Department of Chemistry, Faculty of Science, Eastern University Sri Lanka, Chenkalady, Sri Lanka.
Department of Chemistry, Faculty of Applied Sciences, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka.
J Mol Model. 2024 Nov 30;30(12):424. doi: 10.1007/s00894-024-06192-9.
Scopolin and scopoletin belong to the class of coumarins and have experimentally proven natural antioxidants. Natural antioxidants are crucial in mitigating the impact of oxidants in the human body through radical scavenging. Even though scopolin and scopoletin are proven antioxidants by experimental results, their antioxidant mechanisms still remained unexplained. In this study, Density functional theory (DFT) calculations were used to study the radical scavenging mechanisms of both scopolin and scopoletin using kinetic and thermodynamics parameters. The global parameters indicated that both scopolin and scopoletin have antioxidant properties. The band gap energy revealed that scopoletin (4.18 eV) has strong antioxidant activity compared to scopolin (4.31 eV). These studies found that hydrogen atom transfer (HAT) is the primary mechanism for CHOO• radical scavenging at the C-H bond in scopolin (91.98 kcal.mol) and the O-H bond in scopoletin (77.05 kcal.mol) due to their lowest bond dissociation energies. The calculated activation energy ( ) for the radical scavenging reaction, reconfirmed scopoletin ( =11.19 kcal.mol) performed as a better antioxidant compared to scopolin ( =20.91 kcal.mol). In this study, the results of DFT calculations confirmed that scopoletin exhibits a higher antioxidant capacity, and HAT mechanism is the most effective radical scavenging mechanism.
The antioxidant activity of scopolin and scopoletin was determined by DFT at the B3LYP/6-31G(d) level of theory. Global parameter calculations and frontier molecular orbital analysis were conducted to assess these compounds' capacity for scavenging radicals. Hydrogen atom transfer (HAT), sequential electron transfer proton transfer (SETPT), and sequential proton loss electron transfer (SPLET) mechanisms were the three main mechanisms that were taken into consideration. The potential energy surface (PES) verified the most appropriate processes shown by the enthalpy calculations.
莨菪亭和东莨菪亭属于香豆素类，已通过实验证明具有天然抗氧化剂的特性。天然抗氧化剂通过清除自由基，在减轻人体氧化剂的影响方面起着至关重要的作用。尽管莨菪亭和东莨菪亭通过实验结果被证明具有抗氧化剂的作用，但它们的抗氧化机制仍未得到解释。在这项研究中，使用密度泛函理论（DFT）计算来研究莨菪亭和东莨菪亭的自由基清除机制，使用动力学和热力学参数。全局参数表明莨菪亭和东莨菪亭都具有抗氧化特性。能带隙能量揭示了与莨菪亭（4.18eV）相比，东莨菪亭（4.31eV）具有更强的抗氧化活性。这些研究发现，氢原子转移（HAT）是在莨菪亭（91.98kcal·mol）的 C-H 键和东莨菪亭（77.05kcal·mol）的 O-H 键上清除 CHOO•自由基的主要机制，因为它们的键离解能最低。自由基清除反应的计算活化能（）进一步证实，与莨菪亭（=20.91kcal·mol）相比，东莨菪亭（=11.19kcal·mol）作为更好的抗氧化剂发挥作用。在这项研究中，DFT 计算结果证实，东莨菪亭表现出更高的抗氧化能力，并且 HAT 机制是最有效的自由基清除机制。
在 B3LYP/6-31G（d）理论水平下，通过 DFT 确定莨菪亭和东莨菪亭的抗氧化活性。进行全局参数计算和前沿分子轨道分析，以评估这些化合物清除自由基的能力。氢原子转移（HAT）、顺序电子转移质子转移（SETPT）和顺序质子丢失电子转移（SPLET）机制是考虑的三种主要机制。势能面（PES）验证了焓计算所示的最适当过程。
