ions accumulated within the brain and interact with DNA. ► The results revealed the curcumine reduced the bonding affinity of Al
3+ to DNA. ► A binding model of DNA-Al-curcumin has been developed by using a multispectroscopic and voltammetric techniques. ► The CD results showed that only the Δ-ACC interacts with DNA. ► The cyclic voltammetry showed that ACC interact with DNA with a bonding site size of 2. The Δ-ACC interacts with DNA via partial electrostatic and minor groove binding.
In this work a complex of Al
3+ with curcumin ([Al(curcumin) (EtOH)
2](NO
3)
2) was synthesized and characterized by UV–vis, FT-IR, elemental analysis and spectrophotometric titration techniques. The mole ratio plot revealed a 1:1 complex between Al
3+ and curcumin in solution. For binding studies of this complex to calf thymus-DNA various methods such as: UV–vis, fluorescence, circular dichroism (CD), FT-IR spectroscopy and cyclic voltammetry were used. The intrinsic binding constant of ACC with DNA at 25
°C was calculated by UV–vis and cyclic voltammetry as 2.1
×
10
4 and 2.6
×
10
4, respectively. The thermodynamic studies showed that the reaction is enthalpy and entropy favored. The CD results showed that only the Δ-ACC interacts with DNA and the Δ-ACC form has not any tendency to interact with DNA, also the pure curcumin has not any stereoselective interaction with CT-DNA. Fluorimetric studies showed that fluorescence enhancement was initiated by a static process in the ground state. The cyclic voltammetry showed that ACC interact with DNA with a binding site size of 2. From the FT-IR we concluded that the Δ-ACC interacts with DNA via partial electrostatic and minor groove binding. In comparison with previous works it was concluded that curcumin significantly reduced the affinity of Al
3+ to the DNA.