• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Phytochemical Analysis >On-line identification of unstable iridoids from Jamesbrittenia fodina by HPLC-MS and HPLC-NMR
【24h】

On-line identification of unstable iridoids from Jamesbrittenia fodina by HPLC-MS and HPLC-NMR

机译：HPLC-MS和HPLC-NMR在线鉴定山茱br中不稳定的类虹彩

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

HPLC-UV-MS analysis of the methanol extract of Jamesbrittenia fodina (Wild) O. M. Hilliard (Scrophulariaceae) revealed the presence of different iridoid cinnamic esters; however, isolation of these constituents was prevented by instability problems. HPLC-UV-MS and HPLC-NMR analysis of the mixtures obtained after a tentative isolation indicated that, in the first instance, instability was due to a light-induced cis/trans isomerisation of the cinnamic moieties. Further investigation of related compounds showed an additional instability problem linked to other chemical transformations. A detailed HPLC-NMR-MS study of these fractions demonstrated that the modifications occurred on the rhamnose moiety of these iridoids. It could be concluded that the second type of instability was attributable to transesterification of the cinnamic moiety on the rhamnose unit. The recording of stop-flow HPLC-NMR spectra for specific HPLC peaks permitted the direct monitoring of these transformations. Based on these on-line data, six new unstable aucubin derivatives were efficiently characterised.
机译：用HPLC-UV-MS分析山茱br（Wild）O。M. Hilliard（玄参科）的甲醇提取物，发现存在不同的虹彩肉桂酸酯。但是，不稳定问题阻止了这些成分的分离。初步分离后获得的混合物的HPLC-UV-MS和HPLC-NMR分析表明，不稳定性首先是由于肉桂酸部分的光诱导的顺式/反式异构化。对相关化合物的进一步研究表明，还有其他与化学转化有关的不稳定性问题。对这些馏分进行的详细HPLC-NMR-MS研究表明，修饰发生在这些环烯醚酮的鼠李糖部分上。可以得出结论，第二种类型的不稳定性归因于鼠李糖单元上肉桂酸部分的酯交换反应。记录特定HPLC峰的止流HPLC-NMR光谱可以直接监控这些转化。基于这些在线数据，有效地表征了六种新的不稳定的aucubin衍生物。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号