Abstract
Quantum-chemical calculations based on the density functional theory (DFT) at the B3LYP/6–311 + + G(2d,2p)//B3LYP/6–31G(d,p) level were employed to study the relationship between the antioxidant properties and chemical structures of six dendrocandin (DDCD) analogues in the gas phase and two solvents (methanol and water). The hydrogen atom transfer (HAT), electron-transfer-proton-transfer (ET-PT), and sequential proton-loss-electron-transfer (SPLET) mechanisms are explored. The highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), reactivity indices (η, μ, ω, ω+, and ω–), and molecular electrostatic potentials (MEPs) were also evaluated. The results suggest that the D ring plays an important role in mediating the antioxidant activity of DDCDs. For all the studied compounds, indicating that HAT was identified as the most favorable mechanism, whereas the SPLET mechanism was the most thermodynamically favorable pathway in polar solvents. The results of our study should aid in the development of new or modified antioxidant compounds.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11224-022-01895-2.
Highlights
Oxidative stress generated by an increase in free radical levels is a pro-oxidative state in which the reactive oxygen species (ROS) level exceeds the capability of antioxidant defense mechanisms
The results clearly indicated that the electronic density in DDCD1 is concentrated in the oxygen of the O(1)-OH in the A-ring, which is directly attached to the benzene ring
The B3LYP/6–311 + + G(2d,2p)// B3LYP/6–31(d,p) level of the density functional theory (DFT) was applied to study the radical scavenging activity of six DDCD analogues. Thermodynamic parameters such as bond dissociation enthalpy (BDE), ionization potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA), and electron transfer enthalpy (ETE) were computed for DDCDs 1–6 in the gas phase and in solvents to evaluate the possible mechanism
Summary
Oxidative stress generated by an increase in free radical levels is a pro-oxidative state in which the reactive oxygen species (ROS) level exceeds the capability of antioxidant defense mechanisms. The HOMO and LUMO energy distributions, MEPs, and the spin density for each radical atom were determined using the B3LYP/6–311 + + G(2d,2p) level of the theory for all optimized structures of the investigated compounds.
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