Antioxidant activity of Hibiscetin and Hibiscitrin: insight from DFT, NCI, and QTAIM

Computational Chemistry Strategies to Investigate the Antioxidant Activity of Flavonoids—An Overview

“…GCRPs are important, since they closely correlate with various physicochemical properties like bonding energies, aromaticity, and polarizability [113]. The advantage of The surface MEP map is an effective tool for predicting reaction sites and has already been applied to flavonoids [58]. There is a strong correlation between the MEP and the acidity of the molecule, indicating that the MEP can be used to estimate the pK a value of the hydroxyl groups at different positions on flavonoids [102].…”

“…NCI analysis is a potent tool to reveal these non-covalent interactions. • NCI analysis can intuitively and comprehensively depict the distribution of weak interactions of flavonoid molecules [27,58]. In NCI analysis, the interaction types are visualized using a color gradient, varying from blue to green indicating a gradual weakening of weak interactions, while red denotes increased resistance.…”

“…The surface MEP map is an effective tool for predicting reaction sites and has already been applied to flavonoids [ 58 ]. There is a strong correlation between the MEP and the acidity of the molecule, indicating that the MEP can be used to estimate the pK a value of the hydroxyl groups at different positions on flavonoids [ 102 ].…”

“…The minimum value is considered the final HAE for each site of flavonoids [ 170 ]. Conversely, to obtain the BDE of flavonoids, the lowest energy conformation is first identified, followed by separate calculations of the bond dissociation enthalpy for each site [ 58 ].…”

A density functional theory benchmark on antioxidant-related properties of polyphenols

“…From a fundamental perspective, it is well established that various mechanisms associated with the antioxidant potential of polyphenols (such as hydrogen atom transfer (HAT), single electron transfer (SET), and other less common paths) can be explored through the use of electronic structure computations 6,7 and, thus, numerous computationally-based investigations on probing antioxidant-related mechanisms can be found in the recent literature. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Perhaps the main mechanism regarding antioxidant activity in polyphenols, the HAT mechanism, [23][24][25][26][27] can be written as ArOH + R -ArO + RH, (1) where an O-H bond is homolyticaly cleaved and an H atom is transferred from the polyphenol (ArOH) to the free radical (R ) to offset it (RH). Hence, bond dissociation enthalpies (BDEs) can be used to estimate the energy necessary for the O-H bonds to be broken.…”