School of Chemistry, National University of Ireland Galway, University Road, H91 TK33 Galway, Ireland.
Pharmacology and Therapeutics, School of Medicine, National University of Ireland Galway, University Road, H91 W2TY Galway, Ireland.
Mar Drugs. 2021 Jan 19;19(1):42. doi: 10.3390/md19010042.
Brown alga is an extraordinarily rich source of linear (acylic) diterpenes with enormous structural diversity. As part of our interest into secondary metabolites of the Irish seaweeds, here we report four new acyclic diterpenes (-) and seven known terpenoids (-) from the CHCl extract of . The planar structures of the new metabolites were elucidated by means of 1D and 2D NMR, HRMS, and FT-IR spectroscopy. Since linear diterpenes are highly flexible compounds, the assignment of their stereochemistry by conventional methods, e.g., NOESY NMR, is difficult. Therefore, we employed extensive quantum-mechanical prediction of NMR chemical shifts and optical rotation analyses to identify the relative and absolute configurations of the new compounds -. Several compounds moderately inhibited the human breast cancer cell line (MDA-MB-231) with IC values ranging from 10.0 to 33.5 μg/mL. This study not only demonstrates the vast capacity of the Irish to produce highly oxygenated linear diterpenoids, but also highlights the potential of new methodologies for assignment of their stereogenic centers.
棕藻是一类具有丰富结构多样性的线性（非环）二萜类化合物的重要来源。作为我们对爱尔兰海藻次生代谢产物研究的一部分，我们从. 的 CHCl 提取物中分离得到了四个新的非环二萜类化合物（-）和七个已知的萜类化合物（-）。新代谢产物的平面结构通过 1D 和 2D NMR、高分辨质谱、FT-IR 光谱等手段得到阐明。由于线性二萜类化合物具有高度的灵活性，因此通过传统方法（例如，NOESY NMR）来确定其立体化学构型较为困难。因此，我们采用了广泛的量子力学预测 NMR 化学位移和旋光分析来确定新化合物的相对和绝对构型。几种化合物对人乳腺癌细胞系（MDA-MB-231）具有中等抑制活性，IC 值范围为 10.0 至 33.5 μg/mL。本研究不仅展示了爱尔兰. 产生高度氧化的线性二萜类化合物的巨大潜力，还突出了新方法在确定其手性中心方面的应用潜力。
