The University of Danang-University of Technology and Education, Danang 550000, Vietnam.
Department of Chemistry, The University of Danang-University of Science and Education, Danang 550000, Vietnam.
J Org Chem. 2020 Dec 4;85(23):15514-15520. doi: 10.1021/acs.joc.0c02258. Epub 2020 Nov 5.
Syringic acid (SA) is a natural phenolic acid found in vegetables, fruits, and other plant-based foods. A range of biological activities were proposed for this compound including anticancer, antimicrobial, anti-inflammation, and anti-diabetic activities, as well as antioxidant and antinitrosant properties. In this study, the focus is on the latter two. The HO, HOO, NO, and NO scavenging activities of SA were evaluated in physiological environments by kinetic and thermodynamic calculations. The computed rate constants of the HO radical scavenging of SA were 4.63 × 10 and 9.77 × 10 M s in polar and nonpolar solvents, respectively. A comparison with the experimentally determined rate constant in aqueous solution yields a / ratio of 0.3, thus the computed kinetic data are reasonably accurate. SA exhibited excellent HOO and NO scavenging activity in water ((HOO) = 1.53 × 10 M s and (NO) = 1.98 × 10 M s), whereas it did not show NO scavenging activity in any of the studied environments. In lipid medium, SA exhibited weak activity. Thus, in polar environments, the HOO radical scavenging of SA is 1.53 times higher than that of ascorbic acid. Consistently, SA is a promising antioxidant and antinitrosant agent in polar environments.
丁香酸（SA）是一种天然酚酸，存在于蔬菜、水果和其他植物性食物中。该化合物具有一系列生物活性，包括抗癌、抗菌、抗炎和抗糖尿病活性，以及抗氧化和抗亚硝化活性。在这项研究中，重点关注后两种活性。通过动力学和热力学计算，评估了 SA 在生理环境中对 HO、HOO、NO 和 NO 的清除活性。SA 清除 HO 自由基的计算速率常数在极性和非极性溶剂中分别为 4.63×10 和 9.77×10 M s。与水溶液中实验确定的速率常数进行比较，得到 / 的比值为 0.3，因此计算出的动力学数据相当准确。SA 在水中表现出优异的 HOO 和 NO 清除活性（（HOO）= 1.53×10 M s 和（NO）= 1.98×10 M s），而在任何研究环境中均未表现出对 NO 的清除活性。在脂质介质中，SA 表现出较弱的活性。因此，在极性环境中，SA 清除 HOO 自由基的活性比抗坏血酸高 1.53 倍。一致地，SA 在极性环境中是一种有前途的抗氧化剂和抗亚硝化剂。
