UIC Center for Botanical Dietary Supplements Research, Pharmacognosy Institute, and Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, Illinois 60612, United States.
Center for Natural Product Technologies (CENAPT), Pharmacognosy Institute, and Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, Illinois 60612, United States.
J Nat Prod. 2023 Feb 24;86(2):256-263. doi: 10.1021/acs.jnatprod.2c00836. Epub 2023 Feb 6.
Monoterpenoids are integral to the chemical composition of the widely used adaptogenic dietary supplement . The present study expands the chemical space and stereochemical information about these taxon-specific constituents from the isolation and characterization of five geraniol-derived glucosides, -. While and exhibited almost identical NMR spectra and shared the same 2D structure ascribed to the 4-hydroxygeraniolglucoside previously described as rosiridin, the NMR-based Mosher ester method revealed the enantiomeric nature of their aglycone moieties. This marks the first report of enantiomeric aglycones among geraniol derivatives. These findings also resolve the long-standing dispute regarding the absolute configuration of rosiridin and congeneric C-4 hydroxylated geraniols and may help explain incongruent bioactivity reports of extract. Moreover, the three previously undescribed geranioloids - were fully characterized by extensive spectroscopic analysis. Quantum mechanics-driven H iterative functionalized spin analysis (QM-HifSA) was performed for all isolates and provides detailed NMR spin parameters, with adequate decimal place precision, which enable the distinction of such close congeners exhibiting near identical NMR spectra with high specificity. The outcomes also reinforce the importance of reporting chemical shifts and coupling constants with adequate decimal place precision as a means of achieving specificity and reproducibility in structural analysis.
单萜类化合物是广泛应用的适应性补充剂的化学组成的重要组成部分。本研究通过分离和鉴定五种牻牛儿醇衍生的葡萄糖苷（ ），扩展了这些分类特异性成分的化学空间和立体化学信息。尽管 和 的 NMR 光谱几乎完全相同，并且与先前描述的作为罗西丁的 4-羟基牻牛儿醇葡萄糖苷具有相同的 2D 结构，但基于 NMR 的 Mosher 酯法揭示了它们糖苷配基部分的对映异构体性质。这标志着首次报道牻牛儿醇衍生物中的对映异构体糖苷配基。这些发现还解决了关于罗西丁和同源 C-4 羟基化牻牛儿醇的绝对构型的长期争议，并可能有助于解释 提取物不一致的生物活性报告。此外，通过广泛的光谱分析对三种以前未描述的牻牛儿醇（ ）进行了全面表征。对所有分离物都进行了量子力学驱动的 H 迭代功能化自旋分析（QM-HifSA），提供了详细的 NMR 自旋参数，具有足够的十进制精度，可以区分具有高度特异性的近相同 NMR 光谱的此类紧密类似物。研究结果还强调了报告化学位移和耦合常数具有足够十进制精度的重要性，这是实现结构分析特异性和可重复性的一种手段。
