Tam Nguyen Minh, Thong Nguyen Minh, Le Huyen Trinh, Hoang Loc Phuoc, Mechler Adam, Vo Quan V
Computational Chemistry Research Group, Ton Duc Thang University, Ho Chi Minh City, Vietnam; Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
The University of Danang, Campus in Kon Tum, 704 Phan Dinh Phung, Kon Tum, Vietnam.
J Mol Graph Model. 2021 Jun;105:107892. doi: 10.1016/j.jmgm.2021.107892. Epub 2021 Mar 4.
Salvia species are frequently used in traditional medicine and are a source of diterpenoid antioxidants. In this study, the hydroperoxide radical scavenging activity of seven known abietane diterpenoids (ADs), isolated from Salvia barrelieri, are investigated using a quantum chemical approach. The ADs are 7-oxoroyleanone-12-methyl ether (1), 7a-acetoxyroyleanone-12-methyl ether (2), royleanone (3), horminone (4), 7-acetylhorminone (5), cryptojaponol (6), and inuroyleanol (7). It was found that formal hydrogen transfer is the main mechanism of the antiradical activity of these ADs in nonpolar environments, whereas the single electron transfer mechanism of anion states is favored in aqueous environment. The antioxidant activity of compounds 1-5 involves H-abstraction at the C7(15)-H bonds whereas for the compounds 6 and 7 the H abstraction takes place at the O12-H bond. The HOO scavenging activity of compounds 1-5 is minor in all of the studied media, however 6 and 7 exhibit excellent antiradical activity in aqueous solution. Remarkably, the HOO scavenging activity of compound 7 is substantially higher than that of Trolox, the reference antioxidant: the calculated rate constant was 122.3 times higher in polar and 6.1 times higher in nonpolar environments, respectively. Consistently 7 is a promising radical scavenger in physiological environments.
鼠尾草属植物常用于传统医学，是二萜类抗氧化剂的来源。在本研究中，采用量子化学方法研究了从巴雷利鼠尾草中分离出的七种已知松香烷二萜（ADs）的氢过氧化物自由基清除活性。这些ADs分别是7-氧代罗勒酮-12-甲醚（1）、7a-乙酰氧基罗勒酮-12-甲醚（2）、罗勒酮（3）、霍米酮（4）、7-乙酰基霍米酮（5）、隐日本醇（6）和异罗勒醇（7）。研究发现，在非极性环境中，形式氢转移是这些ADs抗自由基活性的主要机制，而在水环境中，阴离子态的单电子转移机制更受青睐。化合物1-5的抗氧化活性涉及C7(15)-H键处的氢原子提取，而化合物6和7的氢原子提取发生在O12-H键处。在所有研究的介质中，化合物1-5的HOO清除活性较小，然而化合物6和7在水溶液中表现出优异的抗自由基活性。值得注意的是，化合物7的HOO清除活性明显高于参考抗氧化剂Trolox：在极性环境中计算得到的速率常数分别高122.3倍，在非极性环境中高6.1倍。因此，化合物7在生理环境中是一种有前途的自由基清除剂。
