Gau Jana, Prévost Martine, Van Antwerpen Pierre, Sarosi Menyhárt-Botond, Rodewald Steffen, Arnhold Jürgen, Flemmig Jörg
Institute for Medical Physics and Biophysics, Medical Faculty, University of Leipzig , Härtelstraße 16-18, 04107 Leipzig, Germany.
J Nat Prod. 2017 May 26;80(5):1328-1338. doi: 10.1021/acs.jnatprod.6b00915. Epub 2017 Apr 3.
Several hydrolyzable tannins, proanthocyanidins, tannin derivatives, and a tannin-rich plant extract of tormentil rhizome were tested for their potential to regenerate the (pseudo-)halogenating activity, i.e., the oxidation of SCN to hypothiocyanite OSCN, of lactoperoxidase (LPO) after hydrogen peroxide-mediated enzyme inactivation. Measurements were performed using 5-thio-2-nitrobenzoic acid in the presence of tannins and related substances in order to determine kinetic parameters and to trace the LPO-mediated OSCN formation. The results were combined with docking studies and molecular orbital analysis. The OSCN-regenerating effect of tannin derivatives relates well with their binding properties toward LPO as well as their occupied molecular orbitals. Especially simple compounds like ellagic acid or methyl gallate and the complex plant extract were found as potent enzyme-regenerating compounds. As the (pseudo-)halogenating activity of LPO contributes to the maintenance of oral bacterial homeostasis, the results provide new insights into the antibacterial mode of action of tannins and related compounds. Furthermore, chemical properties of the tested compounds that are important for efficient enzyme-substrate interaction and regeneration of the OSCN formation by LPO were identified.
对几种可水解单宁、原花青素、单宁衍生物以及富含单宁的委陵菜根茎植物提取物进行了测试，以考察它们在过氧化氢介导的乳过氧化物酶（LPO）失活后，恢复其（拟）卤化活性（即将硫氰酸盐氧化为次硫氰酸盐OSCN）的潜力。在单宁及相关物质存在的情况下，使用5-硫代-2-硝基苯甲酸进行测量，以确定动力学参数并追踪LPO介导的OSCN形成。研究结果与对接研究和分子轨道分析相结合。单宁衍生物的OSCN再生效应与其对LPO的结合特性以及所占据的分子轨道密切相关。尤其是发现诸如鞣花酸或没食子酸甲酯等简单化合物以及复杂的植物提取物是有效的酶再生化合物。由于LPO的（拟）卤化活性有助于维持口腔细菌的稳态，这些结果为单宁及相关化合物的抗菌作用模式提供了新的见解。此外，还确定了测试化合物对于LPO高效酶-底物相互作用以及OSCN形成再生而言重要的化学性质。
