Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina C.P. 09340 Iztapalapa, México D.F., Mexico.
J Phys Chem B. 2009 Dec 10;113(49):16077-81. doi: 10.1021/jp907906h.
The OOH radical reactions with allicin and its Cope elimination products (2-propenesulfenic acid and thioacrolein) in aqueous solution have been studied. The CBS-QB3 quantum chemistry method has been used, with geometries and frequencies at BHandHLYP/6-311++G(d,p) level and conventional transition state theory. 2-Propenesulfenic acid is predicted to be over 1000 times more reactive toward OOH radical than allicin (2.60 x 10(7) vs 7.38 x 10(3) L mol(-1) s(-1), at 298 K). Accordingly, our results strongly support the novel suggestion by Vaidya et al. (Angew. Chem., Int. Ed. 2009, 48, 157) that the active ingredient responsible for the free radical scavenging activity of garlic is actually 2-propenesulfenic acid and not allicin. In addition, direct reaction branching ratios and product distribution for the three studied reactions are proposed for the first time.
OOH 自由基与大蒜素及其 Cope 消除产物（2-丙烯亚磺酸和硫代丙烯醛）在水溶液中的反应已经得到研究。使用 CBS-QB3 量子化学方法，在 BHandHLYP/6-311++G(d,p)水平上进行几何和频率计算，并采用传统过渡态理论。预测 2-丙烯亚磺酸对 OOH 自由基的反应活性比大蒜素高 1000 多倍（在 298 K 时，2.60 x 10(7) 与 7.38 x 10(3) L mol(-1) s(-1)）。因此，我们的结果强烈支持 Vaidya 等人的新建议（Angew. Chem.，Int. Ed. 2009，48，157），即负责大蒜清除自由基活性的活性成分实际上是 2-丙烯亚磺酸，而不是大蒜素。此外，首次提出了三种研究反应的直接反应分支比和产物分布。
