Flavone norartocarpetin and isoflavone 2′-hydroxygenistein: A spectroscopic study for structure, electronic property and antioxidant potential using DFT (Density functional theory)

Flavone and isoflavone derivatives have drawn much attention because of their antioxidant radical scavenging capacity. Based on computational methods, we now present the antioxidant potential results of flavone norartocarpetin (1) and isoflavone 2′-hydroxygenistein (2). The optimized structures of the neutral and radical forms have been carried out by DFT-B3LYP method with the 6-311++G (d,p) basis set. From the findings and thermodynamic point of view, ring B system of either flavone or isoflavone is considered as an active centre in facilitating antioxidant reactions. Antioxidant activities are mostly driven by the O–H bond dissociation enthalpy (BDE) following hydrogen atom transfer (HAT) mechanism. In all studied environments, the lowest BDE values are found in 4′-OH and 2′-OH of compounds 1-2, respectively. Isoflavone 2 possesses a higher antioxidant capacity than that of flavone 1. Of extensive analysis, intramolecular hydrogen bonds and solvents not only greatly influence on antioxidant aspect but also directly affect the structural properties, especially spectroscopic outcomes.