A DFT study on the radical scavenging activity of juglone and its derivatives

The structural and electronic properties of juglone and its derivatives and their radicals were investigated at density functional level. The topology of electron density and the hydrogen bond properties of the studied structures were investigated using the Atoms in Molecules (AIM) theory. It turned out that the presence of the dihydroxy functionality increases the radical stability through hydrogen bond formation and favors hydrogen atom abstraction. The introduction of electron-donating groups for the molecules increases the activities of antioxidants. Moreover, juglone and its derivatives appear to be good candidates for the one-electron-transfer mechanism. Their planar conformation and the extended electronic delocalization between adjacent rings determine low ionization potential (IP) values, and it can be further improved by the introduction of the electron-donating groups for the molecules.