• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of mass spectrometry: JMS >Evidence of noncovalent complexes in some natural extracts: Ceylon tea and mate extracts
【24h】

Evidence of noncovalent complexes in some natural extracts: Ceylon tea and mate extracts

机译：一些自然提取物中非共价复合物的证据：锡兰茶和伴侣提取物

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

Considering the high complexity of natural extracts, because of the presence of organic molecules of different chemical nature, the possibility of formation of noncovalent complexes should be taken into account. In a previous investigation, the formation of bimolecular complexes between caffeine and catechins in green tea extracts (GTE) has been experimentally proven by means of mass spectrometric and H-1 nuclear magnetic resonance experiments. The same approaches have been employed in the present study to evaluate the presence of bimolecular complexes in Ceylon tea and mate extracts. The obtained results show that in the case of Ceylon tea extracts, protonated theaflavin is detectable, together with theaflavin/caffein complexes, while caffeine/catechin complexes, already detected in green tea, are still present but at lower concentration. This aspect is evidenced by the comparison of precursor ion scans performed on protonated caffeine for the two extracts. The spectra obtained in these conditions for GTE and Ceylon tea show that the complexes of caffeine with epigallocatechin (EGC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG), highy abundant in the case of GTE (signal-to-chemical noise ratio in the range 50-100), are negligible (signal-to-chemical noise ratio in the range 2-3) in the case of Ceylon tea. Mate extracts show the formation of bimolecular complexes involving caffeine but not catechins, and chlorogenic acid becomes responsible for other complex formation. Under positive ion and negative ion conditions, accurate mass measurements allow the identification of malealdehyde, chlorogenic acid, caffeine, two isomers of dicaffeoylquinic acid, rutin, and kaempferol-3-O-rutinoside. These data indicate that the formation of complexes in natural extracts is a common behavior, and their presence must be considered in the description of natural extracts and, consequently, in their biological activity.
机译：考虑到自然提取物的高复杂性，由于存在不同化学性质的有机分子，应考虑形成非共价复合物的可能性。在先前的研究中，通过质谱和H-1核磁共振实验，通过质谱和H-1核磁共振实验在实验证明了绿色茶提取物（GTE）之间的咖啡因和儿茶素之间的分散复合物的形成。本研究已经采用了相同的方法，以评估锡兰茶和伴侣提取物中的双分子复合物的存在。所得的结果表明，在锡兰茶提取物的情况下，质子化的Theaflawin可检测到尾蛋白/含咖啡络合物，而在绿茶中已经检测到的咖啡因/儿茶素复合物仍然存在，但仍处于较低浓度。通过对两种提取物对质子化咖啡因进行的前体离子扫描的比较来证明该方面。在这些GTE和锡兰茶的这些条件下获得的光谱表明，咖啡因的复合物与EPIGALLOCATECHIN（EGC），EPICATECHINGALLET（ECG），和EPIGALLOCATECHIN GALLATE（EGCG），在GTE的情况下高（信号与化学噪声）在锡兰茶的情况下，在50-100范围内的比率可以忽略不计（2-3的信号 - 化学噪声比）。伴侣提取物显示涉及咖啡因但不是儿茶素的双分子复合物的形成，并且绿原酸因其他复杂的形成负责。在正离子和负离子条件下，精确的质量测量允许鉴定麦莱醛，绿原酸，咖啡因，二聚带酰基喹啉的两种异构体，Rutin和Kaempferol-3-O-Rutinoside。这些数据表明，自然提取物中的复合物的形成是一种常见的行为，并且它们的存在必须在自然提取物的描述中考虑，并且因此在其生物学活性中。

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