University of Hohenheim, Institute of Food Chemistry (170b), Garbenstraße 28, D-70599, Stuttgart, Germany.
Phycomarin, Bredenbergsweg 5, D-21149, Hamburg, Germany.
Chemosphere. 2021 Dec;284:131310. doi: 10.1016/j.chemosphere.2021.131310. Epub 2021 Jun 23.
Environmentally relevant halogenated natural products (HNPs) are frequently similarly high concentrated in marine biota as major anthropogenic persistent organic pollutants (POPs). The lack of widely available reference standards, however, hampers the in-depth research of several HNPs. For instance, (1R,2S,4R,5R,1'E)-2-bromo-1-bromomethyl-1,4-dichloro-5-(2'-chloroethenyl)-5-methylcyclohexane (MHC-1), which is produced by species referred to the red seaweed Plocamium cartilagineum has not yet been synthesized due to its complex structure and stereochemistry. For this reason, we aimed to establish a method for fast isolation of mg-amounts of MHC-1 from its natural producer based on countercurrent chromatography (CCC). Five biphasic solvent systems were tested and finally, the solvent system acetonitrile/n-hexane/toluene (9:9:2, v/v/v) was selected for the separations due to its suitable partition coefficient of MHC-1 (K = 0.52). n-Hexane extracts of dried P. cartilagineum were directly injected into the CCC system. Four subsequent CCC runs from three samples of Plocamium cartilagineum (two from Heligoland, Germany and one from Brittany, France) could be performed with high reproducibility. Together, the main fraction provided ~16 mg MHC-1 in a purity of >97% according to GC/FID, GC/ECNI-MS and NMR analysis. This amount could be used to prepare ~1600 quantitative standard solutions of MHC-1. The high MHC-1 content in the seaweed sample collected at Brittany indicated that this area was another hotspot of MHC-1.
环境相关卤代天然产物（HNPs）在海洋生物群中与主要人为持久性有机污染物（POPs）的浓度相似。然而，由于缺乏广泛可用的参考标准，几种 HNPs 的深入研究受到阻碍。例如，（1R，2S，4R，5R，1'E）-2-溴-1-溴甲基-1,4-二氯-5-（2'-氯乙烯基）-5-甲基环己烷（MHC-1）由红海藻 Plocamium cartilagineum 产生，由于其复杂的结构和立体化学，尚未被合成。出于这个原因，我们旨在建立一种基于逆流色谱（CCC）从其天然产生者中快速分离毫克级 MHC-1 的方法。测试了五种双相溶剂系统，最终由于 MHC-1 的适宜分配系数（K=0.52），选择了乙腈/正己烷/甲苯（9:9:2，v/v/v）溶剂系统用于分离。干燥的 P. cartilagineum 的正己烷提取物直接注入 CCC 系统。从 Heligoland，德国和 Brittany，法国的两个 Plocamium cartilagineum 样本中进行了四次后续的 CCC 运行，具有高度的重现性。总共，主要馏分根据 GC/FID、GC/ECNI-MS 和 NMR 分析提供了16mg 纯度>97%的 MHC-1。这个量可以用来制备1600 个 MHC-1 的定量标准溶液。在 Brittany 收集的海藻样本中 MHC-1 的高含量表明该地区是 MHC-1 的另一个热点。
