Liang Y-S, Kim H K, Lefeber A W M, Erkelens C, Choi Y H, Verpoorte R
Division of Pharmacognosy, Section Metabolomics, Institute of Biology, Leiden University, 2300 RA Leiden, The Netherlands.
J Chromatogr A. 2006 Apr 21;1112(1-2):148-55. doi: 10.1016/j.chroma.2005.11.114.
Metabolic analysis showed a clear increase in phenylpropanoid levels in Brassica rapa leaves after treatment with methyl jasmonate. A fraction of phenylpropanoids was prepared by Diaion HP-20 and Sephadex LH-20 column chromatography after MeOH-water extraction. Even with these purification steps, isolation of each phenylpropanoid for structure elucidation is not easy due to the low levels in the plants (ca. 0.004%). A mixture was analyzed without further purification using HPLC-electrospray ionization mass spectrometry and NMR spectroscopy. Based on the NMR results including (1)H NMR, J-resolved, correlated spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlation (HMBC) spectra, both (1)H and (13)C resonances of the compounds were obtained. Using these NMR data, five phenylpropanoids conjugated with malate were identified: 5-hydroxyferuloyl-, caffeoyl-, coumaroyl-, feruloyl-, and sinapoyl malate. Of the compounds, 5-hydroxyferuloyl malate is a new phenylpropanoid. In addition to the five constitutive phenylpropanoids bearing trans-configuration, their cis forms, which are believed to be artifacts formed in the course of extraction steps, were also identified in the fraction.
代谢分析表明，用茉莉酸甲酯处理后的芜菁叶片中苯丙烷类化合物水平明显升高。甲醇 - 水提取后，通过Diaion HP - 20和Sephadex LH - 20柱色谱法制备了一部分苯丙烷类化合物。即便经过这些纯化步骤，由于植物中含量较低（约0.004%），分离每种用于结构解析的苯丙烷类化合物并不容易。使用高效液相色谱 - 电喷雾电离质谱法和核磁共振光谱法对未经进一步纯化的混合物进行了分析。基于包括¹H NMR、J - 分解、相关光谱（COSY）、异核单量子相干（HSQC）和异核多键相关（HMBC）光谱在内的核磁共振结果，获得了化合物的¹H和¹³C共振信号。利用这些核磁共振数据，鉴定出了五种与苹果酸共轭的苯丙烷类化合物：5 - 羟基阿魏酰苹果酸、咖啡酰苹果酸、香豆酰苹果酸、阿魏酰苹果酸和芥子酰苹果酸。其中，5 - 羟基阿魏酰苹果酸是一种新的苯丙烷类化合物。除了这五种具有反式构型的组成型苯丙烷类化合物外，在该组分中还鉴定出了它们的顺式形式，据信这些顺式形式是在提取过程中形成的假象。
