Estudo químico e avaliação de atividades biológicas da espécie Vatairea guianensis AUBL. (FABACEAE)

Role of the Solvent and Intramolecular Hydrogen Bonds in the Antioxidative Mechanism of Prenylisoflavone from Leaves of Vatairea guianensis

“…Preliminary discussion has indicated that among the seven compounds extracted from the plant V. guianensis, only species S10 and S11 exhibited significant free radical scavenging activity. 32 The results indicate that isoflavone S10 would be a more accessible compound for hydrogen absorption processes. However, nothing is known about the hydrogen elimination pathway, which is problematic as the environment can easily change this mechanism from gas to solvent.…”

“…However, previous research indicates that the OH group is The Journal of Physical Chemistry A energetically favorable for hydrogen removal. 32 Therefore, the molecular sites of interest are denoted as a, b, and c. To characterize the mechanism of HAT, Table 2 presents the results for BDE and ΔBDE = BDE molecule − BDE phenol , which is defined using the phenol molecule as a reference. This last index is crucial to establish an efficient criterion for antioxidant behavior.…”

“…From Table 2, it can be seen that the hierarchy is S11a < S11b < S11c, indicating that the position S11c is the path for hydrogen removal, requiring −5 kJ/mol less energy relative to phenol. However, de Souza et al 32 have suggested that between the two compounds, S10 exhibits better antioxidant behavior than S11. Quantum mechanical calculations in the gas phase support this trend, with S10c < S11c for the HAT mechanism at the ωB97XD/6-311++G(d,p) level of theory.…”