title: Biophysical studies on curcumin-deoxyribonucleic acid interaction: spectroscopic and calorimetric approach.
abstract: The interaction of the dietary pigment curcumin with herring testes deoxyribonucleic acid was studied by biophysical and microcalorimetric techniques. Curcumin bound to DNA exhibiting hypochromic effect in absorbance and enhanced intensity of its fluorescence. The binding a affinity value evaluated from spectroscopy data was of the order 10(4) M(-1). The quantum efficiency value testified the occurrence of energy transfer from the DNA base pairs to the curcumin molecules. Displacement studies of DNA bound DAPI, Hoechst and ethidium bromide suggested binding of curcumin to be in the minor groove of the DNA. Moderate conformational perturbations of the B-form structure of DNA occurred on binding. The binding affinity weakened as the DNA GC content enhanced. The binding was characterized by negative enthalpy and positive entropy changes; the binding affinity from calorimetry was in good agreement with that evaluated from the spectral data. The binding was dominated by hydrophobic and other non-polyelectrolytic forces; the polyelectrolytic forces contributing only a quarter to the total Gibbs energy at 50 mM [Na(+)].
authors.affiliation: Biophysical Chemistry Laboratory, Chemistry Division, CSIR - Indian Institute of Chemical Biology, Kolkata 700 032, India.
authors.forename: Anirban
authors.initials: A
authors.lastname: Basu
authors.forename: Gopinatha Suresh
authors.initials: GS
authors.lastname: Kumar
mesh_terms: D065966:Absorption, Physicochemical; D002151:Calorimetry; D003474:Curcumin / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004583:Electrons; D057446:Hydrodynamics; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D013057:Spectrum Analysis; D013816:Thermodynamics
chemical_list: D004247:DNA; D003474:Curcumin
keywords: Curcumin; Energetics; Minor groove binder