Structure of dihydrochalcones and related derivatives and their scavenging and antioxidant activity against oxygen and nitrogen radical species.

Quantum mechanical calculations at B3LYP/6-31G** level of theory were employed to obtain energy (E), ionization potential (IP), bond dissociation enthalpy (O-H BDE) and stabilization energies (DE(iso)) in order to infer the scavenging activity of dihydrochalcones (DHC) and structurally related compounds. Spin density calculations were also performed for the proposed antioxidant activity mechanism of 2,4,6-trihydroxyacetophenone (2,4,6-THA). The unpaired electron formed by the hydrogen abstraction from the phenolic hydroxyl group of 2,4,6-THA is localized on the phenolic oxygen at 2, 6, and 4 positions, the C₃ and C₆ carbon atoms at ortho positions, and the C₅ carbon atom at para position.