DOI: https://doi.org/10.36347/sjavs.2025.v12i11.005

Pages: 323-329

In this paper, the polyhydroxy antioxidant molecule R was designed based on thymol and perillaldehyde. The geometric configuration of the antioxidant R molecule was optimized at the BHandHLYP/6-31+G(d) level using density functional theory, and frequency analysis was conducted. The calculation results show that in the process of the antioxidant molecule R reacting with hydroxyl radicals, Path V has the lowest activation energy (ΔG≠TS5 = 135.46 kJ∙mol-1), which is more advantageous from the perspective of molecular dynamics. The Relative Gibbs Free Energy of Path V is less than 0 kJ∙mol-1, and from the perspective of chemical thermodynamics, it can proceed spontaneously in the forward direction. This can demonstrate that Path V is the advantageous path for antioxidants to eliminate hydroxyl radicals. In this calculation, the influencing factors of temperature on the reaction mechanism were investigated. Within the range of 243K ~ 303K, the enthalpies change range of multiple reaction pathways between R molecules and hydroxyl radicals was 98.68 ~ 157.49 kJ∙mol-1. Moreover, with the increase of temperature, there was no significant change in the horizontal images of each pathway. The activated Gibbs Free Energy in the transition state increases slowly with the rise in temperature, and the increase in each path is basically the same, while the reaction mechanism remains unchanged. Therefore, temperature has no significant effect on the reaction mechanism of antioxidant R in eliminating hydroxyl radicals.