Amit Kumar, A K Bhagi
ABSTRACT
Curcumin is a yellow pigment of turmeric, a spice manufactured from the root of Curcuma longa and is currently the focus of enormous research owing to its antioxidant properties as the mechanism of action of curcumin for the antioxidant properties is not very clear. In the present study, the structures, energetic, one electron oxidation potential and global reactivity descriptors of curcumin in both neutral and charged states have been investigated using density-functional theory. The keto-enol tautomerism study shows that enol form is the predominant form of the compound. In order to probe the preferred site of reactivity, and hence antioxidant activity, the Fukui function; fk- has also been evaluated for curcumin in both keto and enol form of molecules. The trends observed in various global reactivity descriptors along with Fukui indices clearly indicates that curcumin is a potent antioxidant and the antioxidant activity of curcumin is mainly due to phenolic –OH groups in the two phenyl rings present in the molecule. The results obtained are important guidelines towards the detailed understanding of the antioxidant mechanism of curcumin.