Spectroscopic exploring the affinities, characteristics, and mode of binding interaction of curcumin with DNA

Curcumin is a polyphenolic bioactive compound found in the spice turmeric endowed with diverse pharmacological and biological activities. In this study, fluorescence spectroscopy in combination with UV-Vis absorbance spectroscopy was employed to investigate the high affinity binding of curcumin to herring sperm DNA (hs-DNA). From the series of studies undertaken in the present program, for example, steady-state emission; absorption; the effect of denaturants; competition experiment; and anion (iodide) ion-induced fluorescence quenching; the mode of binding of curcumin into the DNA helix has been substantiated to be principally intercalative. Binding parameters calculating from Stern-Volmer method and Scatchard method showed that curcumin bind to hs-DNA with the binding affinities of the order 10(4 )L mol(-1). The effects of ionic strength, chemical denaturants, thermal denaturation and pH were studied to show the factors of the interaction, and provided further support for the intercalative binding mode. In addition, the methods and techniques used in the present work can also be exploited to study the interaction of curcumin with other biological, biomimicking assemblies and drug delivery vehicles, and so forth.