Free Radical Scavenger Properties of α-Mangostin: Thermodynamics and Kinetics of HAT and RAF Mechanisms
Free Radical Scavenger Properties of α-Mangostin: Thermodynamics and Kinetics of HAT and RAF Mechanisms
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DOI：
10.1021/jp205496u
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发表时间：
2011-11-03
影响因子：
3.3
通讯作者：
Vargas, Rubicelia
中科院分区：
文献类型：
--
作者：
Martinez, Ana;Galano, Annia;Vargas, Rubicelia
山竹是一种热带水果，对人类健康有益，因为它富含花色苷和氧杂蒽酮，这些物质被认为是生物活性化合物，被描述为良好的自由基清除剂。它最活跃的化合物之一是α-芒果苷。本文采用密度泛函理论方法对α-倒捻子素及其单阴离子的自由基清除能力进行了理论研究。两个众所周知的反应机理进行了研究：氢原子转移（HAT）和自由基加合物的形成（RAF）。还考虑了另外两种机制：顺序电子质子转移（SEPT）和质子耦合电子转移（PCET）。根据热力学和动力学，α-倒捻子素及其去质子化形式通过HAT机制是良好的自由基清除剂，其中阴离子（去质子化）形式比中性形式更具反应性。它们清除OOH自由基的能力与胡萝卜素相似，高于大蒜素，远高于褪黑激素和N-乙酰半胱氨酸酰胺，比2-丙烯磺酸低约15倍。
Mangosteen is a tropical fruit that presents beneficial effects on human health since it is rich in anthocyanins and xanthones, which are considered bioactive compounds that have been described as good free radical scavengers. One of its most active compounds is alpha-mangostin. In this report, a theoretical study on the free radical scavenger capacity of alpha-mangostin and its monoanion is analyzed using the density functional theory approximation. Two well-known reaction mechanisms are investigated: the hydrogen atom transfer (HAT) and the radical adduct formation (RAF). Two other mechanisms are also considered: sequential electron proton Transfer (SEPT) and proton coupled electron transfer (PCET). According to thermodynamics and kinetics, alpha-mangostin and its deprotonated form are good free radical scavenger through the HAT mechanism, with the anionic (deprotonated) form being more reactive than the neutral one. Their capacity to scavenge OOH free radical is similar to that of carotenes, higher than that of allicin, much higher than that of melatonin and N-acetylcysteine amide, and about 15 times lower than that of 2-propenesulfenic acid.