Analysis of Binding Interaction of Curcumin and Diacetylcurcumin with Human and Bovine Serum Albumin Using Fluorescence and Circular Dichroism Spectroscopy

Abstract

The current study reports the binding of curcumin (CUR) as the main pharmacologically active ingredient of turmeric and diacetylcurcumin (DAC) as a bioactive derivative of curcumin to human serum albumin (HSA) and bovine serum albumin (BSA). The apparent binding constants and number of substantive binding sites have been evaluated by fluorescence quenching method. The distance (r) between donor (HSA and BSA) and acceptor (CUR and DAC) was obtained on the basis of the Förster's theory of non-radiative energy transfer. The minor changes on the far-UV circular dichroism spectra resulted in partial changes in the calculated secondary structure contents of HSA and BSA. The negligible alteration in the secondary structure of both albumin proteins indicated that ligand-induced conformational changes are localized to the binding site and do not involve considerable changes in protein folding. The visible CD spectra indicated that the optical activity observed during the ligand binding due to induced-protein chirality. All of the achieved results suggested the important role of the phenolic OH group of CUR in the binding process.

Characterization of resveratrol–milk protein interaction

“…2B, the CD spectra of native BSA showed two negative bands in the ultraviolet region at around 209 and 221 nm which is a characteristic of an a-helical structure protein and consistent with those previously reported (Shaikh et al, 2007;Mohammadi et al, 2009;Sun et al, 2005). When RES was added to the protein solution, the CD spectra was similar to the native protein in shape, which indicates the structure of BSA after resveratrol binding to BSA is also predominantly a-helical with no major changes in secondary structure of the protein (Hu et al, 2005;Shaikh et al, 2007).…”

“…Circular dichroism (CD) is one of the strongest and more sensitive spectroscopic techniques to explore the various aspects of protein structure, folding and binding properties of proteins and also their interaction with small molecules, as it can reveal very small alterations in protein structure (Liang et al, 2007;Mohammadi et al, 2009;Wallace and Janes, 2003). Structural changes in proteins caused by the binding of ligands are an essential part of the mechanism of action and regulation of biological activity.…”

“…Fluorescence spectroscopy is an efficient way to investigate intermolecular interactions (Collini et al, 2000;Kainz et al, 2009;Mohammadi et al, 2009;Wang et al, 2008). With most spectrofluorometers it is possible to record both excitation and emission spectra.…”

Spectroscopic investigation on the food components–drug interaction: The influence of flavonoids on the affinity of nifedipine to human serum albumin

“…For drug-HSA interaction, K 2 = 2/3, N = 1.336 and ΦD = 0.118 (Mohammadi et al, 2009). According to Eqs.…”

Studies on the interaction between promethazine and human serum albumin in the presence of flavonoids by spectroscopic and molecular modeling techniques

“…For drug-HSA interaction, K 2 = 2/3, N = 1.336 and ФD = 0.118 [59]. J is overlap integral between the emission spectrum of the donor and the absorption spectrum of the acceptor which can be calculated by the following equation:…”